DispatcherServlet

DispatcherServlet源码分析：

public class DispatcherServlet extends FrameworkServlet {


<span style="white-space:pre">	</span>/**
         * 定义了spring mvc各种处理器在bean factory中的key
         * ps:handlerMapping、handlerAdapter、handlerExceptionResolver、viewResolver比较特殊，默认是用不到的，只有把相关的设置设置为false才起作用
         */
<span style="white-space:pre">	</span>public static final String MULTIPART_RESOLVER_BEAN_NAME = "multipartResolver";
<span style="white-space:pre">	</span>public static final String LOCALE_RESOLVER_BEAN_NAME = "localeResolver";
<span style="white-space:pre">	</span>public static final String THEME_RESOLVER_BEAN_NAME = "themeResolver";
<span style="white-space:pre">	</span>public static final String HANDLER_MAPPING_BEAN_NAME = "handlerMapping";
<span style="white-space:pre">	</span>public static final String HANDLER_ADAPTER_BEAN_NAME = "handlerAdapter";
<span style="white-space:pre">	</span>public static final String HANDLER_EXCEPTION_RESOLVER_BEAN_NAME = "handlerExceptionResolver";
<span style="white-space:pre">	</span>public static final String REQUEST_TO_VIEW_NAME_TRANSLATOR_BEAN_NAME = "viewNameTranslator";
<span style="white-space:pre">	</span>public static final String VIEW_RESOLVER_BEAN_NAME = "viewResolver";
<span style="white-space:pre">	</span>public static final String FLASH_MAP_MANAGER_BEAN_NAME = "flashMapManager";


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * 获取ApplicationContext的key
<span style="white-space:pre">	</span> * 获取方法RequestContextUtils#getWebApplicationContext
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>public static final String WEB_APPLICATION_CONTEXT_ATTRIBUTE = DispatcherServlet.class.getName() + ".CONTEXT";


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * 获取当前spring mvc各种处理器的key
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>public static final String LOCALE_RESOLVER_ATTRIBUTE = DispatcherServlet.class.getName() + ".LOCALE_RESOLVER";
<span style="white-space:pre">	</span>public static final String THEME_RESOLVER_ATTRIBUTE = DispatcherServlet.class.getName() + ".THEME_RESOLVER";
<span style="white-space:pre">	</span>public static final String THEME_SOURCE_ATTRIBUTE = DispatcherServlet.class.getName() + ".THEME_SOURCE";
<span style="white-space:pre">	</span>public static final String INPUT_FLASH_MAP_ATTRIBUTE = DispatcherServlet.class.getName() + ".INPUT_FLASH_MAP";
<span style="white-space:pre">	</span>public static final String OUTPUT_FLASH_MAP_ATTRIBUTE = DispatcherServlet.class.getName() + ".OUTPUT_FLASH_MAP";
<span style="white-space:pre">	</span>public static final String FLASH_MAP_MANAGER_ATTRIBUTE = DispatcherServlet.class.getName() + ".FLASH_MAP_MANAGER";


<span style="white-space:pre">	</span>/** 当映射找不到时的日志. */
<span style="white-space:pre">	</span>public static final String PAGE_NOT_FOUND_LOG_CATEGORY = "org.springframework.web.servlet.PageNotFound";


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * spring mvc各种处理器的默认配置
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>private static final String DEFAULT_STRATEGIES_PATH = "DispatcherServlet.properties";




<span style="white-space:pre">	</span>/** 定义找不到映射的log. */
<span style="white-space:pre">	</span>protected static final Log pageNotFoundLogger = LogFactory.getLog(PAGE_NOT_FOUND_LOG_CATEGORY);


<span style="white-space:pre">	</span>private static final UrlPathHelper urlPathHelper = new UrlPathHelper();


<span style="white-space:pre">	</span>private static final Properties defaultStrategies;


<span style="white-space:pre">	</span>static {
<span style="white-space:pre">		</span>// 读取配置文件信息(包含了spring mvc各种默认的处理器)
<span style="white-space:pre">		</span>try {
<span style="white-space:pre">			</span>ClassPathResource resource = new ClassPathResource(DEFAULT_STRATEGIES_PATH, DispatcherServlet.class);
<span style="white-space:pre">			</span>defaultStrategies = PropertiesLoaderUtils.loadProperties(resource);
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>catch (IOException ex) {
<span style="white-space:pre">			</span>throw new IllegalStateException("Could not load 'DispatcherServlet.properties': " + ex.getMessage());
<span style="white-space:pre">		</span>}
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/** 当为true时，加载所有集成了HandlerMapping的bean，当为false时，只加载名为“handlerMapping”的bean */
<span style="white-space:pre">	</span>private boolean detectAllHandlerMappings = true;


<span style="white-space:pre">	</span>/** 同理detectAllHandlerMappings(handlerAdapter) */
<span style="white-space:pre">	</span>private boolean detectAllHandlerAdapters = true;


<span style="white-space:pre">	</span>/** 同理detectAllHandlerMappings(handlerExceptionResolver) */
<span style="white-space:pre">	</span>private boolean detectAllHandlerExceptionResolvers = true;


<span style="white-space:pre">	</span>/** 同理detectAllHandlerMappings(viewResolver) */
<span style="white-space:pre">	</span>private boolean detectAllViewResolvers = true;


<span style="white-space:pre">	</span>/** 请求处理后是否清空 */
<span style="white-space:pre">	</span>private boolean cleanupAfterInclude = true;


<span style="white-space:pre">	</span>/** 定义spring mvc各种处理器对象 */
<span style="white-space:pre">	</span>private MultipartResolver multipartResolver;
<span style="white-space:pre">	</span>private LocaleResolver localeResolver;
<span style="white-space:pre">	</span>private ThemeResolver themeResolver;
<span style="white-space:pre">	</span>private List<HandlerMapping> handlerMappings;
<span style="white-space:pre">	</span>private List<HandlerAdapter> handlerAdapters;
<span style="white-space:pre">	</span>private List<HandlerExceptionResolver> handlerExceptionResolvers;
<span style="white-space:pre">	</span>private RequestToViewNameTranslator viewNameTranslator;
<span style="white-space:pre">	</span>private FlashMapManager flashMapManager;
<span style="white-space:pre">	</span>private List<ViewResolver> viewResolvers;




<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * 默认WebApplicationContext为XmlWebApplicationContext
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>public DispatcherServlet() {
<span style="white-space:pre">		</span>super();
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
         * 设置WebApplicationContext
         */
<span style="white-space:pre">	</span>public DispatcherServlet(WebApplicationContext webApplicationContext) {
<span style="white-space:pre">		</span>super(webApplicationContext);
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>public void setDetectAllHandlerMappings(boolean detectAllHandlerMappings) {
<span style="white-space:pre">		</span>this.detectAllHandlerMappings = detectAllHandlerMappings;
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>public void setDetectAllHandlerAdapters(boolean detectAllHandlerAdapters) {
<span style="white-space:pre">		</span>this.detectAllHandlerAdapters = detectAllHandlerAdapters;
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>public void setDetectAllHandlerExceptionResolvers(boolean detectAllHandlerExceptionResolvers) {
<span style="white-space:pre">		</span>this.detectAllHandlerExceptionResolvers = detectAllHandlerExceptionResolvers;
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>public void setDetectAllViewResolvers(boolean detectAllViewResolvers) {
<span style="white-space:pre">		</span>this.detectAllViewResolvers = detectAllViewResolvers;
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>public void setCleanupAfterInclude(boolean cleanupAfterInclude) {
<span style="white-space:pre">		</span>this.cleanupAfterInclude = cleanupAfterInclude;
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * 从DispatcherServlet的继承关系看：DispatcherServlet->FrameworkServlet
         *                                 ->HttpServletBean->HttpServlet
         * 初始化的过程是这样的HttpServletBean#init -> 
         *      FrameworkServlet#initServletBean -> DispatherServlet#onRefresh
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>@Override
<span style="white-space:pre">	</span>protected void onRefresh(ApplicationContext context) {
<span style="white-space:pre">		</span>initStrategies(context);
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * 初始化spring mvc的各种处理器
<span style="white-space:pre">	</span> * <p>May be overridden in subclasses in order to initialize further strategy objects.
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>protected void initStrategies(ApplicationContext context) {
<span style="white-space:pre">		</span>initMultipartResolver(context);
<span style="white-space:pre">		</span>initLocaleResolver(context);
<span style="white-space:pre">		</span>initThemeResolver(context);
<span style="white-space:pre">		</span>initHandlerMappings(context);
<span style="white-space:pre">		</span>initHandlerAdapters(context);
<span style="white-space:pre">		</span>initHandlerExceptionResolvers(context);
<span style="white-space:pre">		</span>initRequestToViewNameTranslator(context);
<span style="white-space:pre">		</span>initViewResolvers(context);
<span style="white-space:pre">		</span>initFlashMapManager(context);
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * 初始化MultipartResolver,如果没有，则不提供此处理器
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>private void initMultipartResolver(ApplicationContext context) {
<span style="white-space:pre">		</span>try {
<span style="white-space:pre">			</span>this.multipartResolver = context.getBean(MULTIPART_RESOLVER_BEAN_NAME, MultipartResolver.class);
<span style="white-space:pre">			</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">				</span>logger.debug("Using MultipartResolver [" + this.multipartResolver + "]");
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>catch (NoSuchBeanDefinitionException ex) {
<span style="white-space:pre">			</span>// Default is no multipart resolver.
<span style="white-space:pre">			</span>this.multipartResolver = null;
<span style="white-space:pre">			</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">				</span>logger.debug("Unable to locate MultipartResolver with name '" + MULTIPART_RESOLVER_BEAN_NAME +
<span style="white-space:pre">						</span>"': no multipart request handling provided");
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * 初始化LocaleResolver,如果没有，则使用默认的LocalResolver:AcceptHeaderLocaleResolver
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>private void initLocaleResolver(ApplicationContext context) {
<span style="white-space:pre">		</span>try {
<span style="white-space:pre">			</span>this.localeResolver = context.getBean(LOCALE_RESOLVER_BEAN_NAME, LocaleResolver.class);
<span style="white-space:pre">			</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">				</span>logger.debug("Using LocaleResolver [" + this.localeResolver + "]");
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>catch (NoSuchBeanDefinitionException ex) {
<span style="white-space:pre">			</span>// We need to use the default.
<span style="white-space:pre">			</span>this.localeResolver = getDefaultStrategy(context, LocaleResolver.class);
<span style="white-space:pre">			</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">				</span>logger.debug("Unable to locate LocaleResolver with name '" + LOCALE_RESOLVER_BEAN_NAME +
<span style="white-space:pre">						</span>"': using default [" + this.localeResolver + "]");
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * 初始化ThemeResolver,如果没有，
<span style="white-space:pre">	</span> * 则使用默认的ThemeResolver:FixedThemeResolver
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>private void initThemeResolver(ApplicationContext context) {
<span style="white-space:pre">		</span>try {
<span style="white-space:pre">			</span>this.themeResolver = context.getBean(THEME_RESOLVER_BEAN_NAME, ThemeResolver.class);
<span style="white-space:pre">			</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">				</span>logger.debug("Using ThemeResolver [" + this.themeResolver + "]");
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>catch (NoSuchBeanDefinitionException ex) {
<span style="white-space:pre">			</span>// We need to use the default.
<span style="white-space:pre">			</span>this.themeResolver = getDefaultStrategy(context, ThemeResolver.class);
<span style="white-space:pre">			</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">				</span>logger.debug(
<span style="white-space:pre">						</span>"Unable to locate ThemeResolver with name '" + THEME_RESOLVER_BEAN_NAME + "': using default [" +
<span style="white-space:pre">								</span>this.themeResolver + "]");
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * 初始化HandlerMapping
<span style="white-space:pre">	</span> * detectAllHandlerMappings=true时，加载所有的HandlerMapping，若为false时，加载指定的HandlerMapping
<span style="white-space:pre">	</span> * 如果都没有，则使用默认的:BeanNameUrlHandlerMapping、DefaultAnnotationHandlerMapping
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>private void initHandlerMappings(ApplicationContext context) {
<span style="white-space:pre">		</span>this.handlerMappings = null;


<span style="white-space:pre">		</span>if (this.detectAllHandlerMappings) {
<span style="white-space:pre">			</span>// Find all HandlerMappings in the ApplicationContext, including ancestor contexts.
<span style="white-space:pre">			</span>Map<String, HandlerMapping> matchingBeans =
<span style="white-space:pre">					</span>BeanFactoryUtils.beansOfTypeIncludingAncestors(context, HandlerMapping.class, true, false);
<span style="white-space:pre">			</span>if (!matchingBeans.isEmpty()) {
<span style="white-space:pre">				</span>this.handlerMappings = new ArrayList<HandlerMapping>(matchingBeans.values());
<span style="white-space:pre">				</span>// We keep HandlerMappings in sorted order.
<span style="white-space:pre">				</span>OrderComparator.sort(this.handlerMappings);
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>else {
<span style="white-space:pre">			</span>try {
<span style="white-space:pre">				</span>HandlerMapping hm = context.getBean(HANDLER_MAPPING_BEAN_NAME, HandlerMapping.class);
<span style="white-space:pre">				</span>this.handlerMappings = Collections.singletonList(hm);
<span style="white-space:pre">			</span>}
<span style="white-space:pre">			</span>catch (NoSuchBeanDefinitionException ex) {
<span style="white-space:pre">				</span>// Ignore, we'll add a default HandlerMapping later.
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}


<span style="white-space:pre">		</span>// Ensure we have at least one HandlerMapping, by registering
<span style="white-space:pre">		</span>// a default HandlerMapping if no other mappings are found.
<span style="white-space:pre">		</span>if (this.handlerMappings == null) {
<span style="white-space:pre">			</span>this.handlerMappings = getDefaultStrategies(context, HandlerMapping.class);
<span style="white-space:pre">			</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">				</span>logger.debug("No HandlerMappings found in servlet '" + getServletName() + "': using default");
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * 初始化HandlerAdapter
<span style="white-space:pre">	</span> * detectAllHandlerAdapters=true时，加载所有的HandlerAdapter，若为false时，加载指定的HandlerAdapter
<span style="white-space:pre">	</span> * 如果都没有，则使用默认的:HttpRequestHandlerAdapter、SimpleControllerHandlerAdapter、AnnotationMethodHandlerAdapter
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>private void initHandlerAdapters(ApplicationContext context) {
<span style="white-space:pre">		</span>this.handlerAdapters = null;


<span style="white-space:pre">		</span>if (this.detectAllHandlerAdapters) {
<span style="white-space:pre">			</span>// Find all HandlerAdapters in the ApplicationContext, including ancestor contexts.
<span style="white-space:pre">			</span>Map<String, HandlerAdapter> matchingBeans =
<span style="white-space:pre">					</span>BeanFactoryUtils.beansOfTypeIncludingAncestors(context, HandlerAdapter.class, true, false);
<span style="white-space:pre">			</span>if (!matchingBeans.isEmpty()) {
<span style="white-space:pre">				</span>this.handlerAdapters = new ArrayList<HandlerAdapter>(matchingBeans.values());
<span style="white-space:pre">				</span>// We keep HandlerAdapters in sorted order.
<span style="white-space:pre">				</span>OrderComparator.sort(this.handlerAdapters);
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>else {
<span style="white-space:pre">			</span>try {
<span style="white-space:pre">				</span>HandlerAdapter ha = context.getBean(HANDLER_ADAPTER_BEAN_NAME, HandlerAdapter.class);
<span style="white-space:pre">				</span>this.handlerAdapters = Collections.singletonList(ha);
<span style="white-space:pre">			</span>}
<span style="white-space:pre">			</span>catch (NoSuchBeanDefinitionException ex) {
<span style="white-space:pre">				</span>// Ignore, we'll add a default HandlerAdapter later.
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}


<span style="white-space:pre">		</span>// Ensure we have at least some HandlerAdapters, by registering
<span style="white-space:pre">		</span>// default HandlerAdapters if no other adapters are found.
<span style="white-space:pre">		</span>if (this.handlerAdapters == null) {
<span style="white-space:pre">			</span>this.handlerAdapters = getDefaultStrategies(context, HandlerAdapter.class);
<span style="white-space:pre">			</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">				</span>logger.debug("No HandlerAdapters found in servlet '" + getServletName() + "': using default");
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * 初始化HandlerExceptionResolvers
<span style="white-space:pre">	</span> * detectAllHandlerExceptionResolvers=true时，加载所有的HandlerExceptionResolvers，若为false时，加载指定的HandlerExceptionResolvers
<span style="white-space:pre">	</span> * 如果都没有，则使用默认的:AnnotationMethodHandlerExceptionResolver、ResponseStatusExceptionResolver、DefaultHandlerExceptionResolver
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>private void initHandlerExceptionResolvers(ApplicationContext context) {
<span style="white-space:pre">		</span>this.handlerExceptionResolvers = null;


<span style="white-space:pre">		</span>if (this.detectAllHandlerExceptionResolvers) {
<span style="white-space:pre">			</span>// Find all HandlerExceptionResolvers in the ApplicationContext, including ancestor contexts.
<span style="white-space:pre">			</span>Map<String, HandlerExceptionResolver> matchingBeans = BeanFactoryUtils
<span style="white-space:pre">					</span>.beansOfTypeIncludingAncestors(context, HandlerExceptionResolver.class, true, false);
<span style="white-space:pre">			</span>if (!matchingBeans.isEmpty()) {
<span style="white-space:pre">				</span>this.handlerExceptionResolvers = new ArrayList<HandlerExceptionResolver>(matchingBeans.values());
<span style="white-space:pre">				</span>// We keep HandlerExceptionResolvers in sorted order.
<span style="white-space:pre">				</span>OrderComparator.sort(this.handlerExceptionResolvers);
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>else {
<span style="white-space:pre">			</span>try {
<span style="white-space:pre">				</span>HandlerExceptionResolver her =
<span style="white-space:pre">						</span>context.getBean(HANDLER_EXCEPTION_RESOLVER_BEAN_NAME, HandlerExceptionResolver.class);
<span style="white-space:pre">				</span>this.handlerExceptionResolvers = Collections.singletonList(her);
<span style="white-space:pre">			</span>}
<span style="white-space:pre">			</span>catch (NoSuchBeanDefinitionException ex) {
<span style="white-space:pre">				</span>// Ignore, no HandlerExceptionResolver is fine too.
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}


<span style="white-space:pre">		</span>// Ensure we have at least some HandlerExceptionResolvers, by registering
<span style="white-space:pre">		</span>// default HandlerExceptionResolvers if no other resolvers are found.
<span style="white-space:pre">		</span>if (this.handlerExceptionResolvers == null) {
<span style="white-space:pre">			</span>this.handlerExceptionResolvers = getDefaultStrategies(context, HandlerExceptionResolver.class);
<span style="white-space:pre">			</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">				</span>logger.debug("No HandlerExceptionResolvers found in servlet '" + getServletName() + "': using default");
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * 初始化RequestToViewNameTranslator
<span style="white-space:pre">	</span> * 如果没有，则使用默认的:DefaultRequestToViewNameTranslator
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>private void initRequestToViewNameTranslator(ApplicationContext context) {
<span style="white-space:pre">		</span>try {
<span style="white-space:pre">			</span>this.viewNameTranslator =
<span style="white-space:pre">					</span>context.getBean(REQUEST_TO_VIEW_NAME_TRANSLATOR_BEAN_NAME, RequestToViewNameTranslator.class);
<span style="white-space:pre">			</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">				</span>logger.debug("Using RequestToViewNameTranslator [" + this.viewNameTranslator + "]");
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>catch (NoSuchBeanDefinitionException ex) {
<span style="white-space:pre">			</span>// We need to use the default.
<span style="white-space:pre">			</span>this.viewNameTranslator = getDefaultStrategy(context, RequestToViewNameTranslator.class);
<span style="white-space:pre">			</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">				</span>logger.debug("Unable to locate RequestToViewNameTranslator with name '" +
<span style="white-space:pre">						</span>REQUEST_TO_VIEW_NAME_TRANSLATOR_BEAN_NAME + "': using default [" + this.viewNameTranslator +
<span style="white-space:pre">						</span>"]");
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">	</span>}


        /**
<span style="white-space:pre">	</span> * 初始化ViewResolver
<span style="white-space:pre">	</span> * detectAllViewResolvers=true时，加载所有的ViewResolver，若为false时，加载指定的ViewResolver
<span style="white-space:pre">	</span> * 如果都没有，则使用默认的:InternalResourceViewResolver
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>private void initViewResolvers(ApplicationContext context) {
<span style="white-space:pre">		</span>this.viewResolvers = null;


<span style="white-space:pre">		</span>if (this.detectAllViewResolvers) {
<span style="white-space:pre">			</span>// Find all ViewResolvers in the ApplicationContext, including ancestor contexts.
<span style="white-space:pre">			</span>Map<String, ViewResolver> matchingBeans =
<span style="white-space:pre">					</span>BeanFactoryUtils.beansOfTypeIncludingAncestors(context, ViewResolver.class, true, false);
<span style="white-space:pre">			</span>if (!matchingBeans.isEmpty()) {
<span style="white-space:pre">				</span>this.viewResolvers = new ArrayList<ViewResolver>(matchingBeans.values());
<span style="white-space:pre">				</span>// We keep ViewResolvers in sorted order.
<span style="white-space:pre">				</span>OrderComparator.sort(this.viewResolvers);
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>else {
<span style="white-space:pre">			</span>try {
<span style="white-space:pre">				</span>ViewResolver vr = context.getBean(VIEW_RESOLVER_BEAN_NAME, ViewResolver.class);
<span style="white-space:pre">				</span>this.viewResolvers = Collections.singletonList(vr);
<span style="white-space:pre">			</span>}
<span style="white-space:pre">			</span>catch (NoSuchBeanDefinitionException ex) {
<span style="white-space:pre">				</span>// Ignore, we'll add a default ViewResolver later.
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}


<span style="white-space:pre">		</span>// Ensure we have at least one ViewResolver, by registering
<span style="white-space:pre">		</span>// a default ViewResolver if no other resolvers are found.
<span style="white-space:pre">		</span>if (this.viewResolvers == null) {
<span style="white-space:pre">			</span>this.viewResolvers = getDefaultStrategies(context, ViewResolver.class);
<span style="white-space:pre">			</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">				</span>logger.debug("No ViewResolvers found in servlet '" + getServletName() + "': using default");
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * 初始化FlashMapManager
<span style="white-space:pre">	</span> * 如果没有，则使用默认的:SessionFlashMapManager
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>private void initFlashMapManager(ApplicationContext context) {
<span style="white-space:pre">		</span>try {
<span style="white-space:pre">			</span>this.flashMapManager =
<span style="white-space:pre">					</span>context.getBean(FLASH_MAP_MANAGER_BEAN_NAME, FlashMapManager.class);
<span style="white-space:pre">			</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">				</span>logger.debug("Using FlashMapManager [" + this.flashMapManager + "]");
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>catch (NoSuchBeanDefinitionException ex) {
<span style="white-space:pre">			</span>// We need to use the default.
<span style="white-space:pre">			</span>this.flashMapManager = getDefaultStrategy(context, FlashMapManager.class);
<span style="white-space:pre">			</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">				</span>logger.debug("Unable to locate FlashMapManager with name '" +
<span style="white-space:pre">						</span>FLASH_MAP_MANAGER_BEAN_NAME + "': using default [" + this.flashMapManager + "]");
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * 获取ThemeSource
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>public final ThemeSource getThemeSource() {
<span style="white-space:pre">		</span>if (getWebApplicationContext() instanceof ThemeSource) {
<span style="white-space:pre">			</span>return (ThemeSource) getWebApplicationContext();
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>else {
<span style="white-space:pre">			</span>return null;
<span style="white-space:pre">		</span>}
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * 获取MulitpartResolver
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>public final MultipartResolver getMultipartResolver() {
<span style="white-space:pre">		</span>return this.multipartResolver;
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * 获取默认的处理器.
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>protected <T> T getDefaultStrategy(ApplicationContext context, Class<T> strategyInterface) {
<span style="white-space:pre">		</span>List<T> strategies = getDefaultStrategies(context, strategyInterface);
<span style="white-space:pre">		</span>if (strategies.size() != 1) {
<span style="white-space:pre">			</span>throw new BeanInitializationException(
<span style="white-space:pre">					</span>"DispatcherServlet needs exactly 1 strategy for interface [" + strategyInterface.getName() + "]");
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>return strategies.get(0);
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * 获取默认配置.
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>@SuppressWarnings("unchecked")
<span style="white-space:pre">	</span>protected <T> List<T> getDefaultStrategies(ApplicationContext context, Class<T> strategyInterface) {
<span style="white-space:pre">		</span>String key = strategyInterface.getName();
                // 从配置文件中获取类名
<span style="white-space:pre">		</span>String value = defaultStrategies.getProperty(key);
<span style="white-space:pre">		</span>if (value != null) {
                        // 分割
<span style="white-space:pre">			</span>String[] classNames = StringUtils.commaDelimitedListToStringArray(value);
<span style="white-space:pre">			</span>List<T> strategies = new ArrayList<T>(classNames.length);
<span style="white-space:pre">			</span>for (String className : classNames) {
<span style="white-space:pre">				</span>try {
<span style="white-space:pre">					</span>Class<?> clazz = ClassUtils.forName(className, DispatcherServlet.class.getClassLoader());
                                        // 创建bean
<span style="white-space:pre">					</span>Object strategy = createDefaultStrategy(context, clazz);
<span style="white-space:pre">					</span>strategies.add((T) strategy);
<span style="white-space:pre">				</span>}
<span style="white-space:pre">				</span>catch (ClassNotFoundException ex) {
<span style="white-space:pre">					</span>throw new BeanInitializationException(
<span style="white-space:pre">							</span>"Could not find DispatcherServlet's default strategy class [" + className +
<span style="white-space:pre">									</span>"] for interface [" + key + "]", ex);
<span style="white-space:pre">				</span>}
<span style="white-space:pre">				</span>catch (LinkageError err) {
<span style="white-space:pre">					</span>throw new BeanInitializationException(
<span style="white-space:pre">							</span>"Error loading DispatcherServlet's default strategy class [" + className +
<span style="white-space:pre">									</span>"] for interface [" + key + "]: problem with class file or dependent class", err);
<span style="white-space:pre">				</span>}
<span style="white-space:pre">			</span>}
<span style="white-space:pre">			</span>return strategies;
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>else {
<span style="white-space:pre">			</span>return new LinkedList<T>();
<span style="white-space:pre">		</span>}
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * 创建bean.
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>protected Object createDefaultStrategy(ApplicationContext context, Class<?> clazz) {
<span style="white-space:pre">		</span>return context.getAutowireCapableBeanFactory().createBean(clazz);
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * doService是一个调度方法，每一个请求发生时，先执行此方法
<span style="white-space:pre">	</span> * for the actual dispatching.
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>@Override
<span style="white-space:pre">	</span>protected void doService(HttpServletRequest request, HttpServletResponse response) throws Exception {
<span style="white-space:pre">		</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">			</span>String requestUri = urlPathHelper.getRequestUri(request);
<span style="white-space:pre">			</span>logger.debug("DispatcherServlet with name '" + getServletName() + "' processing " + request.getMethod() +
<span style="white-space:pre">					</span>" request for [" + requestUri + "]");
<span style="white-space:pre">		</span>}


<span style="white-space:pre">		</span>// 是否存在客户当次请求信息
<span style="white-space:pre">		</span>Map<String, Object> attributesSnapshot = null;
<span style="white-space:pre">		</span>if (WebUtils.isIncludeRequest(request)) { // 判断是否为转发请求
<span style="white-space:pre">			</span>logger.debug("Taking snapshot of request attributes before include");
<span style="white-space:pre">			</span>attributesSnapshot = new HashMap<String, Object>();
<span style="white-space:pre">			</span>Enumeration<?> attrNames = request.getAttributeNames();
<span style="white-space:pre">			</span>while (attrNames.hasMoreElements()) {
<span style="white-space:pre">				</span>String attrName = (String) attrNames.nextElement();
<span style="white-space:pre">				</span>if (this.cleanupAfterInclude || attrName.startsWith("org.springframework.web.servlet")) {
<span style="white-space:pre">					</span>attributesSnapshot.put(attrName, request.getAttribute(attrName));
<span style="white-space:pre">				</span>}
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}


<span style="white-space:pre">		</span>// 设置属性
<span style="white-space:pre">		</span>request.setAttribute(WEB_APPLICATION_CONTEXT_ATTRIBUTE, getWebApplicationContext());
<span style="white-space:pre">		</span>request.setAttribute(LOCALE_RESOLVER_ATTRIBUTE, this.localeResolver);
<span style="white-space:pre">		</span>request.setAttribute(THEME_RESOLVER_ATTRIBUTE, this.themeResolver);
<span style="white-space:pre">		</span>request.setAttribute(THEME_SOURCE_ATTRIBUTE, getThemeSource());


<span style="white-space:pre">		</span>FlashMap inputFlashMap = this.flashMapManager.retrieveAndUpdate(request, response);
<span style="white-space:pre">		</span>if (inputFlashMap != null) {
<span style="white-space:pre">			</span>request.setAttribute(INPUT_FLASH_MAP_ATTRIBUTE, Collections.unmodifiableMap(inputFlashMap));
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>request.setAttribute(OUTPUT_FLASH_MAP_ATTRIBUTE, new FlashMap());
<span style="white-space:pre">		</span>request.setAttribute(FLASH_MAP_MANAGER_ATTRIBUTE, this.flashMapManager);


<span style="white-space:pre">		</span>try {
                        // 分发
<span style="white-space:pre">			</span>doDispatch(request, response);
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>finally {
<span style="white-space:pre">			</span>// 报错参数在之后的转发中.
<span style="white-space:pre">			</span>if (attributesSnapshot != null) {
<span style="white-space:pre">				</span>restoreAttributesAfterInclude(request, attributesSnapshot);
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * Process the actual dispatching to the handler.
<span style="white-space:pre">	</span> * <p>The handler will be obtained by applying the servlet's HandlerMappings in order.
<span style="white-space:pre">	</span> * The HandlerAdapter will be obtained by querying the servlet's installed HandlerAdapters
<span style="white-space:pre">	</span> * to find the first that supports the handler class.
<span style="white-space:pre">	</span> * <p>All HTTP methods are handled by this method. It's up to HandlerAdapters or handlers
<span style="white-space:pre">	</span> * themselves to decide which methods are acceptable.
<span style="white-space:pre">	</span> * @param request current HTTP request
<span style="white-space:pre">	</span> * @param response current HTTP response
<span style="white-space:pre">	</span> * @throws Exception in case of any kind of processing failure
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>protected void doDispatch(HttpServletRequest request, HttpServletResponse response) throws Exception {
<span style="white-space:pre">		</span>HttpServletRequest processedRequest = request;
<span style="white-space:pre">		</span>HandlerExecutionChain mappedHandler = null;
<span style="white-space:pre">		</span>int interceptorIndex = -1;


<span style="white-space:pre">		</span>try {
<span style="white-space:pre">			</span>ModelAndView mv;
<span style="white-space:pre">			</span>boolean errorView = false;


<span style="white-space:pre">			</span>try {
                                // 检查是否是请求是否是multipart（如文件上传），如果是将通过MultipartResolver解析
<span style="white-space:pre">				</span>processedRequest = checkMultipart(request);


<span style="white-space:pre">				</span>// 请求到处理器（页面控制器）的映射，通过HandlerMapping进行映射.
<span style="white-space:pre">				</span>mappedHandler = getHandler(processedRequest, false);
<span style="white-space:pre">				</span>if (mappedHandler == null || mappedHandler.getHandler() == null) {
<span style="white-space:pre">					</span>noHandlerFound(processedRequest, response);
<span style="white-space:pre">					</span>return;
<span style="white-space:pre">				</span>}


<span style="white-space:pre">				</span>// 处理器适配，即将我们的处理器包装成相应的适配器（从而支持多种类型的处理器）  
<span style="white-space:pre">				</span>HandlerAdapter ha = getHandlerAdapter(mappedHandler.getHandler());


                                // Not Modified缓存支持.
<span style="white-space:pre">				</span>String method = request.getMethod();
<span style="white-space:pre">				</span>boolean isGet = "GET".equals(method);
<span style="white-space:pre">				</span>if (isGet || "HEAD".equals(method)) {
<span style="white-space:pre">					</span>long lastModified = ha.getLastModified(request, mappedHandler.getHandler());
<span style="white-space:pre">					</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">						</span>String requestUri = urlPathHelper.getRequestUri(request);
<span style="white-space:pre">						</span>logger.debug("Last-Modified value for [" + requestUri + "] is: " + lastModified);
<span style="white-space:pre">					</span>}
<span style="white-space:pre">					</span>if (new ServletWebRequest(request, response).checkNotModified(lastModified) && isGet) {
<span style="white-space:pre">						</span>return;
<span style="white-space:pre">					</span>}
<span style="white-space:pre">				</span>}


<span style="white-space:pre">				</span>// 执行处理器相关的拦截器的预处理（HandlerInterceptor.preHandle）.
<span style="white-space:pre">				</span>HandlerInterceptor[] interceptors = mappedHandler.getInterceptors();
<span style="white-space:pre">				</span>if (interceptors != null) {
<span style="white-space:pre">					</span>for (int i = 0; i < interceptors.length; i++) {
<span style="white-space:pre">						</span>HandlerInterceptor interceptor = interceptors[i];
<span style="white-space:pre">						</span>if (!interceptor.preHandle(processedRequest, response, mappedHandler.getHandler())) {
<span style="white-space:pre">							</span>triggerAfterCompletion(mappedHandler, interceptorIndex, processedRequest, response, null);
<span style="white-space:pre">							</span>return;
<span style="white-space:pre">						</span>}
<span style="white-space:pre">						</span>interceptorIndex = i;
<span style="white-space:pre">					</span>}
<span style="white-space:pre">				</span>}


<span style="white-space:pre">				</span>// 由适配器执行处理器（调用处理器相应功能处理方法）.
<span style="white-space:pre">				</span>mv = ha.handle(processedRequest, response, mappedHandler.getHandler());


<span style="white-space:pre">				</span>// 如果mv==null，设置为默认的
<span style="white-space:pre">				</span>if (mv != null && !mv.hasView()) {
<span style="white-space:pre">					</span>mv.setViewName(getDefaultViewName(request));
<span style="white-space:pre">				</span>}


<span style="white-space:pre">				</span>// 执行处理器相关的拦截器的后处理（HandlerInterceptor.postHandle）
<span style="white-space:pre">				</span>if (interceptors != null) {
<span style="white-space:pre">					</span>for (int i = interceptors.length - 1; i >= 0; i--) {
<span style="white-space:pre">						</span>HandlerInterceptor interceptor = interceptors[i];
<span style="white-space:pre">						</span>interceptor.postHandle(processedRequest, response, mappedHandler.getHandler(), mv);
<span style="white-space:pre">					</span>}
<span style="white-space:pre">				</span>}
<span style="white-space:pre">			</span>}
<span style="white-space:pre">			</span>catch (ModelAndViewDefiningException ex) {
<span style="white-space:pre">				</span>logger.debug("ModelAndViewDefiningException encountered", ex);
<span style="white-space:pre">				</span>mv = ex.getModelAndView();
<span style="white-space:pre">			</span>}
<span style="white-space:pre">			</span>catch (Exception ex) {
<span style="white-space:pre">				</span>Object handler = (mappedHandler != null ? mappedHandler.getHandler() : null);
<span style="white-space:pre">				</span>mv = processHandlerException(processedRequest, response, handler, ex);
<span style="white-space:pre">				</span>errorView = (mv != null);
<span style="white-space:pre">			</span>}


<span style="white-space:pre">			</span>// 解析视图并进行视图的渲染
<span style="white-space:pre">			</span>if (mv != null && !mv.wasCleared()) {
<span style="white-space:pre">				</span>render(mv, processedRequest, response);
<span style="white-space:pre">				</span>if (errorView) {
<span style="white-space:pre">					</span>WebUtils.clearErrorRequestAttributes(request);
<span style="white-space:pre">				</span>}
<span style="white-space:pre">			</span>}
<span style="white-space:pre">			</span>else {
<span style="white-space:pre">				</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">					</span>logger.debug("Null ModelAndView returned to DispatcherServlet with name '" + getServletName() +
<span style="white-space:pre">							</span>"': assuming HandlerAdapter completed request handling");
<span style="white-space:pre">				</span>}
<span style="white-space:pre">			</span>}


<span style="white-space:pre">			</span>// T执行处理器相关的拦截器的完成后处理（HandlerInterceptor.afterCompletion）
<span style="white-space:pre">			</span>triggerAfterCompletion(mappedHandler, interceptorIndex, processedRequest, response, null);
<span style="white-space:pre">		</span>}


<span style="white-space:pre">		</span>catch (Exception ex) {
<span style="white-space:pre">			</span>// Trigger after-completion for thrown exception.
<span style="white-space:pre">			</span>triggerAfterCompletion(mappedHandler, interceptorIndex, processedRequest, response, ex);
<span style="white-space:pre">			</span>throw ex;
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>catch (Error err) {
<span style="white-space:pre">			</span>ServletException ex = new NestedServletException("Handler processing failed", err);
<span style="white-space:pre">			</span>// Trigger after-completion for thrown exception.
<span style="white-space:pre">			</span>triggerAfterCompletion(mappedHandler, interceptorIndex, processedRequest, response, ex);
<span style="white-space:pre">			</span>throw ex;
<span style="white-space:pre">		</span>}


<span style="white-space:pre">		</span>finally {
<span style="white-space:pre">			</span>// Clean up any resources used by a multipart request.
<span style="white-space:pre">			</span>if (processedRequest != request) {
<span style="white-space:pre">				</span>cleanupMultipart(processedRequest);
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * Build a LocaleContext for the given request, exposing the request's primary locale as current locale.
<span style="white-space:pre">	</span> * <p>The default implementation uses the dispatcher's LocaleResolver to obtain the current locale,
<span style="white-space:pre">	</span> * which might change during a request.
<span style="white-space:pre">	</span> * @param request current HTTP request
<span style="white-space:pre">	</span> * @return the corresponding LocaleContext
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>@Override
<span style="white-space:pre">	</span>protected LocaleContext buildLocaleContext(final HttpServletRequest request) {
<span style="white-space:pre">		</span>return new LocaleContext() {
<span style="white-space:pre">			</span>public Locale getLocale() {
<span style="white-space:pre">				</span>return localeResolver.resolveLocale(request);
<span style="white-space:pre">			</span>}
<span style="white-space:pre">			</span>@Override
<span style="white-space:pre">			</span>public String toString() {
<span style="white-space:pre">				</span>return getLocale().toString();
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>};
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * 检查是否是请求是否是multipart（如文件上传），如果是将通过MultipartResolver解析.
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>protected HttpServletRequest checkMultipart(HttpServletRequest request) throws MultipartException {
<span style="white-space:pre">		</span>if (this.multipartResolver != null && this.multipartResolver.isMultipart(request)) {
<span style="white-space:pre">			</span>if (request instanceof MultipartHttpServletRequest) {
<span style="white-space:pre">				</span>logger.debug("Request is already a MultipartHttpServletRequest - if not in a forward, " +
<span style="white-space:pre">						</span>"this typically results from an additional MultipartFilter in web.xml");
<span style="white-space:pre">			</span>}
<span style="white-space:pre">			</span>else {
<span style="white-space:pre">				</span>return this.multipartResolver.resolveMultipart(request);
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>// If not returned before: return original request.
<span style="white-space:pre">		</span>return request;
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * Clean up any resources used by the given multipart request (if any).
<span style="white-space:pre">	</span> * @param request current HTTP request
<span style="white-space:pre">	</span> * @see MultipartResolver#cleanupMultipart
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>protected void cleanupMultipart(HttpServletRequest request) {
<span style="white-space:pre">		</span>if (request instanceof MultipartHttpServletRequest) {
<span style="white-space:pre">			</span>this.multipartResolver.cleanupMultipart((MultipartHttpServletRequest) request);
<span style="white-space:pre">		</span>}
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * Return the HandlerExecutionChain for this request. Try all handler mappings in order.
<span style="white-space:pre">	</span> * @param request current HTTP request
<span style="white-space:pre">	</span> * @param cache whether to cache the HandlerExecutionChain in a request attribute
<span style="white-space:pre">	</span> * @return the HandlerExecutionChain, or <code>null</code> if no handler could be found
<span style="white-space:pre">	</span> * @deprecated as of Spring 3.0.4, in favor of {@link #getHandler(javax.servlet.http.HttpServletRequest)},
<span style="white-space:pre">	</span> * with this method's cache attribute now effectively getting ignored
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>@Deprecated
<span style="white-space:pre">	</span>protected HandlerExecutionChain getHandler(HttpServletRequest request, boolean cache) throws Exception {
<span style="white-space:pre">		</span>return getHandler(request);
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * Return the HandlerExecutionChain for this request.
<span style="white-space:pre">	</span> * <p>Tries all handler mappings in order.
<span style="white-space:pre">	</span> * @param request current HTTP request
<span style="white-space:pre">	</span> * @return the HandlerExecutionChain, or <code>null</code> if no handler could be found
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>protected HandlerExecutionChain getHandler(HttpServletRequest request) throws Exception {
<span style="white-space:pre">		</span>for (HandlerMapping hm : this.handlerMappings) {
<span style="white-space:pre">			</span>if (logger.isTraceEnabled()) {
<span style="white-space:pre">				</span>logger.trace(
<span style="white-space:pre">						</span>"Testing handler map [" + hm + "] in DispatcherServlet with name '" + getServletName() + "'");
<span style="white-space:pre">			</span>}
<span style="white-space:pre">			</span>HandlerExecutionChain handler = hm.getHandler(request);
<span style="white-space:pre">			</span>if (handler != null) {
<span style="white-space:pre">				</span>return handler;
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>return null;
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * No handler found -> set appropriate HTTP response status.
<span style="white-space:pre">	</span> * @param request current HTTP request
<span style="white-space:pre">	</span> * @param response current HTTP response
<span style="white-space:pre">	</span> * @throws Exception if preparing the response failed
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>protected void noHandlerFound(HttpServletRequest request, HttpServletResponse response) throws Exception {
<span style="white-space:pre">		</span>if (pageNotFoundLogger.isWarnEnabled()) {
<span style="white-space:pre">			</span>String requestUri = urlPathHelper.getRequestUri(request);
<span style="white-space:pre">			</span>pageNotFoundLogger.warn("No mapping found for HTTP request with URI [" + requestUri +
<span style="white-space:pre">					</span>"] in DispatcherServlet with name '" + getServletName() + "'");
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>response.sendError(HttpServletResponse.SC_NOT_FOUND);
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * Return the HandlerAdapter for this handler object.
<span style="white-space:pre">	</span> * @param handler the handler object to find an adapter for
<span style="white-space:pre">	</span> * @throws ServletException if no HandlerAdapter can be found for the handler. This is a fatal error.
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>protected HandlerAdapter getHandlerAdapter(Object handler) throws ServletException {
<span style="white-space:pre">		</span>for (HandlerAdapter ha : this.handlerAdapters) {
<span style="white-space:pre">			</span>if (logger.isTraceEnabled()) {
<span style="white-space:pre">				</span>logger.trace("Testing handler adapter [" + ha + "]");
<span style="white-space:pre">			</span>}
<span style="white-space:pre">			</span>if (ha.supports(handler)) {
<span style="white-space:pre">				</span>return ha;
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>throw new ServletException("No adapter for handler [" + handler +
<span style="white-space:pre">				</span>"]: Does your handler implement a supported interface like Controller?");
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * Determine an error ModelAndView via the registered HandlerExceptionResolvers.
<span style="white-space:pre">	</span> * @param request current HTTP request
<span style="white-space:pre">	</span> * @param response current HTTP response
<span style="white-space:pre">	</span> * @param handler the executed handler, or <code>null</code> if none chosen at the time of the exception
<span style="white-space:pre">	</span> * (for example, if multipart resolution failed)
<span style="white-space:pre">	</span> * @param ex the exception that got thrown during handler execution
<span style="white-space:pre">	</span> * @return a corresponding ModelAndView to forward to
<span style="white-space:pre">	</span> * @throws Exception if no error ModelAndView found
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>protected ModelAndView processHandlerException(HttpServletRequest request, HttpServletResponse response,
<span style="white-space:pre">			</span>Object handler, Exception ex) throws Exception {


<span style="white-space:pre">		</span>// Check registered HandlerExceptionResolvers...
<span style="white-space:pre">		</span>ModelAndView exMv = null;
<span style="white-space:pre">		</span>for (HandlerExceptionResolver handlerExceptionResolver : this.handlerExceptionResolvers) {
<span style="white-space:pre">			</span>exMv = handlerExceptionResolver.resolveException(request, response, handler, ex);
<span style="white-space:pre">			</span>if (exMv != null) {
<span style="white-space:pre">				</span>break;
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>if (exMv != null) {
<span style="white-space:pre">			</span>if (exMv.isEmpty()) {
<span style="white-space:pre">				</span>return null;
<span style="white-space:pre">			</span>}
<span style="white-space:pre">			</span>// We might still need view name translation for a plain error model...
<span style="white-space:pre">			</span>if (!exMv.hasView()) {
<span style="white-space:pre">				</span>exMv.setViewName(getDefaultViewName(request));
<span style="white-space:pre">			</span>}
<span style="white-space:pre">			</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">				</span>logger.debug("Handler execution resulted in exception - forwarding to resolved error view: " + exMv, ex);
<span style="white-space:pre">			</span>}
<span style="white-space:pre">			</span>WebUtils.exposeErrorRequestAttributes(request, ex, getServletName());
<span style="white-space:pre">			</span>return exMv;
<span style="white-space:pre">		</span>}


<span style="white-space:pre">		</span>throw ex;
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * Render the given ModelAndView.
<span style="white-space:pre">	</span> * <p>This is the last stage in handling a request. It may involve resolving the view by name.
<span style="white-space:pre">	</span> * @param mv the ModelAndView to render
<span style="white-space:pre">	</span> * @param request current HTTP servlet request
<span style="white-space:pre">	</span> * @param response current HTTP servlet response
<span style="white-space:pre">	</span> * @throws ServletException if view is missing or cannot be resolved
<span style="white-space:pre">	</span> * @throws Exception if there's a problem rendering the view
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>protected void render(ModelAndView mv, HttpServletRequest request, HttpServletResponse response) throws Exception {
<span style="white-space:pre">		</span>// Determine locale for request and apply it to the response.
<span style="white-space:pre">		</span>Locale locale = this.localeResolver.resolveLocale(request);
<span style="white-space:pre">		</span>response.setLocale(locale);


<span style="white-space:pre">		</span>View view;
<span style="white-space:pre">		</span>if (mv.isReference()) {
<span style="white-space:pre">			</span>// We need to resolve the view name.
<span style="white-space:pre">			</span>view = resolveViewName(mv.getViewName(), mv.getModelInternal(), locale, request);
<span style="white-space:pre">			</span>if (view == null) {
<span style="white-space:pre">				</span>throw new ServletException(
<span style="white-space:pre">						</span>"Could not resolve view with name '" + mv.getViewName() + "' in servlet with name '" +
<span style="white-space:pre">								</span>getServletName() + "'");
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>else {
<span style="white-space:pre">			</span>// No need to lookup: the ModelAndView object contains the actual View object.
<span style="white-space:pre">			</span>view = mv.getView();
<span style="white-space:pre">			</span>if (view == null) {
<span style="white-space:pre">				</span>throw new ServletException("ModelAndView [" + mv + "] neither contains a view name nor a " +
<span style="white-space:pre">						</span>"View object in servlet with name '" + getServletName() + "'");
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}


<span style="white-space:pre">		</span>// Delegate to the View object for rendering.
<span style="white-space:pre">		</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">			</span>logger.debug("Rendering view [" + view + "] in DispatcherServlet with name '" + getServletName() + "'");
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>view.render(mv.getModelInternal(), request, response);
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * Translate the supplied request into a default view name.
<span style="white-space:pre">	</span> * @param request current HTTP servlet request
<span style="white-space:pre">	</span> * @return the view name (or <code>null</code> if no default found)
<span style="white-space:pre">	</span> * @throws Exception if view name translation failed
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>protected String getDefaultViewName(HttpServletRequest request) throws Exception {
<span style="white-space:pre">		</span>return this.viewNameTranslator.getViewName(request);
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * Resolve the given view name into a View object (to be rendered).
<span style="white-space:pre">	</span> * <p>The default implementations asks all ViewResolvers of this dispatcher.
<span style="white-space:pre">	</span> * Can be overridden for custom resolution strategies, potentially based on
<span style="white-space:pre">	</span> * specific model attributes or request parameters.
<span style="white-space:pre">	</span> * @param viewName the name of the view to resolve
<span style="white-space:pre">	</span> * @param model the model to be passed to the view
<span style="white-space:pre">	</span> * @param locale the current locale
<span style="white-space:pre">	</span> * @param request current HTTP servlet request
<span style="white-space:pre">	</span> * @return the View object, or <code>null</code> if none found
<span style="white-space:pre">	</span> * @throws Exception if the view cannot be resolved
<span style="white-space:pre">	</span> * (typically in case of problems creating an actual View object)
<span style="white-space:pre">	</span> * @see ViewResolver#resolveViewName
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>protected View resolveViewName(String viewName, Map<String, Object> model, Locale locale,
<span style="white-space:pre">			</span>HttpServletRequest request) throws Exception {


<span style="white-space:pre">		</span>for (ViewResolver viewResolver : this.viewResolvers) {
<span style="white-space:pre">			</span>View view = viewResolver.resolveViewName(viewName, locale);
<span style="white-space:pre">			</span>if (view != null) {
<span style="white-space:pre">				</span>return view;
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>return null;
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * Trigger afterCompletion callbacks on the mapped HandlerInterceptors.
<span style="white-space:pre">	</span> * Will just invoke afterCompletion for all interceptors whose preHandle invocation
<span style="white-space:pre">	</span> * has successfully completed and returned true.
<span style="white-space:pre">	</span> * @param mappedHandler the mapped HandlerExecutionChain
<span style="white-space:pre">	</span> * @param interceptorIndex index of last interceptor that successfully completed
<span style="white-space:pre">	</span> * @param ex Exception thrown on handler execution, or <code>null</code> if none
<span style="white-space:pre">	</span> * @see HandlerInterceptor#afterCompletion
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>private void triggerAfterCompletion(HandlerExecutionChain mappedHandler,
<span style="white-space:pre">			</span>int interceptorIndex,
<span style="white-space:pre">			</span>HttpServletRequest request,
<span style="white-space:pre">			</span>HttpServletResponse response,
<span style="white-space:pre">			</span>Exception ex) throws Exception {


<span style="white-space:pre">		</span>// Apply afterCompletion methods of registered interceptors.
<span style="white-space:pre">		</span>if (mappedHandler != null) {
<span style="white-space:pre">			</span>HandlerInterceptor[] interceptors = mappedHandler.getInterceptors();
<span style="white-space:pre">			</span>if (interceptors != null) {
<span style="white-space:pre">				</span>for (int i = interceptorIndex; i >= 0; i--) {
<span style="white-space:pre">					</span>HandlerInterceptor interceptor = interceptors[i];
<span style="white-space:pre">					</span>try {
<span style="white-space:pre">						</span>interceptor.afterCompletion(request, response, mappedHandler.getHandler(), ex);
<span style="white-space:pre">					</span>}
<span style="white-space:pre">					</span>catch (Throwable ex2) {
<span style="white-space:pre">						</span>logger.error("HandlerInterceptor.afterCompletion threw exception", ex2);
<span style="white-space:pre">					</span>}
<span style="white-space:pre">				</span>}
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">	</span>}


<span style="white-space:pre">	</span>/**
<span style="white-space:pre">	</span> * Restore the request attributes after an include.
<span style="white-space:pre">	</span> * @param request current HTTP request
<span style="white-space:pre">	</span> * @param attributesSnapshot the snapshot of the request attributes before the include
<span style="white-space:pre">	</span> */
<span style="white-space:pre">	</span>private void restoreAttributesAfterInclude(HttpServletRequest request, Map<?,?> attributesSnapshot) {
<span style="white-space:pre">		</span>logger.debug("Restoring snapshot of request attributes after include");


<span style="white-space:pre">		</span>// Need to copy into separate Collection here, to avoid side effects
<span style="white-space:pre">		</span>// on the Enumeration when removing attributes.
<span style="white-space:pre">		</span>Set<String> attrsToCheck = new HashSet<String>();
<span style="white-space:pre">		</span>Enumeration<?> attrNames = request.getAttributeNames();
<span style="white-space:pre">		</span>while (attrNames.hasMoreElements()) {
<span style="white-space:pre">			</span>String attrName = (String) attrNames.nextElement();
<span style="white-space:pre">			</span>if (this.cleanupAfterInclude || attrName.startsWith("org.springframework.web.servlet")) {
<span style="white-space:pre">				</span>attrsToCheck.add(attrName);
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}


<span style="white-space:pre">		</span>// Iterate over the attributes to check, restoring the original value
<span style="white-space:pre">		</span>// or removing the attribute, respectively, if appropriate.
<span style="white-space:pre">		</span>for (String attrName : attrsToCheck) {
<span style="white-space:pre">			</span>Object attrValue = attributesSnapshot.get(attrName);
<span style="white-space:pre">			</span>if (attrValue == null){
<span style="white-space:pre">				</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">					</span>logger.debug("Removing attribute [" + attrName + "] after include");
<span style="white-space:pre">				</span>}
<span style="white-space:pre">				</span>request.removeAttribute(attrName);
<span style="white-space:pre">			</span>}
<span style="white-space:pre">			</span>else if (attrValue != request.getAttribute(attrName)) {
<span style="white-space:pre">				</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">					</span>logger.debug("Restoring original value of attribute [" + attrName + "] after include");
<span style="white-space:pre">				</span>}
<span style="white-space:pre">				</span>request.setAttribute(attrName, attrValue);
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">	</span>}


}