1.SpringMVC的执行流程

1.what

springMVC是spring对web中变现层的封装
主要包括：Model[javabean]、view[jsp等]、Controller[servlet控制]

2.why

利用springMVC对变现层进行封装可以极大提高开发的效率

3.流程

4.code

1. web.xml

  <!--配置前端控制器-->
  <servlet>
    <servlet-name>dispatcherServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:springmvc.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>dispatcherServlet</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>

  <!--配置解决中文乱码的过滤器-->
  <filter>
    <filter-name>characterEncodingFilter</filter-name>
    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
    <init-param>
      <param-name>encoding</param-name>
      <param-value>UTF-8</param-value>
    </init-param>
  </filter>
  <filter-mapping>
    <filter-name>characterEncodingFilter</filter-name>
    <url-pattern>/*
  

2.xml配置文件

    <!-- 开启注解扫描 -->
    <context:component-scan base-package="cn.itcast"/>

    <!-- 视图解析器对象 -->
    <bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/pages/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <!--配置自定义类型转换器-->
    <bean id="conversionService" class="org.springframework.context.support.ConversionServiceFactoryBean">
        <property name="converters">
            <set>
                <bean class="cn.itcast.utils.StringToDateConverter"/>
            </set>
        </property>
    </bean>


    <!-- 开启SpringMVC框架注解的支持 -->
    <mvc:annotation-driven conversion-service="conversionService"/>

3. 请求参数的绑定

* 请求参数绑定
 */
@Controller
@RequestMapping("/param")
public class ParamController {

    /**
     * 请求参数绑定入门
     * @return
     */
    @RequestMapping("/testParam")
    public String testParam(String username,String password){
        System.out.println("执行了...");
        System.out.println("用户名："+username);
        System.out.println("密码："+password);
        return "success";
    }

    /**
     * 请求参数绑定把数据封装到JavaBean的类中
     * @return
     */
    @RequestMapping("/saveAccount")
    public String saveAccount(Account account){
        System.out.println("执行了...");
        System.out.println(account);
        return "success";
    }


    /**
     * 自定义类型转换器
     * @param user
     * @return
     */
    @RequestMapping("/saveUser")
    public String saveUser(User user){
        System.out.println("执行了...");
        System.out.println(user);
        return "success";
    }

    /**
     * 原生的API
     * @return
     */
    @RequestMapping("/testServlet")
    public String testServlet(HttpServletRequest request, HttpServletResponse response){
        System.out.println("执行了...");
        System.out.println(request);

        HttpSession session = request.getSession();
        System.out.println(session);

        ServletContext servletContext = session.getServletContext();
        System.out.println(servletContext);

        System.out.println(response);
        return "success";
    }

}

 <%--请求参数绑定--%>
    <%--
    <a href="param/testParam?username=hehe&password=123">请求参数绑定</a>

    把数据封装Account类中
    <form action="param/saveAccount" method="post">
        姓名：<input type="text" name="username" /><br/>
        密码：<input type="text" name="password" /><br/>
        金额：<input type="text" name="money" /><br/>
        用户姓名：<input type="text" name="user.uname" /><br/>
        用户年龄：<input type="text" name="user.age" /><br/>
        <input type="submit" value="提交" />
    </form>
    --%>

    <%--把数据封装Account类中，类中存在list和map的集合
    <form action="param/saveAccount" method="post">
        姓名：<input type="text" name="username" /><br/>
        密码：<input type="text" name="password" /><br/>
        金额：<input type="text" name="money" /><br/>

        用户姓名：<input type="text" name="list[0].uname" /><br/>
        用户年龄：<input type="text" name="list[0].age" /><br/>

        用户姓名：<input type="text" name="map['one'].uname" /><br/>
        用户年龄：<input type="text" name="map['one'].age" /><br/>
        <input type="submit" value="提交" />
    </form>
    --%>

    <%--自定义类型转换器
    <form action="param/saveUser" method="post">
        用户姓名：<input type="text" name="uname" /><br/>
        用户年龄：<input type="text" name="age" /><br/>
        用户生日：<input type="text" name="date" /><br/>
        <input type="submit" value="提交" />
    </form>
    --%>


    <a href="param/testServlet">Servlet原生的API</a>

4. 常用注解

 * 常用的注解
 */
@Controller
@RequestMapping("/anno")
@SessionAttributes(value={"msg"})   // 把msg=美美存入到session域对中
public class AnnoController {

    @RequestMapping("/testRequestParam")
    public String testRequestParam(@RequestParam(name="name") String username){
        System.out.println("执行了...");
        System.out.println(username);
        return "success";
    }

    /**
     * 获取到请求体的内容
     * @return
     */
    @RequestMapping("/testRequestBody")
    public String testRequestBody(@RequestBody String body){
        System.out.println("执行了...");
        System.out.println(body);
        return "success";
    }

    /**
     * PathVariable注解
     * @return
     */
    @RequestMapping(value="/testPathVariable/{sid}")
    public String testPathVariable(@PathVariable(name="sid") String id){
        System.out.println("执行了...");
        System.out.println(id);
        return "success";
    }

    /**
     * 获取请求头的值
     * @param header
     * @return
     */
    @RequestMapping(value="/testRequestHeader")
    public String testRequestHeader(@RequestHeader(value="Accept") String header, HttpServletRequest request,HttpServletResponse response) throws IOException {
        System.out.println("执行了...");
        System.out.println(header);
        // return "success";
        // response.sendRedirect(request.getContextPath()+"/anno/testCookieValue");
        return "redirect:/param.jsp";
    }


    /**
     * 获取Cookie的值
     * @return
     */
    @RequestMapping(value="/testCookieValue")
    public String testCookieValue(@CookieValue(value="JSESSIONID") String cookieValue){
        System.out.println("执行了...");
        System.out.println(cookieValue);
        return "success";
    }

    /**
     * ModelAttribute注解
     * @return
     */
    @RequestMapping(value="/testModelAttribute")
    public String testModelAttribute(@ModelAttribute("abc") User user){
        System.out.println("testModelAttribute执行了...");
        System.out.println(user);
        return "success";
    }

    @ModelAttribute
    public void showUser(String uname, Map<String,User> map){
        System.out.println("showUser执行了...");
        // 通过用户查询数据库（模拟）
        User user = new User();
        user.setUname(uname);
        user.setAge(20);
        user.setDate(new Date());
        map.put("abc",user);
    }

    /**
     * 该方法会先执行

    @ModelAttribute
    public User showUser(String uname){
        System.out.println("showUser执行了...");
        // 通过用户查询数据库（模拟）
        User user = new User();
        user.setUname(uname);
        user.setAge(20);
        user.setDate(new Date());
        return user;
    }
     */

    /**
     * SessionAttributes的注解
     * @return
     */
    @RequestMapping(value="/testSessionAttributes")
    public String testSessionAttributes(Model model){
        System.out.println("testSessionAttributes...");
        // 底层会存储到request域对象中
        model.addAttribute("msg","美美");
        return "success";
    }

    /**
     * 获取值
     * @param modelMap
     * @return
     */
    @RequestMapping(value="/getSessionAttributes")
    public String getSessionAttributes(ModelMap modelMap){
        System.out.println("getSessionAttributes...");
        String msg = (String) modelMap.get("msg");
        System.out.println(msg);
        return "success";
    }

    /**
     * 清除
     * @param status
     * @return
     */
    @RequestMapping(value="/delSessionAttributes")
    public String delSessionAttributes(SessionStatus status){
        System.out.println("getSessionAttributes...");
        status.setComplete();
        return "success";
    }

}

6. 自定义类型转换

* 把字符串转换日期
 */
public class StringToDateConverter implements Converter<String,Date>{

    /**
     * String source    传入进来字符串
     * @param source
     * @return
     */
    public Date convert(String source) {
        // 判断
        if(source == null){
            throw new RuntimeException("请您传入数据");
        }
        DateFormat df = new SimpleDateFormat("yyyy-MM-dd");

        try {
            // 把字符串转换日期
            return df.parse(source);
        } catch (Exception e) {
            throw new RuntimeException("数据类型转换出现错误");
        }
    }

}