JavaEE（14）SpringMVC中结果跳转方式、数据处理、乱码问题
1. 结果跳转
1. SpringMVC实现转发和重定向（不需要视图解析器）
（1）配置web.xml
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<servlet>
<servlet-name>springmvcservlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class>
<init-param>
<param-name>contextConfigLocationparam-name>
<param-value>classpath:springmvc-servlet.xmlparam-value>
init-param>
<load-on-startup>1load-on-startup>
servlet>
<servlet-mapping>
<servlet-name>springmvcservlet-name>
<url-pattern>/url-pattern>
servlet-mapping>
web-app>
（2）配置springmvc-servlet.xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<context:component-scan base-package="com.nelws.controller"/>
<mvc:default-servlet-handler/>
<mvc:annotation-driven/>
beans>
（3）编写Controller
@Controller
public class ControllerTest {
@RequestMapping("/ct/t01")
public String test01(Model model){
model.addAttribute("msg","ControllerTest");
//转发
return "/WEB-INF/jsp/test.jsp";
}
@RequestMapping("/ct/t02")
public String test02(){
//转发
return "forward:/index.jsp";
}
@RequestMapping("/ct/t03")
public String test03(){
//重定向
return "redirect:/index.jsp";
}
}
（4）编写视图界面
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Titletitle>
head>
<body>
${msg}
body>
html>
（5）测试
2. SpringMVC实现转发和重定向（需要视图解析器）
（1）配置web.xml
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<servlet>
<servlet-name>springmvcservlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class>
<init-param>
<param-name>contextConfigLocationparam-name>
<param-value>classpath:springmvc-servlet.xmlparam-value>
init-param>
<load-on-startup>1load-on-startup>
servlet>
<servlet-mapping>
<servlet-name>springmvcservlet-name>
<url-pattern>/url-pattern>
servlet-mapping>
web-app>
（2）配置springmvc-servlet.xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<context:component-scan base-package="com.nelws.controller"/>
<mvc:default-servlet-handler/>
<mvc:annotation-driven/>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/"/>
<property name="suffix" value=".jsp"/>
bean>
beans>
（3）编写Controller
@Controller
public class ControllerTest2 {
@RequestMapping("/ct2/t01")
public String test01(Model model){
model.addAttribute("msg","ControllerTest2");
//转发
return "test";
}
@RequestMapping("/ct2/t02")
public String test02(){
//转发
return "forward:/index.jsp";
}
@RequestMapping("/ct2/t03")
public String test03(){
//重定向
return "redirect:/index.jsp";
}
}
（4）编写视图界面
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Titletitle>
head>
<body>
${msg}
body>
html>
（5）测试
2. 数据处理
1. 提交数据处理
（1）提交的域名城和处理方法的参数名称一致：localhost:8080/dc/t01?name=laowang
@RequestMapping("/dc/t01")
public String test01(String name){
System.out.println(name); //laowang
return "test";
}
（2）提交的域名城和处理方法的参数名称不一致：localhost:8080/dc/t02?username=xiaoli
@RequestMapping("/dc/t02")
public String test02(@RequestParam("username") String name){
System.out.println(name); //xiaoli
return "test";
}
（3）提交的是一个对象：localhost:8080/dc/t03?id=1&name=haha&age=13
使用对象的话，前端传递的参数名和对象名必须一致，否则就是null
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
private int id;
private String name;
private int age;
}
@RequestMapping("/dc/t03")
public String test03(User user){
System.out.println(user); //User(id=1, name=haha, age=13)
return "test";
}
2. 显示数据到前端
（1）通过ModelAndView（和以前一样 不做过多解释）
public class ControllerTest1 implements Controller {
public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
//返回一个模型视图对象
ModelAndView mv = new ModelAndView();
mv.addObject("msg","ControllerTest1");
mv.setViewName("test");
return mv;
}
}
（2）通过ModelMap：http://localhost:8080/sc/t01?name=laowang
@RequestMapping("/sc/t01")
public String test01(String name, ModelMap map){
map.addAttribute("msg",name);
System.out.println(name); //laowang
return "test";
}
（3）通过Model：http://localhost:8080/sc/t02?name=xiaoli
@RequestMapping("/sc/t02")
public String test01(String name, Model model){
model.addAttribute("msg",name);
System.out.println(name); //xiaoli
return "test";
}
（4）对比
Model只有寥寥几个方法只适合用于储存数据，简化了新手对于Model对象的操作和理解
ModelMap继承了 LinkedMap，除了实现了自身的一些方法，同样的继承LinkedMap的方法和特性
ModelAndView可以在储存数据的同时，可以进行设置返回的逻辑视图，进行控制展示层的跳转
3. 中文乱码问题
1. 解决办法：使用SpringMVC自带的过滤器，在web.xml中配置
<filter>
<filter-name>encodingfilter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilterfilter-class>
<init-param>
<param-name>encodingparam-name>
<param-value>utf-8param-value>
init-param>
filter>
<filter-mapping>
<filter-name>encodingfilter-name>
<url-pattern>/*url-pattern>
filter-mapping>