1.SpringMVC的数据响应方式
（1）页面跳转
- 直接返回字符串
- 通过ModelAndView对象返回
（2）回写数据
- 直接返回字符串
- 返回对象或集合
2.页面跳转
2.1 返回字符串形式
直接返回字符串：此种方式会将返回的字符串与视图解析器的前后缀拼接后跳转
为什么转发有/WEB-INF/views/，而重定向没有了
重定向代表客户端再次访问，再次请求，而WEB-INF属于一个受保护的文件夹，外界不能直接访问，要想重定向，资源必须处在一个可以有权限被访问的位置
2.2 返回ModelAndView对象
方式一：
在UserController中
index.jsp中
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>helll</title>
</head>
<body>
<p>index_success!!${username}</p>
</body>
</html>
输入请求
方式二：
方式三：
这些save方法都是最终spring帮我们调用的， 如果写的是save(Model model)这样的形参的话，springmvc调用这个方法时，会传给实际的model对象，spring内部能用；如果save(ModelAndView modelAndView)springmvc调用这个方法时，会传给实际的modelAndView对象供你使用。
方式四：
想要通过request存数据，需要request对象，通过request.setAttribute()可以往request域中存数据，在转发页面显示数据，
但是这种方式不常用
完整项目代码：
UserController.java
package com.company.controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;
@Controller
@RequestMapping("/user")
public class UserController {
@RequestMapping(value = "/quick2")
public ModelAndView save2() {
/**
* Model：模型 作用封装数据
* View：视图 作用展示数据
*/
ModelAndView modelAndView = new ModelAndView();
// 设置模型数据
modelAndView.addObject("username","root");
// 设置视图名称
modelAndView.setViewName("index");
return modelAndView;
}
// 访问quick时，帮你映射到save()方法，执行下面的逻辑，最终返回，跳到success.jsp视图中
// 请求地址，http://localhost:8080/user/quick
@RequestMapping(value = "/quick", method = RequestMethod.GET, params = {"username"})
public String save() {
System.out.println("Controller save running...");
return "success";
}
}
UserDao.java
package com.company.dao;
public interface UserDao {
void save();
}
UserDaoImpl.java
package com.company.dao.impl;
import com.company.dao.UserDao;
public class UserDaoImpl implements UserDao {
public void save() {
System.out.println("save running...");
}
}
UserService.java
package com.company.service;
public interface UserService {
void save();
}
UserServiceImpl
package com.company.service.impl;
import com.company.dao.UserDao;
import com.company.service.UserService;
public class UserServiceImpl implements UserService {
private UserDao userDao;
public void setUserDao(UserDao userDao) {
this.userDao = userDao;
}
public void save() {
userDao.save();
}
}
applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"> <!--配置userDao--> <bean id="userDao" class="com.company.dao.impl.UserDaoImpl"></bean> <!--配置userService--> <bean id="userService" class="com.company.service.impl.UserServiceImpl"> <property name="userDao" ref="userDao"></property> </bean> </beans>
spring-mvc.xml
<?xml version="1.0" encoding="UTF-8"?> <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" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd "> <!--Controller组件扫描--> <context:component-scan base-package="com.company.controller"/> <!--配置内部资源视图解析器--> <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <!--/jsp/success.jsp--> <property name="prefix" value="/"></property> <property name="suffix" value=".jsp"></property> </bean> </beans>
web.xml
<?xml version="1.0" encoding="UTF-8"?> <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"> <!--配置springmvc的前端控制器--> <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:spring-mvc.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> <!--全局初始化参数--> <context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:applicationContext.xml</param-value> </context-param> <!--配置监听器--> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <servlet> <servlet-name>UserServlet</servlet-name> <servlet-class>com.company.web.UserServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>UserServlet</servlet-name> <url-pattern>/userServlet</url-pattern> </servlet-mapping> </web-app>
index.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>helll</title>
</head>
<body>
<p>index_success!!${username}</p>
</body>
</html>