对于某些Controller的处理方法，当返回值为String类型时，返回的结果中可能含有forward或redirect前缀；
如：
Usercontroller代码
- @Controller
- @RequestMapping("/user")
- public class UserController {
- @RequestMapping("/forward")
- public String replyWithForward(HttpServletRequest request, String userId){
- request.setAttribute("userid", userId);
- System.out.println("userId =" +userId);
- return "forward:hello";
- }
- @RequestMapping("/redirect")
- public String replyWithRedirect(HttpServletRequest request, String userId){
- request.setAttribute("userid", userId);
- System.out.println("userId = "+userId);
- return "redirect:hello";
- }
- }
测试页面hello.jsp;
Html代码
- <%@ page language="java" contentType="text/html; charset=UTF-8"
- pageEncoding="UTF-8"%>
- <%
- String userId = (String)request.getAttribute("userid");
- System.out.println("获取到的userId为："+userId);
- %>
- <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
- <html>
- <head>
- <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
- <title>测试页面</title>
- </head>
- <body>
- hello, <%= userId %>;
- </body>
- </html>
当路径为 http://localhost:8080/crazysnailweb/user/forward?userId=123时，浏览器中的URL不会发生变化，且页面输出：
当路径为http://localhost:8080/crazysnailweb/user/redirect?userId=123 时，浏览器中URL变为http://localhost:8080/crazysnailweb/user/hello，且页面输出：
注：redirect会让浏览器发起一个新的请求，因而原来request对象中的参数丢失；而forward所到的目标地址位于当前请求中，request中的参数不会丢失；
参考：http://blog.youkuaiyun.com/jackpk/article/details/19121777
http://dufengx201406163237.iteye.com/blog/2097416
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