servlet重定向和转发的区别_session跨页面传值

为了说明JSP中Forward和Redirect之间的区别，写了一个测试web工程

index.jsp：

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1">
<title>index</title>
</head>
<body>
<form action='search' method='post'>
	Key Word<input id='keyWord' name='keyWord' value=''/>
	<input type="submit" value='Search'/>
</form>
</body>
</html>

result.jsp：

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1">
<title>result</title>
</head>
<body>
	Key Word:<%= request.getParameter("keyWord")%><br/>
	The key Word can not be null or have * within it.
</body>
</html>

web.xml：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
		xmlns="http://java.sun.com/xml/ns/javaee" 
		xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" 
		xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
				http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" 
		id="WebApp_ID" version="2.5">
  <display-name>JSP</display-name>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  
  <servlet>
	  <servlet-name>test</servlet-name>
	  <servlet-class>com.sean.test</servlet-class>
  </servlet>
  <servlet-mapping>
  		<servlet-name>test</servlet-name>
  		<url-pattern>/search/*</url-pattern>
  </servlet-mapping>
</web-app>

test.java：

package com.sean;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class test extends HttpServlet {
	private static final long serialVersionUID = 1L;
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		String keyWord = req.getParameter("keyWord");
		if(keyWord == null || keyWord.equals("") || keyWord.contains("*")){
			req.getRequestDispatcher("result.jsp").forward(req, resp);
		}else{
			//use baidu to search the keyword
			resp.sendRedirect("http://www.baidu.com/s?wd=" + keyWord);
		}
	}     
}

一，Forward

访问测试web工程主页，并在输入框中输入*