HttpServletResponse对象实现请求重定向(四)

(一)请求重定向的概念

1.重定向是指当浏览器向Tomcat服务器发送请求时，由于一个Servlet1类无法完成所有请求响应工作，这时候Servlet1类会通知浏览器重新定向到另一个Servlet2类。浏览器再次发送请求Servlet2,来获得Servlet2的响应。

(二)使用HttpServletResponse对象实现请求重定向

1.代码演示

创建servlet实例

package com.haha;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/LoginDemo")
public class LoginDemo extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        response.setContentType("text/html;charset=utf-8");
        String username=request.getParameter("username");
        String password=request.getParameter("password");
         if(("123").equals(username)&&("123").equals(password)){
            response.sendRedirect("/ServletDemo/Welcome.html");
        }else{

            response.sendRedirect("/ServletDemo/login.html");
        }

    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        doGet(request, response);
    }

}

配置Servlet对象

<?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" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>ServletDemo</display-name>
  <servlet>
    <servlet-name>login</servlet-name>
    <servlet-class>com.haha.LoginDemo</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>login</servlet-name>
    <url-pattern>/wwwppp</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
</web-app>

创建登录界面

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<center> 
<form action="/ServletDemo/LoginDemo" method="get">

   用户名：<input  type="text" name="username" /><br><br> 
   密&nbsp;&nbsp;&nbsp;&nbsp;码：<input  type="password" name="password"/><br><br><br>
   <input type="submit"  value="登录"> 
  &nbsp;&nbsp;&nbsp; <input type="reset"  value="重置">

</form>
 </center>
</body>
</html>

创建欢迎界面

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
欢迎来到魔鬼训练营
</body>
</html>

2.输出结果

这里写图片描述

HttpServletResponse对象实现请求重定向(四)

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