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


<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>ServletDemodisplay-name>
  <servlet>
    <servlet-name>loginservlet-name>
    <servlet-class>com.haha.LoginDemoservlet-class>
  servlet>
  <servlet-mapping>
    <servlet-name>loginservlet-name>
    <url-pattern>/wwwpppurl-pattern>
  servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.htmlwelcome-file>
    <welcome-file>index.htmwelcome-file>
    <welcome-file>index.jspwelcome-file>
    <welcome-file>default.htmlwelcome-file>
    <welcome-file>default.htmwelcome-file>
    <welcome-file>default.jspwelcome-file>
  welcome-file-list>
web-app>

创建登录界面


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

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

form>
 center>
body>
html>

创建欢迎界面


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

2.输出结果

HttpServletResponse对象实现请求重定向(四)_第1张图片

HttpServletResponse对象实现请求重定向(四)_第2张图片

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