servlet之登录页面

来源：互联网发布：java 圆周率计算公式编辑：程序博客网时间：2024/05/21 11:07

<span style="font-size:18px;">首先建一个名为 LoginServlet的servlet：import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class LoginServlet extends HttpServlet {private static final long serialVersionUID = 1L;public LoginServlet() {super();}public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {this.doPost(request, response);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {String username=request.getParameter("uname");String password=request.getParameter("upwd");System.out.println("用户名 ==》"+username);System.out.println("密码 ==》"+password);}}然后在index.jsp中加入表单：<pre name="code" class="html"><%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <title>登录页面</title>  </head>    <body><form action="<%= request.getContextPath() %>/LoginServlet" method="post">userName:<input type="text" name="uname" /><br />password:<input type="password" name="upwd" /><br /><input type="submit" value="Login" /><input type="submit" value="Reset" /></form>  </body></html>

最后在web.xml中配置路径：

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

只要在浏览器中访问路径http://127.0.0.1:8080/Login2/index.jsp就可以了,不过这只是响应了登录的请求，没有登录的效果，经过优化后可以实现用户名和密码的匹配登录和登录跳转的页面：

优化后的LoginServlet为：

package com.jikexueyuan.LoginServlet;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.RequestDispatcher;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class LoginServlet extends HttpServlet {private static final long serialVersionUID = 1L;public LoginServlet() {super();}public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {this.doPost(request, response);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {String username=request.getParameter("uname");String password=request.getParameter("upwd");System.out.println("用户名 ==》"+username);System.out.println("密码 ==》"+password);String forward=null;//跳转页面：if(username.equals("panpan")&&password.equals("963524")){//请求转发//forward="/success.jsp";forward="http://www.jikexueyuan.com";//RequestDispatcher rd=request.getRequestDispatcher(forward);//rd.forward(request, response);//请求重定向response.sendRedirect(forward);}else{//请求转发//forward="/false.jsp";//RequestDispatcher rd=request.getRequestDispatcher(forward);//rd.forward(request, response);//请求重定向response.sendRedirect(request.getContextPath()+"/false.jsp");}}}添加一个登录成功的界面success.jsp:<pre name="code" class="html"><%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">        <title>登录成功</title>      </head>    <body>   登录成功，啦啦啦啦 <br> 你提交的信息为：<br> 用户名：<%=request.getParameter("uname") %><br> 密码：    <%=request.getParameter("upwd") %><br> <a href="index.jsp">返回登录页面</a>     </body></html>

再添加一个登录失败的页面false.jsp:

<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">        <title>登录失败</title>      </head>    <body>    抱歉，您的页面登录失败！ <br>    请检查您的信息：<br>    用户名：<%=request.getParameter("uname") %><br>    密码：    <%=request.getParameter("upwd") %><br> <a href="index.jsp">返回登录页面</a>  </body></html>

登录效果：

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