Servlet-登陆验证（含.xml文件配置）

最新推荐文章于 2021-12-25 19:35:58 发布

原创最新推荐文章于 2021-12-25 19:35:58 发布 · 273 阅读

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本文详细解析了一个基于Java Servlet的Web登录系统实现过程，包括Session管理、参数接收、登录验证及页面跳转等核心功能。

文件结构：
在这里插入图片描述
Servlet:Login.java

package dmp;

import java.io.IOException;

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

public class Login extends HttpServlet
{

	public Login(){
		super();
	}
    @Override
    protected void doGet(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		HttpSession session = request.getSession();//获取session
		Object name = session.getAttribute("user");//从session中获取用户名
		Object pwd = session.getAttribute("pwd");//从session获取用户密码
		System.out.println(name+":"+pwd); //测试一下，输出获取的用户名和密码
		session.invalidate(); //注销session
		response.sendRedirect("login.jsp"); //跳转到login.jsp页面
	}

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException
    {
    	System.err.println("***********");
    	req.setCharacterEncoding("UTF-8");
    	resp.setCharacterEncoding("UTF-8");
        String user = req.getParameter("user");
        String pwd = req.getParameter("pwd");
        if(user.equals("aaa") && pwd.equals("aaa"))
        {
        	HttpSession session = req.getSession();
            session.setAttribute("user", user);
            session.setAttribute("pwd", pwd);
            resp.sendRedirect("mainPage.jsp");
        }
        else
        {
            req.setAttribute("desc", "登陆失败!");
            req.getRequestDispatcher("index.jsp").forward(req, resp);
        }
    }

}

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!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>Insert title here</title>
</head>
<body>
<form action = "Login" method = "post">
	用户名：<input type = "text" name = "user" id = "user" ><br><br/>
	密码:<input type = "text" name = "pwd" id = "pwd"><br><br/>
	<input type = "submit" value = "登陆">
</form>
</body>
</html>

mainPage.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!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>Insert title here</title>
</head>
<body>
	<br>这是主页面<br>
</body>
</html>

.xml文件

<?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>yanzheng</display-name>
  <welcome-file-list>
    <welcome-file>Login.jsp</welcome-file>
    <welcome-file>Login.jsp</welcome-file>
    <welcome-file>Login.jsp</welcome-file>
  </welcome-file-list>
  <servlet>
		<servlet-name>Login</servlet-name>
		<servlet-class>dmp.Login</servlet-class>
	</servlet>
	<servlet-mapping>
		<servlet-name>Login</servlet-name>
		<url-pattern>/Login</url-pattern>
	</servlet-mapping>
</web-app>