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JavaWeb_利用Servlet处理注册登录请求

利用Servlet处理注册登录请求

　　程序结构

<%@page import="com.Gary.model.User"%>
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Insert title here</title>
</head>
<body>

<%
Object o = session.getAttribute("user");
if(o!=null){
    User user = (User)o;
    out.println("当前登录用户："+user.getUsername()+"<br/>");
}
%>

<%
Object o2 = application.getAttribute("userNumber");
if(o2!=null){
    out.println("当前登录用户"+o2+"个<br/>");
}
%>

<a href="login.jsp">登录</a>
<a href="register.jsp">注册</a>

</body>
</html>

index.jsp

<%@page import="com.Gary.model.User"%>
<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Insert title here</title>
</head>
<body>
<%
Object o = session.getAttribute("user");
if(o!=null){
    User user = (User)o;
    out.println("当前登录用户："+user.getUsername()+"<br/>");
}
%>

<%
Object msg = request.getAttribute("message");
if(msg!=null)
    out.println(msg);
%>

登录<hr>
<form action="login_do" method="post">
用户名：<input type="text" name="username" /><br/>
密码：<input type="password" name="password" /><br/>
<input type="submit" value="登录" />
</form>
</body>
</html>

<%@ page import="com.Gary.model.User" %>
<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Insert title here</title>
</head>
<body>
<%
//通过session的getAttribute进行访问
User user = (User)session.getAttribute("user");
%>

用户名：<%=user.getUsername()%><br/>
年龄：<%=user.getAge()%><br/>
性别：<%=user.getSex()%><br/>
</body>
</html>

personCenter.jsp

<%@page import="com.Gary.model.User"%>
<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Insert title here</title>
</head>
<body>
<%
Object o = session.getAttribute("user");
if(o!=null){
    User user = (User)o;
    out.println("当前登录用户："+user.getUsername()+"<br/>");
}
%>

<%
Object msg = request.getAttribute("message");
if(msg!=null)
    out.println(msg);
%>

<form action="register_do" method="post">
用户名：<input type="text" name="username" /><br/>
密码：<input type="password" name="password" /><br/>
年龄：<input type="text" name="age" /><br/>
性别： 男<input type="radio" name="sex" value="男" />女<input type="radio" name="sex" value="女" /><br/>
<input type="submit" value="注册" />
</form>

</body>
</html>

package com.Gary.model;

public class User {
    private String username;
    private String password;
    private int age;
    private String sex;
    public User(String username, String password, int age, String sex) {
        super();
        this.username = username;
        this.password = password;
        this.age = age;
        this.sex = sex;
    }
    
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    
    
    
}

User.java

package com.Gary.servlet;

import java.io.IOException;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.Gary.model.User;
import com.Gary.util.DBUtil;


@WebServlet("/login_do")
public class LoginServlet extends HttpServlet {
   
    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String username = request.getParameter("username");
        String password = request.getParameter("password");

        User user = DBUtil.verifyAccount(username,password);
        if(user==null){
//            out.println("登录失败，用户名或密码错误");
            request.setAttribute("message","登录失败，用户名或密码错误");
            request.getRequestDispatcher("login.jsp").forward(request,response);
        }else{
//            out.println("登录成功");
            int number = 0;
            //获取到application对象
            ServletContext application = this.getServletContext();
            //第一次登录用户时if不瞒住,number=0
            if(application.getAttribute("userNumber")!=null){
                number = (Integer)application.getAttribute("userNumber");
            }
            
            //登录过一个用户后在原基础number上进行++
            number++;

            application.setAttribute("userNumber",number);
            
            //通过seesion的setAttribute传递数据
            request.getSession().setAttribute("user", user);
            //登录请求的转发,将数据传递给personCenter.jsp页面
            request.getRequestDispatcher("personCenter.jsp").forward(request,response);
        }
    }

}

LoginServlet.java

package com.Gary.servlet;

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;

import com.Gary.util.DBUtil;


@WebServlet("/register_do")
public class RegisterServlet extends HttpServlet {

    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        int age = Integer.parseInt(request.getParameter("age"));
        String sex = request.getParameter("sex");

        boolean isSuccess = DBUtil.addUser(username,password,age,sex);

        //使用请求转发
        if(isSuccess){
            request.setAttribute("message", "注册成功，请登录");
            //通过getRequestDispatcher传递路径将请求转发给login.jsp
            request.getRequestDispatcher("login.jsp").forward(request,response);
        }else{
            request.setAttribute("message", "注册失败，用户名重复");
            //通过getRequestDispatcher传递路径将请求转发给login.jsp
            request.getRequestDispatcher("register.jsp").forward(request,response);
        }
        
    }

}

RegisterServlet.java

package com.Gary.util;

import java.util.HashMap;
import java.util.Map;

import com.Gary.model.User;


public class DBUtil {
    
    private static Map<String ,User>db = new HashMap<String,User>();
    
    public static boolean addUser(String username,String password,int age,String sex) {
        //TODO
        
        if(db.containsKey(username)) {
            return false;
        }else {
            User user=new User(username,password,age,sex);
            db.put(username, user);
            return true;
        }
    }
    
    //账号校验
    public static User verifyAccount(String username,String password) {
        if(db.containsKey(username)) {
            User user = db.get(username);
            if(user.getPassword().equals(password)) {
                return user;
            }else {
                return null;
            }
        }
        return null;
    }
}

DBUtil.java

　　通过RegisterServlet.java和LoginServlet.java来处理注册登录请求

用户注册

　　通过户数据模型驱动User,java和DBUtild.java中对数据进行本地处理

　　登录同理注册

<form action="register_do" method="post">
用户名：<input type="text" name="username" /><br/>
密码：<input type="password" name="password" /><br/>
年龄：<input type="text" name="age" /><br/>
性别： 男<input type="radio" name="sex" value="男" />女<input type="radio" name="sex" value="女" /><br/>
<input type="submit" value="注册" />
</form>

　　RegisterServlet.java通过doPost()方法处理注册信息

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        int age = Integer.parseInt(request.getParameter("age"));
        String sex = request.getParameter("sex");

        boolean isSuccess = DBUtil.addUser(username,password,age,sex);

        //使用请求转发
        if(isSuccess){
            request.setAttribute("message", "注册成功，请登录");
            //通过getRequestDispatcher传递路径将请求转发给login.jsp
            request.getRequestDispatcher("login.jsp").forward(request,response);
        }else{
            request.setAttribute("message", "注册失败，用户名重复");
            //通过getRequestDispatcher传递路径将请求转发给login.jsp
            request.getRequestDispatcher("register.jsp").forward(request,response);
        }
        
    }

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原文地址：https://www.cnblogs.com/1138720556Gary/p/10296096.html