JAVA web实现用户注册与注销

先创建dao package 下的UserDao类 model下的UserService类，sevlet下的AddServlet、HelloServlet、LoginServlet类,util下的DButil类。

在web下导入两个jar包并创建add.jsp、delete.jsp,index.jsp
实体类User属性设置

package com.zr0629.model;

public class User {
    private int id;
    private String name;
    private String password;
    private String age;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getAge() {
        return age;
    }

    public void setAge(String age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", password='" + password + '\'' +
                ", age='" + age + '\'' +
                '}';
    }
}

数据库连接

package com.zr0629.util;

import java.sql.*;

public class DButil {
    public static Connection getConnection() throws SQLException, ClassNotFoundException {
        Class.forName("com.mysql.jdbc.Driver");
        System.out.println("连接数据库");
        //创建链接
        Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/testtt?useSSL=false","root","123456");
        return connection;
    }
    public static void closeAll(ResultSet rs, Statement stmt,Connection conn) throws SQLException{
        if(rs!=null){
            rs.close();
        }
        if(stmt!=null){
            stmt.close();
        }
        if(conn!=null){
            conn.close();
        }
    }
}

UserDao类

package com.zr0629.dao;

import com.zr0629.model.User;
import com.zr0629.util.DButil;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;

public class UserDao {
    public int add(User user) {
        Connection connection=null;
        PreparedStatement pstmt = null;
        int count=0;
        try{
            connection = DButil.getConnection();
            //获得执行sql的Statement对象
            pstmt = connection.prepareStatement("insert into a(name,password,age) values (?,?,?)");
            pstmt.setString(1,user.getName());
            pstmt.setString(2,user.getPassword());
            pstmt.setString(3,user.getAge());
            //执行sql，获得结果
            count=pstmt.executeUpdate();
            System.out.println("insert操作："+count);
            return count;
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            try {
                DButil.closeAll(null,pstmt,connection);
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        return count;
    }

    public int del(User user) {
        Connection connection=null;
        PreparedStatement pstmt = null;
        int count=0;
        try{
            connection = DButil.getConnection();
            //获得执行sql的Statement对象
            pstmt = connection.prepareStatement("DELETE FROM `a` WHERE name=? AND password=? AND age = ?");
            pstmt.setString(1,user.getName());
            pstmt.setString(2,user.getPassword());
            pstmt.setString(3,user.getAge());
            //执行sql，获得结果
            count=pstmt.executeUpdate();
            System.out.println("delete操作："+count);
            return count;
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            try {
                DButil.closeAll(null,pstmt,connection);
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        return count;
    }
}

UserService类

package com.zr0629.service;

import com.zr0629.dao.UserDao;
import com.zr0629.model.User;

import java.sql.SQLException;

public class UserService {
    UserDao userDao=new UserDao();
    public int add(User user) {
        System.out.println("service中add方法被调用");
        return userDao.add(user);
    }

    public int del(User user) {
        System.out.println("service中del方法被调用");
        return userDao.del(user);
    }
}

AddServlet类

package com.zr0629.servlet;

import com.zr0629.model.User;
import com.zr0629.service.UserService;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.sql.SQLException;

public class AddServlet extends HttpServlet {
    UserService userService=new UserService();
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
       System.out.println("执行了doPost");
       String method = req.getParameter("method");
       if(method.equals("save")){
           insert(req, resp);
       } else if(method.equals("delete")){
                delete(req,resp);
       }


       }


    public void insert(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        User user=new User();
        String name=req.getParameter("name");
        String password=req.getParameter("password");
        String age=req.getParameter("age");

        user.setName(name);
        user.setPassword(password);
        user.setAge(age);
        System.out.println(user);

        int count= userService.add(user);
        if(count>0){
            resp.sendRedirect("/index.jsp");
        }else{
            resp.getWriter().write("failed");
        }

    }

    public void delete(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        User user=new User();
        String name=req.getParameter("name");
        String password=req.getParameter("password");
        String age=req.getParameter("age");

        user.setName(name);
        user.setPassword(password);
        user.setAge(age);
        System.out.println(user);

        int count= userService.del(user);
        if(count>0){
            resp.sendRedirect("/index.jsp");
        }else{
            resp.getWriter().write("failed");
        }

    }

}

登录index.jsp

  <head>
    <title>$Title$</title>
  </head>
  <body>
  <h1>登陆页面</h1>
  <form action="/login" method="post">
    name:<input name="name" type="text">
    password:<input name="password" type="password">
    <input type="submit" value="login">
  </form>
  <a href="add.jsp">跳转到注册页面</a>
  <a href="delete.jsp">跳转到删除页面</a>
  </body>
</html>

注册add.jsp

<head>
    <title>注册</title>
</head>
<body>
<h1>注册页面</h1>
<form action="/add?method=save"method="post">
    name:<input name="name"type="text">
    password:<input name="password"type="password">
    age:<input name="age"type="text">
    <input type="submit" value="注册">
</form>
</body>
</html>

删除（注销）delete.jsp

<html>
<head>
    <title>删除</title>
</head>
<body>
<h1>删除页面</h1>
<form action="/add?method=delete"method="post">
    name:<input name="name"type="text">
    password:<input name="password"type="password">
    age:<input name="age"type="text">
    <input type="submit" value="删除">
</form>
</body>
</html>