简单的纯java语言登录和注册功能

本系统是由纯java代码编写的登录和注册功能
工具有：eclipse,mysql
用到的mysql加载驱动在此免费下载：http://download.csdn.net/detail/su1573/9884583
下面是代码部分

**Main.java**package com.su.main;public class Main {    public static void main(String[] args) {        // TODO Auto-generated method stub            new Menu();    }}

**Menu.java**package com.su.main;import java.util.Scanner;public class Menu {    Operate operate = new Operate();    public Menu(){        while (true){            this.show();        }    }    public void show(){        System.out.println("欢迎进入阿辉信息管理系统");        System.out.println("***1-登录***");        System.out.println("***2-注册***");        System.out.println("***0-系统退出***");        Scanner input = new Scanner(System.in);        System.out.println("请选择：");        int i = input.nextInt();        switch(i){            case 1 : {                operate.login();                break;            }            case 2 : {                operate.register();                break;            }            case 0 : {                System.exit(1);                break;            }            default: {                System.out.println("请选择正确的操作！");            }        }    }}

**Operate.java**package com.su.main;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.util.Scanner;public class Operate {    private Connection conn = null;    private PreparedStatement ps = null;    private ResultSet rs = null;    public  void login(){        Scanner scan = new Scanner(System.in);        int i = 3;        String username = null;        String password = null;        while(i != -1){              //循环进行                System.out.print("请输入总系统用户名：");            username = scan.next();         //输入用户名            while(username == null){    //判断用户名是否为空                System.out.print("请输入总系统用户名：");                username = scan.next();            }            System.out.println("请输入总系统密码：");            password = scan.next();        //输入密码            while(password == null){      //判断密码是否为空                System.out.println("请输入总系统密码：");                password = scan.next();               }//          String str1 = "su";         //定义初始用户名//          String str2 = "su";//              //定义初始密码            if(checkUserLogin(username,password)){    //比较输入的用户名、密码是否和初始值相同                System.out.println("欢迎"+username+",您已成功登录");                new Menu();            }            else{                if(i == 0){      //三次登陆都错，退出系统                    System.out.println("对不起，您三次都输入错误，系统将退出！！！");                    System.exit(1);                }                System.out.println("对不起您输入的用户名或密码有误，请重新输入（"+ i-- +"次机会）！！！");            }        }        scan.close();      }    public  void register(){        User user = new User();        Scanner input = new Scanner(System.in);        System.out.println("请输入您的姓名：");        String username = input.next();        user.setUsername(username);        System.out.println("请输入您的密码：");        String userpassword = input.next();        user.setUserpassword(userpassword);        try {            if(doAdd(user)){                System.out.println("注册成功！");            }else{                System.out.println("注册失败！");            }        } catch (Exception e) {            e.printStackTrace();        }    }    public  boolean checkUserLogin(String userName,String userPwd){        boolean flag = false;        User user = null;        try{            conn = DBConn.createDBConn();            String sql = "select * from user where username=? and userpassword=?";            ps = conn.prepareStatement(sql);            ps.setString(1, userName);            ps.setString(2, userPwd);            rs = ps.executeQuery();            while(rs.next()){                user = new User();                user.setUsername(rs.getString("username"));                user.setUserpassword(rs.getString("userpassword"));            }            flag = true;        }catch(Exception ex){            ex.printStackTrace();        }finally{            DBConn.closeConn(conn);        }        return flag;    }    public boolean doAdd(User user) throws Exception{        boolean flag = false;        PreparedStatement pstmt = null;        String sql = "INSERT INTO user(username,userpassword)" + "VALUES(?,?)";        try{            conn = DBConn.createDBConn();            pstmt = conn.prepareStatement(sql);            pstmt.setString(1, user.getUsername());             pstmt.setString(2, user.getUserpassword());            if (pstmt.executeUpdate() > 0) {                flag = true;            }        } catch (Exception e) {            throw e;        } finally {             if (pstmt != null) {                try {                    pstmt.close();                } catch (Exception e1) {                }            }        }        return flag;    }}

**DBConn,java**package com.su.main;import java.sql.Connection;import java.sql.DriverManager;import java.sql.Statement;public class DBConn {//  public static void main(String[] args)throws Exception {//      createDBConn();//      //      System.out.println("成功");//      Statement state = createDBConn().createStatement();//      System.out.println(state);//  }    public static Connection createDBConn(){        //得到数据连接        try{            Class.forName("com.mysql.jdbc.Driver");            Connection conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/userdb","root","su1573");            return conn;        }catch(Exception e){            e.printStackTrace();            return null;        }    }    public static void closeConn(Connection conn){            try{                conn.close();            }catch(Exception e){                e.printStackTrace();            }        }}

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运行结果如图：

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数据库数据如图：