1.1 效果图演示：java

1.2 数据准备：mysql

CREATE TABLE USER (

id INT AUTO_INCREMENT PRIMARY KEY,

NAME VARCHAR(50),

PASSWORD VARCHAR(50)

);

INSERT INTO USER (NAME, PASSWORD) VALUES('admin', '123'), ('test', '123'), ('gm', '123');

1.3 代码实现：sql

工具类

package Utils;

import java.sql.*;

import java.util.Collection;

/*

工具类

*/

public class JDBCUtils {

public static final String DIVERCLASS = "com.mysql.jdbc.Driver";

public static final String URL = "jdbc:mysql://localhost:3306/test";

public static final String USER = "root";

public static final String PASSWORD = "root";

//每次别人获取链接的时候，都须要加载该类。可是一个类只须要加载一次就够了。静态代码块只须要执行一次。

static {

try {

Class.forName(DIVERCLASS);

} catch (ClassNotFoundException e) {

e.printStackTrace();

}

}

//链接

public static Connection getConnection() {

Connection connection = null;

try {

connection = DriverManager.getConnection(URL,USER,PASSWORD);

return connection;

} catch (SQLException e) {

e.printStackTrace();

}

return connection;

}

//关闭资源

public static void close(ResultSet rs, Statement st,Connection conn){

if(rs!=null){

try {

rs.close();

} catch (SQLException e) {

e.printStackTrace();

}

}

if(st!=null){

try {

st.close();

} catch (SQLException e) {

e.printStackTrace();

}

}

if(conn!=null){

try {

conn.close();

} catch (SQLException e) {

e.printStackTrace();

}

}

}

}

package com.enjoy.test;

import Utils.JDBCUtils;

import java.sql.*;

import java.util.Scanner;

public class LoginTest {

public static void main(String[] args)throws Exception {

//建立扫描器

Scanner sc = new Scanner(System.in);

System.out.println("请输入帐号：");

String userName = sc.nextLine();

System.out.println("请输入密码：");

String password = sc.nextLine();

boolean flag = login(userName,password);

if(flag){

System.out.println("恭喜"+userName+"登陆成功");

}else {

System.out.println("帐号或密码错误或不存在");

}

}

private static boolean login(String userName, String password) throws Exception {

//获取对象

Connection connection = JDBCUtils.getConnection();

//获取SQL运输器

String sql = "select*from user where name=? and password=?";

//获得预编译对象

PreparedStatement pst = collection.prepareStatement(sql);

//给？赋值

pst.setString(1,userName);

pst.setString(2,password);

//执行SQL

ResultSet rs = pst.executeQuery();

return rs.next();

}

}