IDEA使用JDBC连接MYSQL库

import java.sql.*;

public class mysqltestdemo {
    public static void main(String[] args) throws Exception {
//     JDBC的使用
//        1.通过反射加在 加载驱动
         Class.forName("com.mysql.jdbc.Driver");
//        2.建立连接
        Connection connection = DriverManager.getConnection("jdbc:mysql://master:3306/shujia", 
                                                            "root", "123456");
//        3.创建执行器,用来执行SQL语句
//          1.createStatement()
//            2.prepareStatement()
        Statement statement = connection.createStatement();
        String sql ="select * from student";
//        4.执行SQL语句
        ResultSet rs = statement.executeQuery(sql);
//        5.获取结果
        System.out.println(rs);
//        6.关闭
        rs.close();
        statement.close();
        connection.close();
    }

import java.sql.*;

public class mysqltestdemo {
    public static void main(String[] args) throws Exception {
//     JDBC的使用
//        1.通过反射加在 加载驱动
        Class.forName("com.mysql.jdbc.Driver");
//        2.建立连接
        Connection connection = DriverManager.getConnection("jdbc:mysql://master:3306/shujia",
                "root", "123456");
//        3.创建执行器,用来执行SQL语句
//          1.createStatement()
//            2.prepareStatement()
        Statement statement = connection.createStatement();
        String sql ="select * from student";
//        4.执行SQL语句
        ResultSet rs = statement.executeQuery(sql);
//        5.获取结果
        while(rs.next()){
            System.out.println(rs.getInt("id"));
            System.out.println(rs.getString("name"));
            System.out.println(rs.getInt("sex"));
            System.out.println(rs.getString("age"));
        }
//        6.关闭
        rs.close();
        statement.close();
        connection.close();
    }
}

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
import java.util.Scanner;

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

        Scanner scanner = new Scanner(System.in);
        String name = scanner.next();
        int age=scanner.nextInt();
        String sex=scanner.next();

        Class.forName("com.mysql.jdbc.Driver");
        Connection connection = DriverManager.getConnection("jdbc:mysql://master:3306/shujia",
                "root", "123456");
        Statement statement = connection.createStatement();

        String sql="insert into student(name,age,sex) values(\""+name+"\","+age+",\""+sex+"\")";
        int i = statement.executeUpdate(sql);
        System.out.println(i);
        if(i==1){
            System.out.println("注册成功");
        }else{
            System.out.println("注册失败");
        }
        statement.close();
        connection.close();
    }
}

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;

public class mysqlDelete {
    public static void main(String[] args) throws Exception {
        Class.forName("com.mysql.jdbc.Driver");
        Connection connection = DriverManager.getConnection("jdbc:mysql://master:3306/shujia",
                "root", "123456");
        Statement statement = connection.createStatement();
        String sql="delete from student where name=‘zhontg‘";
        int i = statement.executeUpdate(sql);
        System.out.println(i);
        statement.close();
        connection.close();
    }
}

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;

public class mysqlDelete {
    public static void main(String[] args) throws Exception {
        Class.forName("com.mysql.jdbc.Driver");
        Connection connection = DriverManager.getConnection("jdbc:mysql://master:3306/shujia",
                "root", "123456");
        Statement statement = connection.createStatement();
        String sql="delete from student where name=‘zhontg‘";
        int i = statement.executeUpdate(sql);
        System.out.println(i);
        statement.close();
        connection.close();
    }
}

package mysql.statement;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Scanner;

public class Login01 {
    public static void main(String[] args) throws  Exception {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入用户：");
        String username = scanner.next();
        System.out.println("请输入密码：");
        String password = scanner.next();

        Class.forName("com.mysql.jdbc.Driver");
        Connection connection = DriverManager.getConnection("jdbc:mysql://master:3306/shujia",
                "root", "123456");
        Statement statement = connection.createStatement();
//      1.通过username去mysql中查找有没有这一条记录(存在：输入密码，不存在：报错)
//      2.存在之后，用查到的密码匹配输入的密码
        String sql="select * from user where username=‘"+username+"‘";
        ResultSet rs = statement.executeQuery(sql);
        if(!rs.next()){
            System.out.println("用户输出错误");
//            结束
        }
//        匹配密码
        String password1 = rs.getString("password");
        if(password==null || !password.equals(password1)){
            System.out.println("密码不匹配失败");
        }else {
            System.out.println("登陆成功");
        }
        rs.close();
        statement.close();
        connection.close();
    }
}

package mysql.statement;

import java.sql.*;
import java.util.Scanner;

public class Login02 {
    public static void main(String[] args) throws  Exception {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入用户：");
        String username = scanner.nextLine();
        System.out.println("请输入密码：");
        String password = scanner.next();

        Class.forName("com.mysql.jdbc.Driver");
        Connection connection = DriverManager.getConnection("jdbc:mysql://master:3306/shujia",
                "root", "123456");
        String sql="select * from user where username=?";
        PreparedStatement statement = connection.prepareStatement(sql);
        statement.setString(1,username);
//      1.通过username去mysql中查找有没有这一条记录(存在：输入密码，不存在：报错)
//      2.存在之后，用查到的密码匹配输入的密码
        ResultSet rs = statement.executeQuery();
        if(!rs.next()){
            System.out.println("用户输出错误");
//            结束
        }
//        匹配密码
        String password1 = rs.getString("password");
        if(password==null || !password.equals(password1)){
            System.out.println("密码不匹配失败");
        }else {
            System.out.println("登陆成功");
        }
        rs.close();
        statement.close();
        connection.close();
    }
}