Java连接Mysql实现增删改查_java连接mysql数据库删除数据

Java连接Mysql实现增删改查

JDBC通用步骤

1.加载驱动
2.创建连接
3.写sql语句
4.获得statement语句
5.执行sql得到结果集
6.处理结果集
7.关闭资源

Mysql表格

（1）DBUtil(1.加载驱动2.创建连接)

package com.zr.util;

import java.sql.*;

public class DBUtil {
public static Connection getConnection() throws ClassNotFoundException, SQLException {
//1.加载驱动
Class.forName(“com.mysql.jdbc.Driver”);
//2.创建连接
Connection connection= DriverManager.getConnection(“jdbc:mysql://localhost:3306/wzsxy”,“root”,“123456”);
return connection;
}

public static void closeAll(ResultSet resultSet, Statement statement,Connection connection) throws SQLException {
    if(resultSet!=null){
        resultSet.close();
    }
    if(statement!=null){
        statement.close();
    }
    if(connection!=null){
        connection.close();
    }
}
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}

（2）增加数据

package com.zr;

import com.zr.util.DBUtil;

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

public class Add {
	public static void main(String[] args) throws ClassNotFoundException, SQLException {
   		Connection connection= DBUtil.getConnection();
    	//3.写sql语句
    	String sql="insert into tb_user (username,password) value('creamd','123')";
    	//4.获得statement对象
    	PreparedStatement statement=connection.prepareStatement(sql);
    	//5.执行sql 得到结果集
    	statement.executeUpdate();
    	//6.处理结果集
    	//7.关闭资源
    	DBUtil.closeAll(null,statement,connection);

	}
}
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（3）删除数据

package com.zr;

import com.zr.util.DBUtil;

import java.sql.*;

public class Delete {
    public static void main(String[] args) throws ClassNotFoundException, SQLException {
        Connection connection=DBUtil.getConnection();
        //3.写sql语句
        String sql="delete from tb_user where id=7";
        //4.获得statement对象
        PreparedStatement statement=connection.prepareStatement(sql);
        //5.执行sql 得到结果集
        statement.executeUpdate();
        //6.处理结果集
        //7.关闭资源
        DBUtil.closeAll(null,statement,connection);
    }
}
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（4）更改数据

package com.zr;

import com.zr.util.DBUtil;

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

public class update {
    public static void main(String[] args) throws ClassNotFoundException, SQLException {
        Connection connection= DBUtil.getConnection();
        //3.写sql语句
        String sql="update tb_user set username='Pg one' where username='Cyj'";
        //4.获得statement对象
        PreparedStatement statement=connection.prepareStatement(sql);
        //5.执行sql 得到结果集
        statement.executeUpdate();
        //6.处理结果集
        //7.关闭资源
        DBUtil.closeAll(null,statement,connection);
    }
}
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（5）查找数据

package com.zr;

import com.zr.util.DBUtil;

import java.sql.*;

public class Find {
    public static void main(String[] args) throws ClassNotFoundException, SQLException {
        Connection connection=DBUtil.getConnection();
        //3.写sql语句
        String sql="select * from tb_user";
        //4.获得statement对象
        PreparedStatement statement=connection.prepareStatement(sql);
        //5.执行sql 得到结果集
        ResultSet resultSet = statement.executeQuery();
        //6.处理结果集
        while (resultSet.next()){
            System.out.println(resultSet.getInt(1));
            System.out.println(resultSet.getString(2));
            System.out.println(resultSet.getString(3));
        }
        //7.关闭资源
        DBUtil.closeAll(resultSet,statement,connection);
    }
}
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