JDBC learning

Reference resources b Stand Mr. Han Shunping jdbc Course

One 、 Connect to database

Mode one ：

Mode two

Mode three

Mode 4

Methods five

Two 、 Scribble

Summarize the interfaces and common methods

Transaction processing

package com.aylxx.jdbc.lx;

import com.aylxx.jdbc.utils.JDBCUtils;
import org.junit.jupiter.api.Test;

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


public class Founctiontest {
    
    @Test
    public void test01()  {
    
        Connection connection=null;
        PreparedStatement preparedStatement=null;
        String sql1="update account set money=money-100 where name=' Anyulong '";
        String sql2="update account set money=money+100 where name=' Fu Fu Xu '";

        try {
    
            connection= JDBCUtils.getConnection();
            connection.setAutoCommit(false);
            preparedStatement = connection.prepareStatement(sql1);
            preparedStatement.executeUpdate();
            int i=1/0;
            preparedStatement=connection.prepareStatement(sql2);
            preparedStatement.executeUpdate();
            connection.commit();
        } catch (SQLException e) {
    
            System.out.println(" An abnormal undo operation occurred ");
            try {
    
                connection.rollback();
            } catch (SQLException ex) {
    
                ex.printStackTrace();
            }
            e.printStackTrace();
        }finally {
    
            JDBCUtils.close(null,preparedStatement,connection);
        }

    }
}

jdbc tool kit
Prevent writing code that connects to the database again and again
convenient

package com.aylxx.jdbc.utils;

import java.io.FileInputStream;
import java.io.IOException;
import java.sql.*;
import java.util.Properties;

public class JDBCUtils {
    
    private  static  String user;
    private  static  String pwd;
    private  static  String url;
    private  static  String driver;

    static {
    

        try {
    
            Properties properties = new Properties();
            properties.load(new FileInputStream("src\\jdbc.properties"));
            user=properties.getProperty("user");
            pwd=properties.getProperty("password");
            url=properties.getProperty("url");
            driver=properties.getProperty("driver");
        } catch (IOException e) {
    
            throw new RuntimeException(e);

        }
    }
    public static Connection getConnection(){
    
        try {
    
            return DriverManager.getConnection(url,user,pwd);
        } catch (SQLException e) {
    
            throw new RuntimeException(e);
        }
    }
    public static void close(ResultSet resultSet, Statement statement,Connection connection){
    
        try {
    
            if(resultSet!=null)
            {
    
                resultSet.close();
            }
            if(statement!=null)
            {
    
                statement.close();
            }
            if(connection!=null){
    
                connection.close();
            }
        } catch (SQLException e) {
    
            throw new RuntimeException(e);
        }
    }

}

Batch application

Traditional processing time

@Test
    public void test01(){
    
        Connection connection=null;
        PreparedStatement preparedStatement=null;
        String sql="insert into ll values(?,?)";
        long start=System.currentTimeMillis();
        try {
    
            connection = JDBCUtils.getConnection();
            preparedStatement=connection.prepareStatement(sql);

            for (int i = 0; i < 5000; i++) {
    

            preparedStatement.setString(1,"ayl"+i);
            preparedStatement.setString(2,"666");
            preparedStatement.executeUpdate();

            }

        } catch (SQLException e) {
    
            e.printStackTrace();
        }finally {
    
            JDBCUtils.close(null,preparedStatement,connection);
        }
        long end=System.currentTimeMillis();
        System.out.println(end-start);
    }

Insert 5000 Data run time ：8684ms

The batch ： Yes preparedStatement Medium addbatch() Method , add to sql sentence ,executebatch() perform sql sentence ,clearbatch（） Empty sql sentence

 public void test01(){
    
        Connection connection=null;
        PreparedStatement preparedStatement=null;
        String sql="insert into ll values(?,?)";
        long start=System.currentTimeMillis();
        try {
    
            connection = JDBCUtils.getConnection();
            preparedStatement=connection.prepareStatement(sql);

            for (int i = 0; i < 5000; i++) {
    

            preparedStatement.setString(1,"ayl"+i);
            preparedStatement.setString(2,"666");
            preparedStatement.addBatch();
            if((i+1)%1000==0)
            {
    
                preparedStatement.executeBatch();
                preparedStatement.clearBatch();
            }


            }

        } catch (SQLException e) {
    
            e.printStackTrace();
        }finally {
    
            JDBCUtils.close(null,preparedStatement,connection);
        }
        long end=System.currentTimeMillis();
        System.out.println(end-start);
    }

The elapsed time ：1170ms

It can be seen that the efficiency of batch processing will be greatly improved when a large number of insert statements are executed .