Druid数据库连接池的使用 (MYSQL --version=8.0.20)

（1）jar 包下载

链接：https://pan.baidu.com/s/1UiqV9fNAxjPpD4rxXuFOUA 提取码：zfco

（2）druid.properties配置文件

// mysql 8.0驱动
driverClassName=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/db01?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT
username=root
password=mysql
maxActive=5
maxWait=2000
initialSize=3
minIdle=2

（3）工具类封装

package com.itcast.utils;

import com.alibaba.druid.pool.DruidDataSourceFactory;

import javax.sql.DataSource;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

public class JDBCUtils {
    public static DataSource ds;

    static {
        Properties properties = new Properties();
        try {
            InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
            properties.load(is);
            ds = DruidDataSourceFactory.createDataSource(properties);
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static DataSource getDataSource(){
        return ds;
    }

    public static Connection getConnection() throws SQLException {
        return ds.getConnection();
    }
}

（4）目录结构

（5）简单demo

import com.java.utils.JDBCUtils;
import org.junit.Test;

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

public class DruidTest {

    @Test
    public void testDruid() throws SQLException {
        Connection conn = JDBCUtils.getConnection();
        String sql = "select * from user";
        PreparedStatement ps = conn.prepareStatement(sql);
        ResultSet resultSet = ps.executeQuery();

        while (resultSet.next()){
            String username = resultSet.getString("username");
            String password = resultSet.getString("password");
            System.out.println(username + " : " + password);
        }
    }
}