java jdbc druid 连接池 连接工具类的编写 连接池版

文件结构

配置信息

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/mybank?useUnicode=true&characterEncoding=utf8
username=root
password=root123
initialSize=3
maxActive=7
maxWait=3000

连接工具类

package tools;

import com.alibaba.druid.pool.DruidDataSourceFactory;

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

public class DbUtils {
    // 变量的定义
    // 集合
    private static Properties properties = new Properties();
    // 连接池
    private static DataSource ds;

    // 静态代码块
    static {
        // 获取配置流文件
        InputStream resourceAsStream = DbUtils.class.getClassLoader().getResourceAsStream("tools/base.properties");
        try {
            // 集合加载配置
            properties.load(resourceAsStream);
            // 给变量ds重新赋值
            ds = DruidDataSourceFactory.createDataSource(properties);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }


    // 获取连接池
    public static DataSource getDs() {
        return ds;
    }

    // 获取连接对象
    public static Connection getConnection() {
        try {
            return ds.getConnection();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        return null;
    }

    // 归还连接对象
    public static void close(Connection connection) {
        if (connection == null) {
            return;
        }
        try {
            connection.close();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
    }
}

测试类

import tools.DbUtils;

import javax.sql.DataSource;
import java.sql.Connection;

public class Test {
    public static void main(String[] args) {
        // 获取连接池
        DataSource ds = DbUtils.getDs();
        System.out.println(ds);

        // 获取连接对象
        Connection connection = DbUtils.getConnection();
        System.out.println(connection);

        // 归还连接对象
        DbUtils.close(connection);
        System.out.println("game over");
    }
}

最终效果

"C:\Program Files\Java\jdk1.8.0_172\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2021.1.3\lib\idea_rt.jar=65300:C:\Program Files\JetBrains\IntelliJ IDEA 2021.1.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_172\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_172\jre\lib\rt.jar;D:\Program_java\untitled30\out\production\untitled30;D:\Program_java\untitled30\lib\druid-1.0.9.jar;D:\Program_java\untitled30\lib\mysql-connector-java-5.1.0-bin.jar" Test
{
  CreateTime:"2023-03-16 23:49:56",
  ActiveCount:0,
  PoolingCount:0,
  CreateCount:0,
  DestroyCount:0,
  CloseCount:0,
  ConnectCount:0,
  Connections:[
  ]
}
三月 16, 2023 11:49:56 下午 com.alibaba.druid.pool.DruidDataSource info
信息: {dataSource-1} inited
com.mysql.jdbc.JDBC4Connection@e73f9ac
game over

Process finished with exit code 0