【JDBC】3.工具类-JDBCUtils

将获取连接操作代码

        //提供Properties，并加载指定配置文件的流
        Properties pros = new Properties();
        InputStream is = ClassLoader.getSystemClassLoader().getResourceAsStream("druid.properties");
        //加载
        pros.load(is);

        //通过DruidDataSourceFactory创建一个数据源
        DataSource dataSource = DruidDataSourceFactory.createDataSource(pros);

        //通过数据源获取连接
        Connection connection = dataSource.getConnection();
        return connection;

JDBCUtils 类

package com.atguigu.java1.util;

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 JDBCUtils {

    
    public static Connection getConnection() throws Exception {

        //通过数据源获取连接
        Connection connection = dataSource.getConnection();
        return connection;
    }


    private static DataSource dataSource ;

    static{//静态代码块
        //提供Properties，并加载指定配置文件的流
        try {
            Properties pros = new Properties();
            InputStream is = ClassLoader.getSystemClassLoader().getResourceAsStream("druid.properties");
            pros.load(is);

            //由于静态代码块只执行一次，所以我们自始至终就创建过一个DataSource
            dataSource = DruidDataSourceFactory.createDataSource(pros);
            
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    //关闭连接
    public static void close(Connection connection){
        if(connection != null){
            try {
                connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

}

测试工具类

package com.atguigu.java1.test;

import com.atguigu.java1.util.JDBCUtils;
import org.junit.Test;

import java.sql.Connection;


public class JDBCUtilsTest {
    @Test
    public void test1() throws Exception {
        Connection connection = JDBCUtils.getConnection();

        System.out.println(connection);
    }
}