java-mysql 使用druid连接池-查询数据

druid jar包下载：https://repo1.maven.org/maven2/com/alibaba/druid/

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package com.quan.app;

import com.alibaba.druid.pool.DruidDataSourceFactory;
import com.quan.pojo.Brand;
import org.junit.jupiter.api.Test;

import javax.sql.DataSource;
import java.io.FileInputStream;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;

public class BrandTest {


    // 查询所有数据
    @Test
    public void testSelectAll() throws Exception {
        // 加载配置文件
        Properties prop = new Properties();
        prop.load(new FileInputStream("src/druid.properties"));

        //获取连接池对象
        DataSource dataSource = DruidDataSourceFactory.createDataSource(prop);

        // 获取数据库连接对象
        Connection conn = dataSource.getConnection();

        // 执行sql语句
        String sql = "select * from tb_brand";
        PreparedStatement preparedStatement = conn.prepareStatement(sql);
        ResultSet resultSet = preparedStatement.executeQuery();


        List<Brand> list = new ArrayList<>();
        while (resultSet.next()){
            // 获取数据
            int id = resultSet.getInt("id");
            String brandName = resultSet.getString("brand_name");
            String companyName = resultSet.getString("company_name");
            int ordered = resultSet.getInt("ordered");
            int status = resultSet.getInt("status");

            Brand brand = new Brand();
            brand.setId(id);
            brand.setBrandName(brandName);
            brand.setCompanyName(companyName);
            brand.setOrdered(ordered);
            brand.setStatus(status);

            list.add(brand);
        }

        // 释放资源
        resultSet.close();
        preparedStatement.close();
        conn.close();

        System.out.println(list);
    }

}

//输出
5月 09, 2022 1:58:49 上午 com.alibaba.druid.pool.DruidDataSource info
信息: {dataSource-1} inited
[Brand{id=1, brandName='三只松鼠', companyName='三只松鼠有限公司', ordered=5, description='null', status=1}, Brand{id=2, brandName='华为', companyName='华为技术有限公司', ordered=100, description='null', status=1}, Brand{id=3, brandName='小米', companyName='小米科技有限公司', ordered=50, description='null', status=1}]

进程已结束,退出代码0