Druid 连接池 JDBCUtils 工具类的使用

2023-05-16

Druid工具介绍

它不仅仅是一个数据库连接池，它还包含一个ProxyDriver，一系列内置的JDBC组件库，一个SQL Parser。支持所有JDBC兼容的数据库，包括Oracle、MySQL、Derby、Postgresql、SQL Server、H2等等。 Druid针对oracle和mysql做了特别优化，比如Oracle的PS Cache内存占用优化，MySql的ping检测优化。Druid提供了MySql、Oracle、Postgresql、SQL-92的SQL的完整支持，这是一个手写的高性能SQL Parser，支持Visitor模式，使得分析SQL的抽象语法树很方便。简单SQL语句用时10微秒以内，复杂SQL用时30微秒。通过Druid提供的SQL Parser可以在JDBC层拦截SQL做相应处理，比如说分库分表、审计等。Druid防御SQL注入攻击的WallFilter就是通过Druid的SQL Parser分析语义实现的

性能上图标分析

这个图标是从别人的blog上面copy过了，这个是sql语句进行1000次以后的查询提醒druid 连接池的性能分析，大家可以做为参考，是否准确待定。。

工具的使用

这个是在代码中去注册一些配置信息，不常用的大家随便看看就好


package com.ruirui.druid;

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

import org.junit.Test;

import com.alibaba.druid.pool.DruidDataSource;
import com.ruirui.decoratedesgin.Utils;

public class DruidDemo {
    @Test
    public void druidTest(){
        Connection conn = null;
        PreparedStatement pstmt = null;
        ResultSet rs = null;
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName("com.mysql.jdbc.Driver");
        dataSource.setUrl("jdbc:mysql:///stu");
        dataSource.setUsername("root");
        dataSource.setPassword("123456");
        try{
            // 获得连接:
            conn = dataSource.getConnection();
            // 编写SQL：
            String sql = "select * from student";
            pstmt = conn.prepareStatement(sql);
            // 执行sql:
            rs = pstmt.executeQuery();
            while(rs.next()){
                System.out.println(rs.getInt("id")+"   "+rs.getString("name"));
            }
        }catch(Exception e){
            e.printStackTrace();
        }finally{

            Utils.releaseResouce(rs, ps
tmt, conn);
        }

    }

}

注册信息在配置文件中


@Test
    public void demo2(){
        Connection conn = null;
        PreparedStatement pstmt = null;
        ResultSet rs = null;

        try{
            Properties properties = new Properties();
            properties.load(new FileInputStream("src/druid.properties"));
            DataSource dataSource = DruidDataSourceFactory.createDataSource(properties);
            // 获得连接:
            conn = dataSource.getConnection();
            // 编写SQL：
            String sql = "select * from account";
            pstmt = conn.prepareStatement(sql);
            // 执行sql:
            rs = pstmt.executeQuery();
            while(rs.next()){
                System.out.println(rs.getInt("id")+"   "+rs.getString("name")+"   "+rs.getDouble("money"));
            }
        }catch(Exception e){
            e.printStackTrace();
        }finally{
            JDBCUtils.release(rs, pstmt, conn);
        }
    }

配置文件


driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql:///day04
username=root
password=123

这里配置信息有很多 最大连接数量 ， 最小连接数量等。。。配置的信息很多啊 大家可以去读一下官方文档。。 跟C3P0使用的情况 基本上都差不多

> 这里是下载地址druid 文档 jar包  http://pan.baidu.com/s/1jHYEPpk

JDBCUtils工具类的使用


package com.ruirui.jdbcutils;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.Arrays;
import java.util.List;
import java.util.Map;

import javax.sql.DataSource;

import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.ArrayHandler;
import org.apache.commons.dbutils.handlers.ArrayListHandler;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.ColumnListHandler;
import org.apache.commons.dbutils.handlers.KeyedHandler;
import org.apache.commons.dbutils.handlers.MapHandler;
import org.apache.commons.dbutils.handlers.MapListHandler;
import org.apache.commons.dbutils.handlers.ScalarHandler;
import org.junit.Test;

import com.mchange.v2.c3p0.ComboPooledDataSource;

public class JDBCUtils {
    /**
     *   QueryRunner：核心执行类
     *   ResultSetHandler：提供对查询结果封装
     *   DbUtils    ：工具类
     */

    //c3p0 连接池
    public DataSource comboPooledDataSource = new ComboPooledDataSource();

    public Connection getConn() throws SQLException{

        return comboPooledDataSource.getConnection();
    }

    //插入数据
    public void saveData() throws SQLException {

        QueryRunner queryRunner = new QueryRunner(comboPooledDataSource);

        String sql = "insert into student values(null,'ruirui',?,?);";

        queryRunner.update(sql, "shenyang",27);
    }

    // 修改表

    public void fixData() throws SQLException{

        QueryRunner queryRunner = new QueryRunner(comboPooledDataSource);
        String sql = "update student set name=? where id=?;";
        queryRunner.update(sql,"pp", 13);
    }


    // 删除操作
    public void demo3() throws SQLException{
        QueryRunner queryRunner = new QueryRunner(comboPooledDataSource);
        String sql ="delete from account where id =?";
        queryRunner.update(sql, 4);
    }


    // ArrayHandler:将查询到的一条记录封装到数组当中
    public void demo1() throws SQLException{
        QueryRunner queryRunner = new QueryRunner(comboPooledDataSource);
        String sql  = "select * from account where id = ?";
        Object[] objs = queryRunner.query(sql, new ArrayHandler(), 1); // ”1“ 代表一条数据
        System.out.println(Arrays.toString(objs));
    }

    //ArrayListHandler 
    //一条查询是ArrayHandler 一个数组
    //多条查询 就是将多个数组 存入集合中
    public void demo2() throws SQLException {
        QueryRunner queryRunner = new QueryRunner(comboPooledDataSource);
        String sql  = "select * from student";

        List<Object[]> query = queryRunner.query(sql, new ArrayListHandler());

        for (Object[] objects : query) {

            for (Object object : objects) {
                System.out.println(object.toString());
            }
        }
    }

    //查询一条记录 返回的是一个bean对象
    public void demo4() throws SQLException {
        QueryRunner queryRunner = new QueryRunner(comboPooledDataSource);
        String sql  = "select * from student where id = ?";
        Man man = queryRunner.query(sql, new BeanHandler<>(Man.class),5);
        System.out.println(man.toString());
    }

    //注意返回的是一个标准的javabean对象，所在定义bean对象时候成员变量必须用private定义

    //查询一条记录 返回的是一个bean对象
    public void demo5() throws SQLException {
        QueryRunner queryRunner = new QueryRunner(comboPooledDataSource);
        String sql  = "select * from student";
        List<Man> query = queryRunner.query(sql, new BeanListHandler<>(Man.class ));
        System.out.println(query.toString());
    }

    // MapHandler:封装一条记录到Map中
    public void demo6()throws SQLException{
        QueryRunner queryRunner = new QueryRunner(comboPooledDataSource);
        String sql = "select * from student where id = ?";
        Map<String,Object> map = queryRunner.query(sql, new MapHandler() ,2);
        System.out.println(map);
    } 

    // MapListHandler: //查询多条 将map集合存入list 集合中
    public void demo7()throws SQLException{
        QueryRunner queryRunner = new QueryRunner(comboPooledDataSource);
        String sql = "select * from student";
        List<Map<String,Object>> list = queryRunner.query(sql, new MapListHandler());
        for (Map<String, Object> map : list) {
            System.out.println(map);
        }
    }

    // ColumnListHandler ,返回的是一个列值的集合
    public void demo8()throws SQLException{
        QueryRunner queryRunner = new QueryRunner(comboPooledDataSource);
        String sql = "select id from student";
        List<Object> list  = queryRunner.query(sql, new ColumnListHandler());
        for (Object object : list) {
            System.out.println(object.toString());
        }
    }

    //ScalarHandler：单值查询
    public void demo9()throws SQLException{
        QueryRunner queryRunner = new QueryRunner(comboPooledDataSource);
        String sql = "select sum(age) from student;";
        Long count = (Long)queryRunner.query(sql, new ScalarHandler());
        System.out.println(count);
    }
    @Test
    // KeyedHandler:
    public void demo10()throws SQLException{
        QueryRunner queryRunner = new QueryRunner(comboPooledDataSource);
        String sql = "select * from student";
        Map<Object,Map<String,Object>> map= queryRunner.query(sql, new KeyedHandler("name"));
        for (Object key : map.keySet()) {
            System.out.println(key + "   "+map.get(key));
        }
    }

}

JDBUtils 文档以及jar 下载链接

http://pan.baidu.com/s/1c13IXxu

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