数据库连接池DBCP

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使用数据库连接池方式与普通方式对比

package com.micro.profession.jdbc.practice;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import org.apache.commons.dbcp2.BasicDataSource;

//继承Thread父类
public class DBPoolDbcpImpl extends Thread{

    public static BasicDataSource ds = null;

    static final String DRIVER_NAME = "com.mysql.jdbc.Driver";
    static final String DB_URL = "jdbc:mysql://localhost/cloud_study";
    static final String USER_NAME = "root";
    static final String PASSWORD = "123456";

    public static void dbpoolInit() {
        ds = new BasicDataSource();
        ds.setUrl(DB_URL);
        ds.setDriverClassName(DRIVER_NAME);
        ds.setUsername(USER_NAME);
        ds.setPassword(PASSWORD);
        ds.setMaxTotal(2);
    }

    //数据库连接池方式，ds
    public void dbPoolTest() {
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        try {
            conn = ds.getConnection();
            stmt = conn.createStatement();
            rs = stmt.executeQuery("select * from user");
            while (rs.next()) {
                System.out.println(rs.getString("userName"));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (conn != null)
                    conn.close();
                if (stmt != null)
                    stmt.close();
                if (rs != null)
                    rs.close();

            } catch (SQLException e) {
                // ignore
            }
        }

    }

    //普通方式连接数据库
    public void jdbcTest() {
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        try {
            Class.forName(DRIVER_NAME);
            conn = DriverManager.getConnection(DB_URL, USER_NAME, PASSWORD);
            stmt = conn.createStatement();
            rs = stmt.executeQuery("select * from user");
            while (rs.next()) {
                System.out.println(rs.getString("userName"));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } catch (Exception e1) {
            // ignore
        } finally {
            try {
                if (conn != null)
                    conn.close();
                if (stmt != null)
                    stmt.close();
                if (rs != null)
                    rs.close();

            } catch (SQLException e) {
                // ignore
            }
        }
    }

    //重写父类的run()方法。在run()方法中加入具体的任务代码或处理逻辑。
    public void run() {
        long start = System.currentTimeMillis();
        while (System.currentTimeMillis() - start < 10000) {
//          jdbcTest();
            dbPoolTest();
        }
    }

    public static void main(String[] args) {        
        dbpoolInit();
        // 开启10个线程Thread
        // 调用start方法，线程t启动，隐含的调用run()方法。
        for(int i =0 ;i<10 ;i++){
            new DBPoolDbcpImpl().start();
        }

    }

}

DBCP与JDBC驱动，maven引用

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.18</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.commons/commons-dbcp2 -->
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-dbcp2</artifactId>
    <version>2.1.1</version>
</dependency>

程序运行之后，在mysql中使用show processlist;查看线程情况。

1.使用普通方式jdbcTest();有10个线程

2.使用连接池dbPoolTest();只有设置的2个线程