Java BasePooledObjectFactory对象池化技术如何使用

Java GenericObjectPool 对象池化技术--SpringBoot sftp 连接池工具类

一个对象池包含一组已经初始化过且可以使用的对象，而可以在有需求时创建和销毁对象。池的用户可以从池子中取得对象，对其进行操作处理，并在不需要时归还给池子而非直接销毁它。这是一种特殊的工厂对象。

BasePooledObjectFactory 对象池化技术的使用

Pom.xml

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-pool2</artifactId>
    <version>2.7.0</version>
</dependency>

MqttConnection.java

package com.vipsoft.mqtt.pool;
 
public class MqttConnection {

    private String mqttClient;
    ;

    public MqttConnection(String mqttClient) {
        this.mqttClient = mqttClient;
    }

    public String getMqttClient() {
        return mqttClient;
    }

    public void setMqttClient(String mqttClient) {
        this.mqttClient = mqttClient;
    }

    /**
     * 推送方法消息
     */
    public void publish(String msg) throws Exception {
        System.out.println("对象" + mqttClient + ":" + "执行任务" + msg);
    }

    @Override
    public String toString() {
        return "MqttConnection{" + "id=" + mqttClient + '}';
    }
}

MqttConnectionFactory.java

package com.vipsoft.mqtt.pool;

import org.apache.commons.pool2.BasePooledObjectFactory;
import org.apache.commons.pool2.PooledObject;
import org.apache.commons.pool2.impl.DefaultPooledObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.concurrent.atomic.AtomicInteger;

public class MqttConnectionFactory extends BasePooledObjectFactory<MqttConnection> {

    private static final Logger logger = LoggerFactory.getLogger(MqttConnectionFactory.class);


    // AtomicInteger是一个提供原子操作的Integer类，通过线程安全的方式操作加减
    private AtomicInteger counter = new AtomicInteger();

    /**
     * 在对象池中创建对象
     *
     * @return
     * @throws Exception
     */
    @Override
    public MqttConnection create() throws Exception {

        // 实现线程安全避免在高并发的场景下出现clientId重复导致无法创建连接的情况
        int count = this.counter.addAndGet(1);
        MqttConnection mqttConnection = new MqttConnection("MqttConnection：" + count);
        logger.info("在对象池中创建对象 {}", mqttConnection.toString());
        return mqttConnection;
    }

    /**
     * common-pool2 中创建了 DefaultPooledObject 对象对对象池中对象进行的包装。
     * 将我们自定义的对象放置到这个包装中，工具会统计对象的状态、创建时间、更新时间、返回时间、出借时间、使用时间等等信息进行统计
     *
     * @param mqttConnection
     * @return
     */
    @Override
    public PooledObject<MqttConnection> wrap(MqttConnection mqttConnection) {
        logger.info("封装默认返回类型 {}", mqttConnection.toString());
        return new DefaultPooledObject<>(mqttConnection);
    }

    /**
     * 销毁对象
     *
     * @param p 对象池
     * @throws Exception 异常
     */
    @Override
    public void destroyObject(PooledObject<MqttConnection> p) throws Exception {
        logger.info("销毁对象 {}", p.getObject().getMqttClient());
        super.destroyObject(p);
    }

    /**
     * 校验对象是否可用
     *
     * @param p 对象池
     * @return 对象是否可用结果，boolean
     */
    @Override
    public boolean validateObject(PooledObject<MqttConnection> p) {
        logger.info("校验对象是否可用 {}", p.getObject().getMqttClient());
        return super.validateObject(p);
    }

    /**
     * 激活钝化的对象系列操作
     *
     * @param p 对象池
     * @throws Exception 异常信息
     */
    @Override
    public void activateObject(PooledObject<MqttConnection> p) throws Exception {
        logger.info("激活钝化的对象 {}", p.getObject().getMqttClient());
        super.activateObject(p);
    }

    /**
     * 钝化未使用的对象
     *
     * @param p 对象池
     * @throws Exception 异常信息
     */
    @Override
    public void passivateObject(PooledObject<MqttConnection> p) throws Exception {
        logger.info("钝化未使用的对象 {}", p.getObject().getMqttClient());
        super.passivateObject(p);
    }
}

PoolTest.java

package com.vipsoft.mqtt;

import cn.hutool.core.date.DateUtil;
import com.vipsoft.mqtt.pool.MqttConnection;
import com.vipsoft.mqtt.pool.MqttConnectionFactory;
import org.apache.commons.pool2.impl.GenericObjectPool;
import org.apache.commons.pool2.impl.GenericObjectPoolConfig;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.atomic.AtomicInteger;

@SpringBootTest
public class PoolTest {

    @Test
    void basePooledTest() throws InterruptedException {

        AtomicInteger atomicInteger = new AtomicInteger();

        int excutorCount = 15;
        CountDownLatch countDownLatch = new CountDownLatch(excutorCount);

        // =====================创建线程池=====================
        ExecutorService excutor = Executors.newFixedThreadPool(5);
        // =====================创建对象池 项目中使用了InitializingBean.afterPropertiesSet() 中创建=====================
        // 对象池工厂
        MqttConnectionFactory personPoolFactory = new MqttConnectionFactory();
        // 对象池配置
        GenericObjectPoolConfig<MqttConnection> objectPoolConfig = new GenericObjectPoolConfig<>();
        objectPoolConfig.setMaxTotal(50);
        // 对象池
        GenericObjectPool<MqttConnection> mqttPool = new GenericObjectPool<>(personPoolFactory, objectPoolConfig);
        // =====================测试对象池=====================
        // 循环100次，从线程池中取多个多线程执行任务，来测试对象池
        for (int i = 0; i < excutorCount; i++) {
            excutor.submit(new Thread(() -> {
                // 模拟从对象池取出对象，执行任务
                MqttConnection mqtt = null;
                try {
                    // 从对象池取出对象
                    mqtt = mqttPool.borrowObject();
                    // 让对象工作
                    int count = atomicInteger.addAndGet(1);
                    mqtt.publish("Id:" + count + " Time: " + DateUtil.now());
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    // 回收对象到对象池
                    if (mqtt != null) {
                        mqttPool.returnObject(mqtt);
                    }
                    countDownLatch.countDown();
                }
            }));
        }
        countDownLatch.await();
    }
}

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