Question

我正在努力弄清楚如何集中资源，我开始怀疑我的线程可能是问题（不是100％，而是在试验它）。我要做的就是为服务器创建一个通道池，然后查看线程是否正在使用它们。我已经成功地获得了为我上传的多个项目创建的频道数量（即它没有汇集，只是在每个线程中创建新频道）并成功创建了一个频道（即没有汇集或创建新频道）根据需要的渠道）。

我在想也许线程与池交互的方式是问题所以我试图创建newCachedThreadPool所以线程不会因为工作而死，但是当我这样做时我会得到错误说通道被用作关闭。在我的池中有一个destroyObject方法，但我从来没有调用它，所以我不明白为什么它会被触发（如果我发表评论它然后它可以工作，但只创建一个频道，上传速度非常慢，约300次操作/秒与没有线程池我得到30k /秒）。我怀疑它是终止的，有没有办法验证这个，如果它终止，我可以使用一个替代品吗？

这是代码（忽略所有rabbitmq的东西，它只是让我可以监控结果）：

import org.apache.commons.pool.BasePoolableObjectFactory;
import org.apache.commons.pool.ObjectPool;
import org.apache.commons.pool.PoolableObjectFactory;
import org.apache.commons.pool.impl.GenericObjectPool;

import java.io.IOException;
import java.util.NoSuchElementException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;


import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.MessageProperties;

public class PoolExample {

    private static ExecutorService executor_worker;

    static {
        final int numberOfThreads_ThreadPoolExecutor = 20;
        executor_worker = Executors.newCachedThreadPool();
        executor_worker = new ThreadPoolExecutor(numberOfThreads_ThreadPoolExecutor, numberOfThreads_ThreadPoolExecutor, 1000, TimeUnit.SECONDS,
                                           new LinkedBlockingDeque<Runnable>());
    }

    private static ObjectPool<Channel> pool;

    public static void main(String[] args) throws Exception {
        System.out.println("starting..");           
        ObjectPool<Channel> pool =
                new GenericObjectPool<Channel>(
                new ConnectionPoolableObjectFactory(), 50);
        for (int x = 0; x<500000000; x++) {
            executor_worker.submit(new MyRunnable(x, pool));
        }
        //executor_worker.shutdown();
        //pool.close();
    }
}

 class ConnectionPoolableObjectFactory extends BasePoolableObjectFactory<Channel> {
     Channel channel;
     Connection connection;

    public ConnectionPoolableObjectFactory() throws IOException {
        System.out.println("hello world");
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        channel = connection.createChannel(); 
    }

    @Override
    public Channel makeObject() throws Exception {  
        //channel = connection.createChannel(); 
        return channel; 
    }

    @Override
    public boolean validateObject(Channel channel) {
        return channel.isOpen();
    }

    @Override
    public void destroyObject(Channel channel) throws Exception {
        channel.close();
    }

    @Override
    public void passivateObject(Channel channel) throws Exception {
        //System.out.println("sent back to queue");
    }
}

class MyRunnable implements Runnable{  
    protected int x = 0;
    protected ObjectPool<Channel> pool;

    public MyRunnable(int x, ObjectPool<Channel> pool) {
        // TODO Auto-generated constructor stub
        this.x = x;
        this.pool = pool;
    }

    public void run(){
        try {
                Channel channel = pool.borrowObject();
                String message = Integer.toString(x);
                channel.basicPublish( "", "task_queue", 
                        MessageProperties.PERSISTENT_TEXT_PLAIN,
                        message.getBytes());
                pool.returnObject(channel);
        } catch (NoSuchElementException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IllegalStateException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 
    }
}

P.S。我基本上问了几个问题并阅读了文档并尝试解决这个问题，并且我可能完全走错了方向，所以如果你看到任何问题或提示，请按我的方式发送。

情节变粗：

在main方法的for循环中（我将工作提交给线程）我添加了：

    Set<Thread> threadSet = Thread.getAllStackTraces().keySet();
    System.out.println(threadSet.size()); //number of threads
    System.out.println(pool.getNumActive());

它向我展示了25个线程（虽然我说20个）和池中的20个项目。但是当我查看rabbitmq UI时，我看到一个只有一个通道的连接。如果我创建频道并提交给runnable，那么它会创建许多频道（但它永远不会关闭它们）。我不明白发生了什么，为什么结果不如预期。

Answer 1

我认为问题是你的ConnectionPoolableObjectFactory只创建一个Channel对象。似乎每次调用makeObject时都应该创建一个新的频道。

所以也许应该实现这样的东西：

public class ConnectionPoolableObjectFactory
        extends BasePoolableObjectFactory<Channel> {

    private final Connection connection;

    private ConnectionPoolableObjectFactory() {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        connection = factory.newConnection();
    }

    @Override
    public Channel makeObject() throws Exception {
        return connection.createChannel();
    }

    @Override
    public boolean validateObject(Channel channel) {
        return channel.isOpen();
    }

    @Override
    public void destroyObject(Channel channel) throws Exception {
        channel.close();
    }

    @Override
    public void passivateObject(Channel channel) throws Exception {
        //System.out.println("sent back to queue");
    }
}

这假设每个工厂从单个连接创建多个通道。

newFixedThreadPool与对象池无法正常工作

1 个答案: