小编naw*_*low的帖子

我处于这样一种情况,我需要使用java.concurrent包中的Semaphore,以便我可以限制占用某个资源的线程数.以下是非常基本的设置(代码):

    package semaphor;

    import java.util.concurrent.Semaphore;

    /**
     * Created by NawazishMohammad on 15-04-2015.
     */
    public class SemaphoreTester {
       public static void main (String [] args){
           new Thread(new MyRunnable(), "T1").start();
           new Thread(new MyRunnable(), "T2").start();
           new Thread(new MyRunnable(), "T3").start();
           new Thread(new MyRunnable(), "T4").start();
       }
    }

    class MyRunnable implements Runnable{

        @Override
        public void run() {
            semaphoreStatus();
        }

        public void semaphoreStatus(){
            System.out.println("Thread waiting for permit: "+Thread.currentThread().getName());
            Semaphore sem = new Semaphore(2);
            try {
                sem.acquire();
                System.out.println("Thread got permit: " + Thread.currentThread().getName());
                System.out.println("Thread releasing permit: "+Thread.currentThread().getName());
                sem.release(); …

由于某种原因,java.util.concurrent.ExecutorCompletionService它不使用java.util.concurrent.ExecutorService线程池中的线程.这会影响ExecutorCompletionService.submit()方法调用的"阻塞"执行.请考虑以下代码:

package completionservicedemo1;

import java.util.Date;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorCompletionService;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;

public class CompletionServiceDemo1 {

    static final ExecutorService executor = Executors.newFixedThreadPool(10, new ThreadFactory() {

        @Override
        public Thread newThread(Runnable r) {
            Thread thread = new Thread(r);
            thread.setName("Executor-Thread");
            try {
                System.out.println("Thread going to sleep: "+Thread.currentThread().getName());
                thread.sleep(5000L);
                System.out.println("Thread awakened: "+Thread.currentThread().getName());
            } catch (InterruptedException ex) {
                System.out.println("InteruptedException: "+ex);
            }
            return thread;
        }
    });

    static final ExecutorCompletionService<String> completionService = new ExecutorCompletionService<>(executor);
    static byte val=1;

    public …