2回答

Jimin

2018-07-21

你好，你少写了countDownLatch里特别关键的countDown方法的调用，导致主线程一直阻塞在await那里了。关于这个类的使用，后面课程里会有专门章节重点介绍。祝你学习愉快～

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慕粉3495297

提问者

2018-07-21

具体代码如下

package com.mmall.concurrency;

import lombok.extern.slf4j.Slf4j;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;

@Slf4j
public class ConcurrencyTest {
    // 请求总数
    public static int clientTotal = 5000;

    // 同时并发执行的线程数
    public static int threadTotal = 200;

    //计数值
    public static int count = 0;

    public static void main(String[] args) throws Exception {
        //线程池

        ExecutorService executorService = Executors.newCachedThreadPool();
        final Semaphore semaphore = new Semaphore(threadTotal);
        final CountDownLatch countDownLatch = new CountDownLatch(clientTotal);
        for (int i = 0; i < clientTotal; i++) {
            executorService.execute(() -> {
                try {
                    semaphore.acquire();
                    add();
                    log.info("count11:{}", count);
                    semaphore.release();
                } catch (Exception e) {
                    log.error("exception: ", e);
                }

            });`
        }
        countDownLatch.await();
        executorService.shutdown();
        log.info("count: {}", count);
    }

    public static void add() {
        count++;
    }
}

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