线程问题--（只让某一方法执行一次）

曾经终败给现在 2022-05-22 11:12 221阅读 0赞

package com.mmall.concurrency.example.atomic;  
  
  
import com.mmall.concurrency.annoations.ThreadSafe;  
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;  
import java.util.concurrent.atomic.AtomicBoolean;  
  
  
@Slf4j  
@ThreadSafe  
public class AtomicExample6 \{  
  
  
    private static AtomicBoolean isHappened = new AtomicBoolean(false);  
  
  
    // 请求总数  
    public static int clientTotal = 5000;  
  
  
    // 同时并发执行的线程数  
    public static int threadTotal = 200;  
  
  
    public static void main(String\[\] args) throws Exception \{  
        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();  
                    test();  
                    semaphore.release();  
                \} catch (Exception e) \{  
                \}  
                countDownLatch.countDown();  
            \});  
        \}  
        countDownLatch.await();  
        executorService.shutdown();  
        System.out.println("isHappened:\{\}"+ isHappened.get());  
    \}  
  
//该方法只会执行一次  
    private static void test() \{  
        if (isHappened.compareAndSet(false, true)) \{  
        System.out.println("execute");  
        \}  
    \}  
\}