java通过Callable和Future来接收线程池的执行结果

package com.hys.test;
 
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
 
import com.google.common.util.concurrent.ThreadFactoryBuilder;
 
public class Test {
 
  private static AtomicInteger num = new AtomicInteger();
 
  public static void main(String[] args) throws InterruptedException, ExecutionException {
    CountDownLatch latch = new CountDownLatch(1000);
    ThreadFactory namedThreadFactory = new ThreadFactoryBuilder().setNameFormat("increment-pool-%d").build();
    ExecutorService poolexecutor = new ThreadPoolExecutor(1000, 1000, 0L, TimeUnit.MILLISECONDS, new LinkedBlockingQueue(1024), namedThreadFactory, new ThreadPoolExecutor.AbortPolicy());
    Future submit = null;
    for (int i = 0; i < 1000; i++) {
      if (submit != null && submit.get() != null) {
        latch.countDown();
        continue;
      }
      submit = poolexecutor.submit(() -> {
        try {
          //这里模拟一个耗时很长的操作
          num.getAndIncrement();
          //int a = 1 / 0;
          Thread.sleep(1);
          return null;
        } catch (Exception e) {
          return e.toString();
        } finally {
          latch.countDown();
        }
      });
    }
    poolexecutor.shutdown();
    //主线程等待所有分线程执行完毕后再执行
    latch.await();
    String errorMsg = submit.get();
    //如果子线程在执行过程中有错误，则在此抛出该异常
    if (errorMsg != null) {
      throw new RuntimeException(errorMsg);
    }
    System.out.println(num);
  }
}