Question

我有一个数据库结果，每个呼叫可创建500条记录 500，然后是下一个500，然后是下一个

我需要在每个记录中运行一条不同的线程来完成特定任务

我的例子如下

List<Users> users =  find 500 users

ExecutorService执行程序= Executors.newFixedThreadPool（10）;

//for each users 
for ( int i =0 ; i<users.size(); i++) {
 Runnable worker = new MyWorker(users.get(i));
 executor.execute(worker);
}

//MyWorker.java

class MyWorker implements Runnable {
User user;

MyWorker(User user)
  this.user = user;
}

@Override
public void run() {
   system.out.println("Start);
    processCommand(this.user);
   system.out.println("End);
}

processCommand(User user){
 //processing
}

}

我的问题是，在完成当前的执行程序服务之前，它会获取下500个用户并尝试开始处理，我需要停止该操作，直到处理了前500个记录，然后启动下一个缓冲池

Answer 1

您应该尝试使用至少可以编译的代码。无论如何，听起来您可以使用CountDownLatch等待线程完成，然后再移至下一个500。

private void myfunc(List<User> users) throws InterruptedException {
    ExecutorService executor = Executors.newFixedThreadPool(10);

    CountDownLatch countDownLatch = new CountDownLatch(users.size());
    for ( int i =0 ; i<users.size(); i++) {
        Runnable worker = new MyWorker(users.get(i), countDownLatch);
        executor.execute(worker);
    }
    countDownLatch.await();

}
class MyWorker implements Runnable {
    User user;
    CountDownLatch countDownLatch;

    MyWorker(User user, CountDownLatch countDownLatch) {
      this.user = user;
        this.countDownLatch = countDownLatch;
    }

    @Override
    public void run() {
        System.out.println("Start");
        processCommand(this.user);
        countDownLatch.countDown();
        System.out.println("End");
    }

    void processCommand(User user){
        //processing
    }
}

Java执行器服务

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