java - Scanner.nextInt()块

如果采用以下方式，我的代码可以正常工作。

Scanner input = new Scanner(System.in);
ExecutorService executor = Executors.newFixedThreadPool(2);
for (int i = 0; i < 3; i++)
{
     Runnable worker = new ClassA();
     executor.execute(worker);
}

相反，我想在while(true)循环中连续运行，并在用户输入1时中断循环。我尝试了以下方法，但是它不起作用。它不是连续运行，而是在此行停止(阻止)int stop = input.nextInt();有人可以告诉我错误在哪里。无论这是否是正确的方法，如果不是，请提出替代方案。我在A类中的代码连接到jms queue，并应不断从队列中读取消息。

Scanner input = new Scanner(System.in);
ExecutorService executor = Executors.newFixedThreadPool(2);
while(true)
{
     Runnable worker = new ClassA();
     executor.execute(worker);
     int stop = input.nextInt();
     if(stop == 1) {
            break;
     }
 }

编辑:以下是已编辑的代码。当输入scanner.nextInt()值1时，完成= true。虽然(!finished)循环中断，但其中的代码未执行，但我的Consumer类仍在连续运行。

public class ScannerProblem {
   public static boolean finished = false;
   static class Listener implements Runnable {
      Scanner scanner = new Scanner(System.in);
      @Override
        public void run() {
            while (true) {
                System.out.println("scanning");
                if (scanner.nextInt() == 1) {
                    System.out.println("scanning finished");
                    finished = true;
                    return;
                } else {
                    System.out.println("scanned something strange");
                    try {
                        Thread.sleep(1500);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    }

    static class Consumer implements Runnable {
        javax.jms.Connection jmsConnection = null;
        private static ProcessRequest processRequest = new ProcessRequest();
        @Override
        public void run() {
            ActiveMQConnection con = new ActiveMQConnection();
            jmsConnection = con.openTcpConnection();
            try {
                String json = null;
                Session session = jmsConnection.createSession(false,
                        Session.AUTO_ACKNOWLEDGE);
                Queue queue = session.createQueue("Upload_Queue");
                MessageConsumer consumer = session.createConsumer(queue);
                TextMessage message = (TextMessage) consumer.receive();
                System.out.println("Message #" + ": " + message.getText());
                json = message.getText();
                processRequest.upload(json);
                System.out.println("Thread ID: " +                 Thread.currentThread().getId());

            if (jmsConnection != null) {

                    jmsConnection.close();
            }

            Thread.sleep(5000);
        }
            catch(JMSException e) {
                e.printStackTrace();
            }
            catch(InterruptedException e){
                e.printStackTrace();
            }
            catch(Exception e) {
                e.printStackTrace();
            }
            }
    }



    public static void main(String[] args) {
        ExecutorService pool = Executors.newFixedThreadPool(2);
        pool.submit(new Listener());

        while (!finished) {
            System.out.println("finished::"+finished);
            pool.submit(new Consumer());
            try {
                Thread.sleep(4000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

最佳答案

int stop = input.nextInt()是阻塞调用，因此它仅执行一次可运行的ClassA，然后等待输入。

您需要将输入代码移至另一个线程，以免阻塞ClassA的执行。

也许更好的选择是仅执行一个ClassA执行，并在其中执行另一个while(true)循环。

关于java - Scanner.nextInt()块，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/34946088/