How to stop all runnable thread in java executor class?

multithreading java executorservice

2022-09-03 00:19:21

final ExecutorService executor = Executors.newFixedThreadPool(1);
final Future<?> future = executor.submit(myRunnable);
executor.shutdown();
if(executor.awaitTermination(10, TimeUnit.SECONDS)) {
  System.out.println("task completed");
}else{
  System.out.println("Executor is shutdown now");
}

//MyRunnable method is defined as task which I want to execute in a different thread.

Here is method of executor class:run

public void run() {
try {
     Thread.sleep(20 * 1000);
} catch (InterruptedException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
}}

Here it is waiting for second but when i run the code it throws an exception:20

java.lang.InterruptedException: sleep interrupted
at java.lang.Thread.sleep(Native Method)

I am not able to close the concurrent thread ruining in . Here is my Code flow:Java Executor class

Created a new Thread with Java executor class to run some task i.e written in MyRunnable
executor wait for 10 second to complete the tasks.
If the task has completed then runnable thread also got terminated.
If the task is not completed within 10 second then class should terminate the thread.executor

Everything works fine except the termination of tasks in the last scenario. How should I do it?

答案 1

The shutDown() method simply prevents additional tasks from being scheduled. Instead, you could call shutDownNow() and check for thread interruption in your .Runnable

// in your Runnable...
if (Thread.interrupted()) {
  // Executor has probably asked us to stop
}

An example, based on your code, might be:

final ExecutorService executor = Executors.newFixedThreadPool(1);
executor.submit(new Runnable() {
  public void run() {
    try {
      Thread.sleep(20 * 1000);
    } catch (InterruptedException e) {
      System.out.println("Interrupted, so exiting.");
    }
  }
});

if (executor.awaitTermination(10, TimeUnit.SECONDS)) {
  System.out.println("task completed");
} else {
  System.out.println("Forcing shutdown...");
  executor.shutdownNow();
}

答案 2

It is generally a bad idea to terminate a running thread from the outside, because you don't know the state the thread is currently in. It's possible that it needs to do some cleanups, and it won't be able to do that when you forcefully shut it down. That's why all methods of Thread which do that are marked as deprecated.

It's much better to use one of the many techniques which are available for interprocess communication to signal the procedure running in the thread itself that it has to abort its work and exit normally. One way to do this is to add an method to your runnable, which raises a flag declared as . The inner loop of your Runnable checks that flag and exits (in a controlled fashion) when that flag is raised.abort()volatile