ExecutorService的submit(Runnable x)和execute(Runnable x) 两个方法的本质区别

Runnable任务没有返回值，而Callable任务有返回值。并且Callable的call()方法只能通过ExecutorService的submit(Callable <T> task) 方法来执行

public class RunnableTestMain {

    public static void main(String[] args) {

        ExecutorService pool = Executors.newFixedThreadPool(2);

        /**

         * execute(Runnable x) 没有返回值。可以执行任务，但无法判断任务是否成功完成。

         */

        pool.execute(new RunnableTest("Task1")); 

        /**

         * submit(Runnable x) 返回一个future。可以用这个future来判断任务是否成功完成。请看下面：

         */

        Future future = pool.submit(new RunnableTest("Task2"));

        try {

            if(future.get()==null){//如果Future's get返回null，任务完成

                System.out.println("任务完成");

            }

        } catch (InterruptedException e) {

        } catch (ExecutionException e) {

            //否则我们可以看看任务失败的原因是什么

            System.out.println(e.getCause().getMessage());

        }

    }

}

public class RunnableTest implements Runnable {

    private String taskName;

    public RunnableTest(final String taskName) {

        this.taskName = taskName;

    }

    @Override

    public void run() {

        System.out.println("Inside "+taskName);

        throw new RuntimeException("RuntimeException from inside " + taskName);

    }

}