多线程ExecutorService中submit和execute区别

爱被打了一巴掌 2022-05-29 10:45 186阅读 0赞

*  介绍
    
    submit和execute都是 ExecutorService 的方法，都是添加线程到线程池中。
 *  区别   
    submit 有返回值 返回future ， execute没有
 *  submit 返回值 future 用处   
    可以执行cancle方法，取消执行   
    可以通过get()方法，判断是否执行成功 ==null表示执行成功

import java.util.concurrent.ExecutionException;
    import java.util.concurrent.ExecutorService;
    import java.util.concurrent.Executors;
    import java.util.concurrent.Future;
    
    public class ThreadPoolDemo { 
    
        class ThreadDemo implements Runnable { 
    
            public void run()
            {
                System.err.println("hello world");
            }
    
        }
    
        public static void main(String[] args)
        {
            ExecutorService executorService = Executors.newFixedThreadPool(2);
    
            ThreadPoolDemo threadPoolDemo = new ThreadPoolDemo();
            for (int i = 0; i < 5; i++)
            {
                ThreadDemo threadDemo = threadPoolDemo.new ThreadDemo();
                Future future = executorService.submit(threadDemo);
    
                // 可以取消执行
                future.cancel(true);
    
                // 可以获取返回结果，如果future.get()!=null 且无异常，表示执行成功
                try
                {
                    if (future.get() == null) System.out.println("执行完成");
                }
                catch (InterruptedException e)
                {
                    e.printStackTrace();
                }
                catch (ExecutionException e)
                {
                    e.printStackTrace();
                }
            }
        }
    }