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(); } } } }