ExecutorService的execute和submit方法 怼烎@ 2022-08-07 11:42 204阅读 0赞 1、异常处理: ExecutorService的submit与execute方法都能执行任务,但在使用过程,发现其对待run方法抛出的异常处理方式不一样。 两者执行任务最后都会通过Executor的execute方法来执行,但对于submit,会将runnable物件包装成FutureTask<Object>,其run方法会捕捉被包装的Runnable Object的run方法抛出的Throwable异常,待submit方法所返回的的Future Object调用get方法时,将执行任务时捕获的Throwable Object包装成java.util.concurrent.ExecutionException来抛出。 而对于execute方法,则会直接抛出异常,该异常不能被捕获,想要在出现异常时做些处理,可以实现Thread.UncaughtExceptionHandler接口: class MyUncaughtExceptionHandler implements Thread.UncaughtExceptionHandler\{ public void uncaughtException(Thread t, Throwable e) \{ System.out.println("caught "+e); \} \} class HandlerThreadFactory implements ThreadFactory\{ public Thread newThread(Runnable r) \{ Thread t=new Thread(r); t.setUncaughtExceptionHandler(new MyUncaughtExceptionHandler()); return t; \} \} ExecutorService exec=Executors.newCachedThreadPool(new HandlerThreadFactory()) 转自:http://kavy.iteye.com/blog/2007563 2、有无返回值: submit有返回值,而execute没有 public class CallableTest \{ public static void main(String\[\] args) \{ ExecutorService executorService = Executors.newCachedThreadPool(); List<Future<String>> resultList = new ArrayList<Future<String>>(); // 创建10个任务并执行 for (int i = 0; i < 10; i++) \{ // 使用ExecutorService执行Callable类型的任务,并将结果保存在future变量中 Future<String> future = executorService.submit(new TaskWithResult(i)); // 将任务执行结果存储到List中 resultList.add(future); \} executorService.shutdown(); // 遍历任务的结果 for (Future<String> fs : resultList) \{ try \{ System.out.println("1111111111"+fs.get()); // 打印各个线程(任务)执行的结果 \} catch (InterruptedException e) \{ e.printStackTrace(); \} catch (ExecutionException e) \{ executorService.shutdownNow(); e.printStackTrace(); return; \} \} \} \} class TaskWithResult implements Callable<String> \{ private int id; public TaskWithResult(int id) \{ this.id = id; \} /\*\* \* 任务的具体过程,一旦任务传给ExecutorService的submit方法,则该方法自动在一个线程上执行。 \* \* @return \* @throws Exception \*/ public String call() throws Exception \{ System.out.println("call()方法被自动调用,干活!!! " + Thread.currentThread().getName()); // 一个模拟耗时的操作 for (int i = 999999999; i > 0; i--); return "call()方法被自动调用,任务的结果是:" + id + " " + Thread.currentThread().getName(); \} \} 转自:http://blog.csdn.net/peachpi/article/details/6771946
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