线程池执行方法要慎用(submit,execute)

比眉伴天荒 2021-12-22 10:39 477阅读 0赞

# 案例 #

ExecutorService executorService = new ThreadPoolExecutor(10, 50, 0L, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>(), new DefaultThreadFactory(""));
    
            Thread thread=new Thread(new Runnable() {
                @Override
                public void run() {
                    System.out.println(1);
                    int i=1/0;
                    System.out.println(2);
                }
            });
            executorService.submit(thread);
    
            executorService.execute(thread);

# 结果 #

submit:没有抛出异常

execute:会抛出异常

# 坑 #

如果使用submit的话，到时线上报错都是没有看到的。

# 看下原因 #

## submit ##

/**
         * Submits a Runnable task for execution and returns a Future
         * representing that task. The Future's {@code get} method will
         * return {@code null} upon <em>successful</em> completion.
         *
         * @param task the task to submit
         * @return a Future representing pending completion of the task
         * @throws RejectedExecutionException if the task cannot be
         *         scheduled for execution
         * @throws NullPointerException if the task is null
         */
        Future<?> submit(Runnable task);

看到了?，返回的是Future，call有个返回值

我们可以executorService.submit(thread).get()，来获取返回值

结果就报错出来了，nice

## execute ##

/**
         * Executes the given command at some time in the future.  The command
         * may execute in a new thread, in a pooled thread, or in the calling
         * thread, at the discretion of the {@code Executor} implementation.
         *
         * @param command the runnable task
         * @throws RejectedExecutionException if this task cannot be
         * accepted for execution
         * @throws NullPointerException if command is null
         */
        void execute(Runnable command);

# 总结 #

一般使用execute进行提交执行，如果使用submit的话要获取返回结果