java ExecutorService学习

废话少说：

1.ExecutorService.shutdown与ExecutorService.shutdownNow的区别？

ExecutorService.shutdown 停止接收新的task提交，完成已提交的task

ExecutorService.shutdownNow 停止接收新的task,并停止线程池中已提交的task

正确的关闭ExecutorService流程

public static void shutdownAndAwaitTermination(ExecutorService es) {  
        es.shutdown(); // Disable new tasks from being submitted  不再接受新的提交
        try {  
            // Wait a while for existing tasks to terminate  
            if (!es.awaitTermination(BaseConstants.AWAIT_TIME, TimeUnit.MILLISECONDS)) {  
                es.shutdownNow(); // Cancel currently executing tasks  
                // Wait a while for tasks to respond to being cancelled  
                if (!es.awaitTermination(BaseConstants.AWAIT_TIME, TimeUnit.MILLISECONDS))  
                    System.err.println("Pool did not terminate");  
            }  
        } catch (InterruptedException ie) {  
            // (Re-)Cancel if current thread also interrupted  
            es.shutdownNow();  
            // Preserve interrupt status  
            Thread.currentThread().interrupt();  
        }  
    }  

有新的补