Runnable,Callable,Future,RunnableFuture,FutureTask,ExecutorService的关系

本文主要是介绍Runnable,Callable,Future,RunnableFuture,FutureTask,ExecutorService的关系，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

关系

Executor就是Runnable和Callable的调度容器，Future就是对于具体的调度任务的执行结果进行查看，最为关键的是Future可以检查对应的任务是否已经完成，也可以阻塞在get方法上一直等待任务返回结果。Runnable和Callable的差别就是Runnable是没有结果可以返回的，就算是通过Future也看不到任务调度的结果的。

FutureTask则是一个RunnableFuture<V>，即实现了Runnbale又实现了Futrue<V>这两个接口，另外它还可以包装Runnable和Callable<V>，所以一般来讲是一个符合体了，它可以通过Thread包装来直接执行，也可以提交给ExecuteService来执行，并且还可以通过v get()返回执行结果，在线程体没有执行完成的时候，主线程一直阻塞等待，执行完则直接返回结果。

开启线程的几种方法:

1.通过继承Thread类开启线程

  /*** 通过继承Thread类开启线程*/private void extendsThread() {new MyThread().start();}class MyThread extends Thread{@Overridepublic void run() {super.run();System.out.println("通过继承Thread类开启线程");}}

2.Runnable+Thread

  /*** 通过new Thread(runnable)开启线程*/private void runnableThread() {new Thread(new Runnable() {@Overridepublic void run() {System.out.println("通过new Thread(runnable)开启线程");}}).start();}

3.Callable+FutureTask+Thread

    /*** 通过new Thread(new FutureTask(callable))开启线程*/private void callableFutureTaskThread() {FutureTask<String> futureTask = new FutureTask<String>(new Callable<String>() {@Overridepublic String call() throws Exception {System.out.println("通过new Thread(new FutureTask(callable))开启线程");return "finish 通过new Thread(new FutureTask(callable))开启线程";}});new Thread(futureTask).start();try {System.out.println(futureTask.get());} catch (InterruptedException e) {e.printStackTrace();} catch (ExecutionException e) {e.printStackTrace();}}

4.ExecutorService+Callable+Future

 /*** 通过 executorService.submit(callable)并且return一个Future开启线程*/private void executorServiceCallableFuture() {ExecutorService executorService = Executors.newFixedThreadPool(5);//创建一个可重用固定线程数的线程池;Future<String> future = executorService.submit(new Callable<String>() {@Overridepublic String call() throws Exception {System.out.println("通过 executorService.submit(callable)并且return一个Future开启线程");return "finish 通过 executorService.submit(callable)并且return一个Future开启线程";}});try {System.out.println(future.get());} catch (InterruptedException e) {e.printStackTrace();} catch (ExecutionException e) {e.printStackTrace();}}

5.ExecutorService+Runnable+Future

 /*** 通过 executorService.submit(runnable,T)并且return一个Future开启线程*/private void executorServiceRunnableFuture() {ExecutorService executorService = Executors.newFixedThreadPool(5);//创建一个可重用固定线程数的线程池;Future<String> future = executorService.submit(new Runnable() {@Overridepublic void run() {System.out.println("通过 executorService.submit(runnable,T)并且return一个Future开启线程");}},"finish 通过 executorService.submit(runnable,T)并且return一个Future开启线程");try {System.out.println(future.get());} catch (InterruptedException e) {e.printStackTrace();} catch (ExecutionException e) {e.printStackTrace();}}

6.ExecutorService+FutureTask

 /*** 通过 executorService.submit(futureTask)开启线程*/private void executorServiceFutureTask() {ExecutorService executorService = Executors.newFixedThreadPool(5);//创建一个可重用固定线程数的线程池;FutureTask<String> futureTask = new FutureTask<String>(new Callable<String>() {@Overridepublic String call() throws Exception {System.out.println("通过 executorService.submit(futureTask)开启线程");return "通过 executorService.submit(futureTask)开启线程";}});executorService.submit(futureTask);try {System.out.println(futureTask.get());} catch (InterruptedException e) {e.printStackTrace();} catch (ExecutionException e) {e.printStackTrace();}}

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