FutureTask一例

package com.journaldev.threads;import java.util.concurrent.Callable;public class MyCallable implements Callable<String> {private long waitTime;public MyCallable(int timeInMillis){this.waitTime=timeInMillis;}@Overridepublic String call() throws Exception {Thread.sleep(waitTime);        //return the thread name executing this callable task        return Thread.currentThread().getName();}}

package com.journaldev.threads;import java.util.concurrent.ExecutionException;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.FutureTask;import java.util.concurrent.TimeUnit;import java.util.concurrent.TimeoutException;public class FutureTaskExample {public static void main(String[] args) {MyCallable callable1 = new MyCallable(1000);MyCallable callable2 = new MyCallable(2000);FutureTask<String> futureTask1 = new FutureTask<String>(callable1);FutureTask<String> futureTask2 = new FutureTask<String>(callable2);ExecutorService executor = Executors.newFixedThreadPool(2);executor.execute(futureTask1);executor.execute(futureTask2);while (true) {try {if(futureTask1.isDone() && futureTask2.isDone()){System.out.println("Done");//shut down executor serviceexecutor.shutdown();return;}if(!futureTask1.isDone()){//wait indefinitely for future task to completeSystem.out.println("FutureTask1 output="+futureTask1.get());}System.out.println("Waiting for FutureTask2 to complete");String s = futureTask2.get(200L, TimeUnit.MILLISECONDS);if(s !=null){System.out.println("FutureTask2 output="+s);}} catch (InterruptedException | ExecutionException e) {e.printStackTrace();}catch(TimeoutException e){//do nothing}}}}

输出：

FutureTask1 output=pool-1-thread-1
Waiting for FutureTask2 to complete
Waiting for FutureTask2 to complete
Waiting for FutureTask2 to complete
Waiting for FutureTask2 to complete
Waiting for FutureTask2 to complete
FutureTask2 output=pool-1-thread-2
Done

原文：http://www.javacodegeeks.com/2013/07/java-futuretask-example-program.html