异步返回结果测试demo

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import java.util.HashMap;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

/** 
 * @date 创建时间：2017年2月7日 上午11:33:11 
 * @Description: 
 */
public class FutureTest {

    public static void main(String[] args) throws InterruptedException, ExecutionException {

        //通过线程池管理多线程
        ExecutorService threadPool = Executors.newFixedThreadPool(2);

        //线程池提交一个异步任务
        System.out.println("====提交异步任务");
        Future<HashMap<String,String>> future = threadPool.submit(new Callable<HashMap<String,String>>() {

            @Override
            public HashMap<String,String> call() throws Exception {

                System.out.println("异步任务开始执行....");
                Thread.sleep(10000);
                System.out.println("异步任务执行完毕，返回执行结果!!!!");

                return new HashMap<String,String>(){
                    {this.put("futureKey", "成功获取future异步任务结果");}
                };
            }

        });

        System.out.println("====提交异步任务之后，立马返回到主线程继续往下执行");
        Thread.sleep(1000);


        boolean flag = true;
        while(flag){
            //异步任务完成并且未被取消，则获取返回的结果
            if(future.isDone() && !future.isCancelled()){
                HashMap<String,String> futureResult = future.get();
                System.out.println("====异步任务返回的结果是："+futureResult.get("futureKey"));
                flag = false;
            }
        }

        //关闭线程池
        if(!threadPool.isShutdown()){
            threadPool.shutdown();
        }
    }
}