Callable 和 Future

通过 Future可以获取 Callable 返回的结果
 future.get() 可以阻塞线程，使线程等待结果。

package cn.itcast.heima2;

import java.util.Random;
import java.util.concurrent.Callable;
import java.util.concurrent.CompletionService;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorCompletionService;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;



public class CallableAndFuture {

    /**
     * @param args
     */
    public static void main(String[] args) {
        ExecutorService threadPool = Executors.newSingleThreadExecutor();
        Future<String> future =
            threadPool.submit(
                new Callable<String>() {
                    public String call() throws Exception {
                        Thread.sleep(2000);
                        return "hello";
                    };
                }
        );
        System.out.println("等待结果");
        try {
            System.out.println("拿到结果：" + future.get());
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }




}