java多线程获取返回结果--Callable和Future示例

 package test.guyezhai.thread;

 import java.util.ArrayList;
 import java.util.Date;
 import java.util.List;
 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;

 @SuppressWarnings("unchecked")
 public class TestThread {

     @SuppressWarnings("rawtypes")
     public static void main(String[] args) throws ExecutionException, InterruptedException {
         System.out.println("----程序开始运行----");
         Date date1 = new Date();

         int taskSize = 50000;
         // 创建一个线程池
         ExecutorService pool = Executors.newFixedThreadPool(taskSize);
         // 创建多个有返回值的任务
         List<Future> list = new ArrayList<Future>();
         for (int i = 0; i < taskSize; i++) {
             Callable c = new MyCallable(i + " ");
             // 执行任务并获取Future对象
             Future f = pool.submit(c);
             // System.out.println(">>>" + f.get().toString());
             list.add(f);
         }
         // 关闭线程池
         pool.shutdown();

         // 获取所有并发任务的运行结果
         for (Future f : list) {
             // 从Future对象上获取任务的返回值，并输出到控制台
             System.out.println(">>>" + f.get().toString());
         }

         Date date2 = new Date();
         System.out.println("----程序结束运行----，程序运行时间【" + (date2.getTime() - date1.getTime()) + "毫秒】");
     }
 }

 class MyCallable implements Callable<Object> {
     private String taskNum;

     MyCallable(String taskNum) {
         this.taskNum = taskNum;
     }

     @Override
     public Object call() throws Exception {
         System.out.println(">>>" + taskNum + "任务启动");
         Date dateTmp1 = new Date();
         Thread.sleep(1000);
         Date dateTmp2 = new Date();
         long time = dateTmp2.getTime() - dateTmp1.getTime();
         System.out.println(">>>" + taskNum + "任务终止");
         return taskNum + "任务返回运行结果,当前任务时间【" + time + "毫秒】";
     }
 }