Java Callable的使用

 1 import java.util.ArrayList;
 2 import java.util.concurrent.Callable;
 3 import java.util.concurrent.ExecutionException;
 4 import java.util.concurrent.ExecutorService;
 5 import java.util.concurrent.Executors;
 6 import java.util.concurrent.Future;
 7 
 8 
 9 public class CallableTest{
10     public static void main(String[] args) {
11         ExecutorService executorService=    //创建线程池
12                 Executors.newCachedThreadPool();
13         ArrayList<Future<String>> list=
14                 new ArrayList<Future<String>>();
15         for (int i = 0; i < 10; i++) {
16             list.add(executorService    //通过submit方法来提交Callable到线程池中执行
17                     .submit(new TaskWithResult()));
18         }
19         for (Future<String> future : list) {
20             try {
21                 System.out.println(future.get()); //通过get方法来获取call返回值
22             } catch (InterruptedException e) {
23                 e.printStackTrace();
24             } catch (ExecutionException e) {
25                 e.printStackTrace();
26             }
27         }
28     }
29 
30     
31     static class TaskWithResult implements Callable<String>{
32         private static int taskNum=0;
33         private int taskId=taskNum;
34         public TaskWithResult() {
35             taskNum++;
36         }
37 
38         @Override
39         public String call() throws Exception {
40             try {
41                 Thread.sleep(this.taskId*1000);    //我制造的时间差，更直观地显示call和run方法的相似性。
42             } catch (InterruptedException e) {
43                 e.printStackTrace();
44             }
45             return "Result of TaskWithResult： "+this.taskId;
46         }
47         
48     } 
49 
50 }