使用CompletionService结合ExecutorService批处理任务

 1 import java.util.Random;
 2 import java.util.concurrent.Callable;
 3 import java.util.concurrent.CompletionService;
 4 import java.util.concurrent.ExecutionException;
 5 import java.util.concurrent.ExecutorCompletionService;
 6 import java.util.concurrent.ExecutorService;
 7 import java.util.concurrent.Executors;
 8  
 9 public class CallableAndFuture {
10  
11         public static void main(String[] args) {
12               ExecutorService threadPool = Executors. newFixedThreadPool(10);
13               CompletionService<Integer> completionService = new ExecutorCompletionService<Integer>(threadPool);
14  
15                for (int i = 0; i < 10; i++) {
16                       final int seq = i;
17                      System. out.println("开始提交第" + seq + "个任务");
18                      completionService.submit( new Callable<Integer>() {
19  
20                             @Override
21                             public Integer call() throws Exception {
22                                   Thread. sleep(new Random().nextInt(5000));
23                                    return seq;
24                            }
25                      });
26               }
27  
28                for (int i = 0; i < 10; i++) {
29                       try {
30                             // 取出并移除表示下一个已完成任务的 Future，如果目前不存在这样的任务，则等待。
31                            Integer seq = completionService.take().get();
32                            System. out.println("第" + seq + "个任务返回");
33                      } catch (InterruptedException e) {
34                            e.printStackTrace();
35                      } catch (ExecutionException e) {
36                            e.printStackTrace();
37                      }
38               }
39        }
40  
41 }