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ThreadPoolExecutor的execute()和submit()方法_threadpoolexecutor.execute

作者：IT小白 | 2024-08-20 22:51:26

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threadpoolexecutor.execute

我希望使用多线程执行一个运算，并且线程执行完毕后我要获取执行结果。其实使用线程池ThreadPoolExecutor的execute()和submit()方法都可以。

使用execute()的话，事先定义一个存放返回结果的集合，开辟线程时，将集合的元素作为参数代入自定义的Runnable接口的实现类中，多线程执行完毕后遍历集合即可获得运算结果。

使用submit()的话，可以在submit()中执行一个Callable接口的实现类，submit()方法可以返回一个Future<> future，然后使用future.get()方法获得返回结果，由于future.get()会使调用线程池的线程阻塞，等待返回结果，所以可以先将Future<> future放入一个集合，等多线程执行完毕后再遍历集合获得运算结果。

使用execute()方法：

定义一个结果类：

  1. public class RunResult {
  2.     // 输入参数
  3.     private Integer param;
  4.     // 是否运算成功
  5.     private Boolean success;
  6.     // 运算结果
  7.     private Integer result;
  8.     public Integer getParam() {
  9.         return param;
  10.     }
  11.     public void setParam(Integer param) {
  12.         this.param = param;
  13.     }
  14.     public Boolean getSuccess() {
  15.         return success;
  16.     }
  17.     public void setSuccess(Boolean success) {
  18.         this.success = success;
  19.     }
  20.     public Integer getResult() {
  21.         return result;
  22.     }
  23.     public void setResult(Integer result) {
  24.         this.result = result;
  25.     }
  26. }

定义一个Runnable接口的实现类：

  1. public class MyRunnable implements Runnable {
  2.     // 运算结果类
  3.     private RunResult result;
  4.     // 线程同步器
  5.     private CountDownLatch main;
  6.     @Override
  7.     public void run() {
  8.         String name = Thread.currentThread().getName();
  9.         System.out.println(name + " 线程开始执行" + "-" + result.getParam());
  10.         for (int i = 0; i < 1; i++) {
  11.             for (int j = 1; j <= 200000000; j++) {
  12.                 if (j == 200000000 && null != result.getParam()) {
  13.                     result.setResult(result.getParam()*10);
  14.                     result.setSuccess(true);
  15.                     System.out.println(name + " 线程正在进行计算" + "-" + result.getParam());
  16.                 } else {
  17.                     result.setSuccess(false);
  18.                 }
  19.             }
  20.         }
  21.         System.out.println(name + " 线程执行完毕" + "-" + result.getParam());
  22.         main.countDown();
  23.     }
  24.     public MyRunnable(RunResult result, CountDownLatch main) {
  25.         super();
  26.         this.result = result;
  27.         this.main = main;
  28.     }
  29.     public MyRunnable() {
  30.         super();
  31.     }
  32. }

main方法：

  1.     public static void main(String[] args) {
  2.         ThreadPoolExecutor threadPool = new ThreadPoolExecutor(6, 10, 10L, TimeUnit.SECONDS, 
  3.                 new LinkedBlockingQueue<Runnable>(20),
  4.                 Executors.defaultThreadFactory(), 
  5.                 new ThreadPoolExecutor.CallerRunsPolicy());
  6.         // 存放结果类的集合
  7.         List<RunResult> list = new ArrayList<RunResult>(12);
  8.         // 线程同步器
  9.         CountDownLatch main = new CountDownLatch(12);
  10.         for (int i = 1; i <= 12; i++) {
  11.             RunResult result = new RunResult();
  12.             result.setParam(i);
  13.             list.add(result);
  14.             MyRunnable runnable = new MyRunnable(result,main);
  15.             threadPool.execute(runnable);
  16.         }
  17.         try {
  18.             main.await();
  19.             System.out.println(JSON.toJSON(list));
  20.             // 线程池不用了，关闭线程池
  21.             threadPool.shutdown();
  22.             //threadPool.shutdownNow();
  23.         } catch (InterruptedException e) {
  24.             
  25.         }
  26.     }

执行结果：

  1. pool-1-thread-1 线程开始执行-1
  2. pool-1-thread-5 线程开始执行-5
  3. pool-1-thread-3 线程开始执行-3
  4. pool-1-thread-2 线程开始执行-2
  5. pool-1-thread-4 线程开始执行-4
  6. pool-1-thread-6 线程开始执行-6
  7. pool-1-thread-1 线程正在进行计算-1
  8. pool-1-thread-1 线程执行完毕-1
  9. pool-1-thread-1 线程开始执行-7
  10. pool-1-thread-6 线程正在进行计算-6
  11. pool-1-thread-6 线程执行完毕-6
  12. pool-1-thread-6 线程开始执行-8
  13. pool-1-thread-5 线程正在进行计算-5
  14. pool-1-thread-5 线程执行完毕-5
  15. pool-1-thread-5 线程开始执行-9
  16. pool-1-thread-3 线程正在进行计算-3
  17. pool-1-thread-3 线程执行完毕-3
  18. pool-1-thread-3 线程开始执行-10
  19. pool-1-thread-4 线程正在进行计算-4
  20. pool-1-thread-4 线程执行完毕-4
  21. pool-1-thread-4 线程开始执行-11
  22. pool-1-thread-2 线程正在进行计算-2
  23. pool-1-thread-2 线程执行完毕-2
  24. pool-1-thread-2 线程开始执行-12
  25. pool-1-thread-5 线程正在进行计算-9
  26. pool-1-thread-5 线程执行完毕-9
  27. pool-1-thread-4 线程正在进行计算-11
  28. pool-1-thread-4 线程执行完毕-11
  29. pool-1-thread-2 线程正在进行计算-12
  30. pool-1-thread-2 线程执行完毕-12
  31. pool-1-thread-6 线程正在进行计算-8
  32. pool-1-thread-3 线程正在进行计算-10
  33. pool-1-thread-3 线程执行完毕-10
  34. pool-1-thread-1 线程正在进行计算-7
  35. pool-1-thread-6 线程执行完毕-8
  36. pool-1-thread-1 线程执行完毕-7
  37. [{"result":10,"param":1,"success":true},{"result":20,"param":2,"success":true},{"result":30,"param":3,"success":true},{"result":40,"param":4,"success":true},{"result":50,"param":5,"success":true},{"result":60,"param":6,"success":true},{"result":70,"param":7,"success":true},{"result":80,"param":8,"success":true},{"result":90,"param":9,"success":true},{"result":100,"param":10,"success":true},{"result":110,"param":11,"success":true},{"result":120,"param":12,"success":true}]

使用submit()方法：

返回结果类同上

定义一个Callable接口的实现类：

  1. public class MyCallable implements Callable<RunResult> {
  2.     // 运算结果类
  3.     private RunResult result;
  4.     // 线程同步器
  5.     private CountDownLatch main;
  6.     @Override
  7.     public RunResult call() throws Exception {
  8.         String name = Thread.currentThread().getName();
  9.         System.out.println(name + " 线程开始执行" + "-" + result.getParam());
  10.         for (int i = 0; i < 1; i++) {
  11.             for (int j = 1; j <= 200000000; j++) {
  12.                 if (j == 200000000 && null != result.getParam()) {
  13.                     result.setResult(result.getParam()*10);
  14.                     result.setSuccess(true);
  15.                     System.out.println(name + " 线程正在进行计算" + "-" + result.getParam());
  16.                 } else {
  17.                     result.setSuccess(false);
  18.                 }
  19.             }
  20.         }
  21.         System.out.println(name + " 线程执行完毕" + "-" + result.getParam());
  22.         main.countDown();
  23.         return result;
  24.     }
  25.     public MyCallable(RunResult result, CountDownLatch main) {
  26.         super();
  27.         this.result = result;
  28.         this.main = main;
  29.     }
  30.     public MyCallable() {
  31.         super();
  32.     }
  33. }

main方法：

  1.     public static void main(String[] args) {
  2.         ThreadPoolExecutor threadPool = new ThreadPoolExecutor(6, 10, 10L, TimeUnit.SECONDS, 
  3.                 new LinkedBlockingQueue<Runnable>(20),
  4.                 Executors.defaultThreadFactory(), 
  5.                 new ThreadPoolExecutor.CallerRunsPolicy());
  6.         // 存放Future<>的集合
  7.         List<Future<RunResult>> list = new ArrayList<Future<RunResult>>(12);
  8.         // 线程同步器
  9.         CountDownLatch main = new CountDownLatch(12);
  10.         for (int i = 1; i <= 12; i++) {
  11.             RunResult result = new RunResult();
  12.             result.setParam(i);
  13.             MyCallable callable = new MyCallable(result,main);
  14.             Future<RunResult> runResultFuture = threadPool.submit(callable);
  15.             list.add(runResultFuture);
  16.         }
  17.         try {
  18.             main.await();
  19.             for (int i = 0; i < list.size(); i++) {
  20.                 RunResult runResult = list.get(i).get();
  21.                 System.out.println(JSON.toJSON(runResult));
  22.             }
  23.             // 线程池不用了，关闭线程池
  24.             threadPool.shutdown();
  25.             //threadPool.shutdownNow();
  26.         } catch (InterruptedException e) {
  27.             
  28.         } catch (ExecutionException e) {
  29.             
  30.         }
  31.     }

执行结果：

  1. pool-1-thread-3 线程开始执行-3
  2. pool-1-thread-4 线程开始执行-4
  3. pool-1-thread-2 线程开始执行-2
  4. pool-1-thread-1 线程开始执行-1
  5. pool-1-thread-5 线程开始执行-5
  6. pool-1-thread-6 线程开始执行-6
  7. pool-1-thread-1 线程正在进行计算-1
  8. pool-1-thread-3 线程正在进行计算-3
  9. pool-1-thread-5 线程正在进行计算-5
  10. pool-1-thread-5 线程执行完毕-5
  11. pool-1-thread-2 线程正在进行计算-2
  12. pool-1-thread-2 线程执行完毕-2
  13. pool-1-thread-6 线程正在进行计算-6
  14. pool-1-thread-6 线程执行完毕-6
  15. pool-1-thread-4 线程正在进行计算-4
  16. pool-1-thread-4 线程执行完毕-4
  17. pool-1-thread-6 线程开始执行-9
  18. pool-1-thread-5 线程开始执行-7
  19. pool-1-thread-2 线程开始执行-8
  20. pool-1-thread-3 线程执行完毕-3
  21. pool-1-thread-3 线程开始执行-11
  22. pool-1-thread-1 线程执行完毕-1
  23. pool-1-thread-1 线程开始执行-12
  24. pool-1-thread-4 线程开始执行-10
  25. pool-1-thread-6 线程正在进行计算-9
  26. pool-1-thread-5 线程正在进行计算-7
  27. pool-1-thread-5 线程执行完毕-7
  28. pool-1-thread-1 线程正在进行计算-12
  29. pool-1-thread-1 线程执行完毕-12
  30. pool-1-thread-4 线程正在进行计算-10
  31. pool-1-thread-2 线程正在进行计算-8
  32. pool-1-thread-3 线程正在进行计算-11
  33. pool-1-thread-6 线程执行完毕-9
  34. pool-1-thread-3 线程执行完毕-11
  35. pool-1-thread-2 线程执行完毕-8
  36. pool-1-thread-4 线程执行完毕-10
  37. {"result":10,"param":1,"success":true}
  38. {"result":20,"param":2,"success":true}
  39. {"result":30,"param":3,"success":true}
  40. {"result":40,"param":4,"success":true}
  41. {"result":50,"param":5,"success":true}
  42. {"result":60,"param":6,"success":true}
  43. {"result":70,"param":7,"success":true}
  44. {"result":80,"param":8,"success":true}
  45. {"result":90,"param":9,"success":true}
  46. {"result":100,"param":10,"success":true}
  47. {"result":110,"param":11,"success":true}
  48. {"result":120,"param":12,"success":true}

参考博客：ThreadPoolExecutor中的submit()方法详细讲解

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