ThreadPoolExecutor的execute()和submit()方法

ThreadPoolExecutor的execute()和submit()方法

 

本文链接：https://blog.csdn.net/m0_37822338/article/details/100010495

 

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