一、ThreadPoolExecutor 简要实例
获取子线程执行结果后再执行主线程 ,这样可将复杂耗时业务拆分执行返回结果,将结果汇总整理。
多个线程时可以 利用Future阻塞,当其它线程执行完毕获得结果,再执行主线程
/** * ThreadPoolExecutor 线程池使用 * 1、多个线程时可以 利用Future阻塞,当其它线程执行完毕获得结果,再执行主线程 */ @Test public void simpleMethod() { ThreadPoolExecutor poolExecutor = new ThreadPoolExecutor(9, 100, 100, TimeUnit.SECONDS, new SynchronousQueue<>()); try { List<String> list1 = new ArrayList<String>(); Callable<Integer> call1 = new Callable<Integer>() { @Override public Integer call() throws Exception { for (int j = 0; j < 10; j++) { list1.add("i:" + j); } return 10; } }; Callable<Integer> call2 = new Callable<Integer>() { @Override public Integer call() throws Exception { for (int j = 0; j < 10; j++) { list1.add("i:" + j); } return 10; } }; Callable<Integer> call3 = new Callable<Integer>() { @Override public Integer call() throws Exception { for (int j = 0; j < 10; j++) { list1.add("i:" + j); } return 10; } }; Callable<Integer> call4 = new Callable<Integer>() { @Override public Integer call() throws Exception { for (int j = 0; j < 10; j++) { list1.add("i:" + j); } return 10; } }; Future<Integer> f1 = poolExecutor.submit(call1); Future<Integer> f2 = poolExecutor.submit(call2); Future<Integer> f3 = poolExecutor.submit(call3); Future<Integer> f4 = poolExecutor.submit(call3); ArrayList<String> ss = new ArrayList<>(); f1.get(); f2.get(); f3.get(); f4.get(); // Thread.sleep(1000); System.out.println("list1.size() = " + list1.size()); } catch (Exception e) { e.printStackTrace(); } }
二、CountDownLanch 简要实例
场景:当指定几个线程执行完后再执行 主线程,或使用2个CountDownLanch 对象进行多组子线程控制
/** * CountDownLatch 阻塞执行完预其的线程才会执行,后续方法业务处理 */ @Test public void lanchTest() { try { ThreadPoolExecutor thredPool = new ThreadPoolExecutor(20, 100, 1000, TimeUnit.SECONDS, new ArrayBlockingQueue<>(10)); CountDownLatch cutdownLanch = new CountDownLatch(3); thredPool.execute(new Runnable() { @Override public void run() { System.out.println("我是子线程-id:" + Thread.currentThread().getName()); cutdownLanch.countDown(); } }); thredPool.execute(new Runnable() { @Override public void run() { System.out.println("我是子线程-id:" + Thread.currentThread().getName()); cutdownLanch.countDown(); } }); thredPool.execute(new Runnable() { @Override public void run() { System.out.println("我是子线程-id:" + Thread.currentThread().getName()); cutdownLanch.countDown(); } }); System.out.println("这是主线程在下一句阻塞,current-thread-id:" + Thread.currentThread().getName()); cutdownLanch.await(); System.out.println("子线程执行完毕"); } catch (InterruptedException e) { e.printStackTrace(); } }
ps: 线程池各参数 先估算,再加上压力测试进行调整 。