Java多线程ThreadPoolExecutor如何正确使用？

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ExecutorService的使用javapublic class ThreadPoolDemo { public static void main(String[] args) { // 使用Executors框架生成ThreadPool ExecutorService executorService=Executors.newFixedThreadPool(4); for (int i=0; i <10; i++) { // 提交任务 executorService.submit(new Runnable() { @Override public void run() { System.out.println(in); } }); } }}

ExecutorService的使用

public class ThreadPoolDemo { public static void main(String[] args) { /* * 使用Executors框架生成ThreadPool */ ExecutorService executorService = Executors.newFixedThreadPool(4); for (int i = 0; i < 10; i++) { int index = i; executorService.submit(() -> System.out.println("i:" + index + " executorServiceByExecutors")); } executorService.shutdown(); } } ThreadPoolExecutor的使用

public class ThreadPoolDemo { public static void main(String[] args) { /* * 自定义的ThreadPoolExecutor，但是使用的是默认的形式 * int corePoolSize, * int maximumPoolSize, * long keepAliveTime, * TimeUnit unit, * BlockingQueue workQueue, * ThreadFactory threadFactory, * RejectedExecutionHandler handler */ ThreadPoolExecutor pool = new ThreadPoolExecutor(2, 2, 0L, TimeUnit.MILLISECONDS, new LinkedBlockingQueue<>(10), Executors.defaultThreadFactory(), new ThreadPoolExecutor.AbortPolicy()); for (int i = 0; i < 10; i++) { int index = i; pool.submit(() -> System.out.println("i:" + index + " executorService")); } pool.shutdown(); } } ExecutorService和ThreadPoolExecutor的使用

public class ThreadPoolDemo { public static void main(String[] args) { ExecutorService executorService = new ThreadPoolExecutor(2, 2, 0L, TimeUnit.MILLISECONDS, new LinkedBlockingQueue<>(10), Executors.defaultThreadFactory(), new ThreadPoolExecutor.AbortPolicy()); for (int i = 0; i < 10; i++) { int index = i; executorService.submit(() -> System.out.println("i:" + index + "executorService")); } executorService.shutdown(); } } 自定义ThreadFactory、拒绝策略以及重写ThreadPoolExecutor的beforeExecute、afterExecute、terminated方法

public class ThreadPoolDemo2 { public static void main(String[] args) { ExecutorService executorService = new ThreadPoolExecutor(2, 2, 0L, TimeUnit.MILLISECONDS, new LinkedBlockingQueue<>(), r -> { Thread thread = new Thread(r); thread.setName(r.getClass().getName()); return thread; }, new ThreadPoolExecutor.AbortPolicy()) { @Override protected void beforeExecute(Thread t, Runnable r) { super.beforeExecute(t, r); System.out.println("beforeExecute"); } @Override protected void afterExecute(Runnable r, Throwable t) { super.afterExecute(r, t); System.out.println("afterExecute"); } @Override protected void terminated() { super.terminated(); System.out.println("terminated"); } }; for (int i = 0; i < 10; i++) { int index = i; /* *如果直接使用 submit进行提交的话，如果县城中运行的有错误的话，就不会显示出来堆栈信息 */ executorService.submit(() -> System.out.println("i:" + index)); } executorService.shutdown(); } } submit和future的区别

/** * 错误信息如果使用submit则无法显示，一种方式是放弃使用submit，另一种是可以使用execute */ public class ThreadPoolDemo3 { public static void main(String[] args) { ThreadPoolExecutor pool = new ThreadPoolExecutor(2, 2, 0L, TimeUnit.SECONDS, new LinkedBlockingQueue<>(10), Executors.defaultThreadFactory()); for (int i = 0; i < 5; i++) { int index = i; pool.submit(() -> divTask(100, index)); Future future = pool.submit(() -> divTask(100, index)); try { future.get(); } catch (InterruptedException | ExecutionException e) { e.printStackTrace(); } } pool.shutdown(); } private static void divTask(int a, int b) { double result = a / b; System.out.println(result); } } 如何打印错误的堆栈信息

/** * 直接使用ExecutorService pool = Executors.newFixedThreadPool(2); pool.submit()也不会出现错误的堆栈信息 * 错误信息如果使用submit则无法显示，一种方式是放弃使用submit，另一种是可以使用execute */ public class ThreadPoolDemo4 { public static void main(String[] args) { ExecutorService pool = Executors.newFixedThreadPool(2); for (int i = 0; i < 5; i++) { int index = i; /* * 不会出现错误的堆栈信息 */ pool.submit(() -> divTask(100, index)); //1、可以使用Future future = pool.submit();实现错误信息堆栈信息 Future future = pool.submit(() -> divTask(100, index)); try { future.get(); } catch (InterruptedException | ExecutionException e) { e.printStackTrace(); } //2、可以使用pool.execute();实现错误信息堆栈信息 pool.execute(() -> divTask(100, index)); } pool.shutdown(); } private static void divTask(int a, int b) { double result = a / b; System.out.println(result); } } 自定义继承ThreadPoolExecutor

public class TraceThreadPoolExecutor extends ThreadPoolExecutor { public TraceThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue workQueue) { super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue); } @Override public Future submit(Runnable task) { return super.submit(wrap(task, clientTrace(), Thread.currentThread().getName())); } private Runnable wrap(Runnable task, Exception clientTrace, String currentThreadName) { return () -> { try { task.run(); } catch (Exception e) { clientTrace.printStackTrace(); throw e; } }; } private Exception clientTrace() { return new Exception("Client stack trace"); } public static void main(String[] args) { ThreadPoolExecutor pool = new TraceThreadPoolExecutor(0, Integer.MAX_VALUE, 0L, TimeUnit.SECONDS, new SynchronousQueue<>()); for (int i = 0; i < 5; i++) { int index = i; pool.execute(() -> divTask(100, index)); } } private static void divTask(int a, int b) { double result = a / b; System.out.println(result); } }