Java-五种线程池，四种拒绝策略，三种阻塞队列
三种阻塞队列： BlockingQueue<Runnable> workQueue = null; workQueue = new ArrayBlockingQueue<>(5);//基于数组的先进先出队列，有界 workQueue = new LinkedBlockingQueue<>();//基于链表的先进先出队列，无界 workQueue = new SynchronousQueue<>();//无缓冲的等待队列，无界 四种拒绝策略： RejectedExecutionHandler rejected = null; rejected = new ThreadPoolExecutor.AbortPolicy();//默认，队列满了丢任务抛出异常 rejected = new ThreadPoolExecutor.DiscardPolicy();//队列满了丢任务不异常 rejected = new ThreadPoolExecutor.DiscardOldestPolicy();//将最早进入队列的任务删，之后再尝试加入队列 rejected = new ThreadPoolExecutor.CallerRunsPolicy();//如果添加到线程池失败，那么主线程会自己去执行该任务 五种线程池： ExecutorService threadPool = null; threadPool = Executors.newCachedThreadPool();//有缓冲的线程池，线程数 JVM 控制 threadPool = Executors.newFixedThreadPool(3);//固定大小的线程池 threadPool = Executors.newScheduledThreadPool(2); threadPool = Executors.newSingleThreadExecutor();//单线程的线程池，只有一个线程在工作 threadPool = new ThreadPoolExecutor();//默认线程池，可控制参数比较多
public static void main (String[] args) throws Exception { testThreadPoolExecutor(); } public static void testThreadPoolExecutor() throws Exception { //基础参数 int corePoolSize=2;//最小活跃线程数 int maximumPoolSize=5;//最大活跃线程数 int keepAliveTime=5;//指定线程池中线程空闲超过 5s 后将被回收 TimeUnit unit = TimeUnit.SECONDS;//keepAliveTime 单位 //阻塞队列 BlockingQueue<Runnable> workQueue = null; workQueue = new ArrayBlockingQueue<>(5);//基于数组的先进先出队列，有界 workQueue = new LinkedBlockingQueue<>();//基于链表的先进先出队列，无界 workQueue = new SynchronousQueue<>();//无缓冲的等待队列，无界 //拒绝策略 RejectedExecutionHandler rejected = null; rejected = new ThreadPoolExecutor.AbortPolicy();//默认，队列满了丢任务抛出异常 rejected = new ThreadPoolExecutor.DiscardPolicy();//队列满了丢任务不异常 rejected = new ThreadPoolExecutor.DiscardOldestPolicy();//将最早进入队列的任务删，之后再尝试加入队列 rejected = new ThreadPoolExecutor.CallerRunsPolicy();//如果添加到线程池失败，那么主线程会自己去执行该任务 //使用的线程池 ExecutorService threadPool = null; threadPool = Executors.newCachedThreadPool();//有缓冲的线程池，线程数 JVM 控制 threadPool = Executors.newFixedThreadPool(3);//固定大小的线程池 threadPool = Executors.newScheduledThreadPool(2); threadPool = Executors.newSingleThreadExecutor();//单线程的线程池，只有一个线程在工作 threadPool = new ThreadPoolExecutor( corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, rejected);//默认线程池，可控制参数比较多 //执行无返回值线程 TaskRunnable taskRunnable = new TaskRunnable(); threadPool.execute(taskRunnable); List<Future<String>> futres = new ArrayList<>(); for(int i=0;i<10;i++) { //执行有返回值线程 TaskCallable taskCallable = new TaskCallable(i); Future<String> future = threadPool.submit(taskCallable); futres.add(future); } for(int i=0;i<futres.size();i++){ String result = futres.get(i).get(); System.out.println(i+" result = "+result); } } /** * 返回值的线程，使用 threadpool.execut() 执行 */ public static class TaskRunnable implements Runnable{ @Override public void run() { try { Thread.sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println(Thread.currentThread().getName() + " runnable result!"); } } /** * 有返回值的线程，使用 threadpool.submit() 执行 */ public static class TaskCallable implements Callable<String>{ public TaskCallable(int index){ this.i=index; } private int i; @Override public String call() throws Exception { int r = new Random().nextInt(5); try { Thread.sleep(r); } catch (InterruptedException e) { e.printStackTrace(); } //System.out.println("callable result!"); return Thread.currentThread().getName()+" callable index="+i +",sleep="+r; } } ———————————————— 版权声明：本文为博主「草青工作室」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。 原文链接：https://blog.csdn.net/xxj_jing/article/details/84835476
