/** * 1.创建一个可缓存线程池,如果线程池长度超过处理需要,可灵活回收空闲线程,若无可回收,则新建线程 */ public static void cachedThreadPool() { ExecutorService cachedThreadPool = Executors.newCachedThreadPool(); for (int i = 0; i < 10; i++) { final int index = i; try { Thread.sleep(1 * 1000); } catch (InterruptedException e) { e.printStackTrace(); } cachedThreadPool.execute(new Runnable() { @Override public void run() { System.out.println(index + "--" + Thread.currentThread().getId()); } }); } } /** * 2.创建一个定长线程池,可控制线程最大并发数,超出的线程会在队列中等待 */ public static void newFixedThreadPool() { ExecutorService fixedThreadPool = Executors.newFixedThreadPool(5); for (int i = 0; i < 10; i++) { final int index = i; fixedThreadPool.execute(new Runnable() { @Override public void run() { try { System.out.println(index + "-----" + Thread.currentThread().getId()); Thread.sleep(2000); } catch (InterruptedException e) { e.printStackTrace(); } } }); } //fixedThreadPool.shutdown(); } /** * 3.创建一个定长线程池,支持定时及周期性任务执行 */ public static void newScheduledThreadPool() { ScheduledExecutorService scheduledThreadPool = Executors.newScheduledThreadPool(5); Calendar calendar = Calendar.getInstance(); calendar.set(Calendar.HOUR_OF_DAY, 10); // 时 calendar.set(Calendar.MINUTE, 53);// 分 calendar.set(Calendar.SECOND, 00); // 秒 //计算现在时间和计划任务执行时间差多久,单位毫秒 Long date = calendar.getTime().getTime() - System.currentTimeMillis(); // //延迟3秒执行 scheduledThreadPool.schedule(new Runnable() { @Override public void run() { System.out.println("delay 3 seconds--" + new Date().toLocaleString()); } }, 3, TimeUnit.SECONDS); //延迟5秒执行,然后每隔2秒执行一次 scheduledThreadPool.scheduleAtFixedRate(new Runnable() { @Override public void run() { System.out.println("延迟5秒执行,然后每隔2秒执行一次--" + new Date().toLocaleString()); } }, 5, 2, TimeUnit.SECONDS); //定时在某一时刻执行任务,然后间隔执行,如果时间过了会立马执行 scheduledThreadPool.scheduleAtFixedRate(new Runnable() { @Override public void run() { System.out.println("定时在某一时刻执行任务,然后间隔执行--" + new Date().toLocaleString()); } }, date / 1000, 2, TimeUnit.SECONDS); } /** *4. 创建一个单线程化的线程池,它只会用唯一的工作线程来执行任务, * 保证所有任务按照指定顺序(FIFO, LIFO, 优先级)执行 */ public static void newSingleThreadExecutor() { ExecutorService singleThreadExecutor = Executors.newSingleThreadExecutor(); for (int i = 0; i < 10; i++) { final int index = i; singleThreadExecutor.execute(new Runnable() { @Override public void run() { try { System.out.println("单线程执行任务。。。"); Thread.sleep(2000); } catch (InterruptedException e) { e.printStackTrace(); } } }); } }