整站优化价格,设计上海展会2023,网站开发开题报告,在线做图软件文章目录 学习链接CountDownLatchCountDownLatch类的作用类的主要方法介绍图解await和countDown方法两个典型用法注意点总结示例CountDownLatchDemo1CountDownLatchDemo2CountDownLatchDemo1And2 CyclicBarrierCyclicBarrier循环栅栏CyclicBarrier和CountDownLatch的区别示例Cy… 文章目录 学习链接CountDownLatchCountDownLatch类的作用类的主要方法介绍图解await和countDown方法两个典型用法注意点总结示例CountDownLatchDemo1CountDownLatchDemo2CountDownLatchDemo1And2 CyclicBarrierCyclicBarrier循环栅栏CyclicBarrier和CountDownLatch的区别示例CyclicBarrierDemo SemaphoreSemaphore信号量Semaphore应用实例信号量的使用流程信号量主要方法介绍信号量的特殊用法注意点示例SemaphoreDemo ConditionCondition的作用signalAll和signal的区别Condition注意点示例Condition1Condition2 学习链接
Java并发编程第9讲——CountDownLatch、CyclicBarrier和Semaphore万字详解
CountDownLatch
CountDownLatch类的作用 类的主要方法介绍 图解await和countDown方法 两个典型用法 注意点 总结 示例
CountDownLatchDemo1
/*** 描述工厂中质检5个工人检查所有人都认为通过才通过*/
public class CountDownLatchDemo1 {public static void main(String[] args) throws InterruptedException {CountDownLatch latch new CountDownLatch(5);ExecutorService service Executors.newFixedThreadPool(5);for (int i 0; i 5; i) {final int no i 1;Runnable runnable new Runnable() {Overridepublic void run() {try {Thread.sleep((long) (Math.random() * 10000));System.out.println(No. no 完成了检查。);} catch (InterruptedException e) {e.printStackTrace();} finally {latch.countDown();}}};service.submit(runnable);}System.out.println(等待5个人检查完.....);latch.await(); // 这里也可以设置超时等待时间, 如: latch.await(5, TimeUnit.SECONDS);System.out.println(所有人都完成了工作进入下一个环节。);}
}
CountDownLatchDemo2
/*** 描述模拟100米跑步5名选手都准备好了只等裁判员一声令下所有人同时开始跑步。*/
public class CountDownLatchDemo2 {public static void main(String[] args) throws InterruptedException {CountDownLatch begin new CountDownLatch(1);ExecutorService service Executors.newFixedThreadPool(5);for (int i 0; i 5; i) {final int no i 1;Runnable runnable new Runnable() {Overridepublic void run() {System.out.println(No. no 准备完毕等待发令枪);try {begin.await();System.out.println(No. no 开始跑步了);} catch (InterruptedException e) {e.printStackTrace();}}};service.submit(runnable);}//裁判员检查发令枪...Thread.sleep(5000);System.out.println(发令枪响比赛开始);begin.countDown();}
}CountDownLatchDemo1And2
/*** 描述模拟100米跑步5名选手都准备好了只等裁判员一声令下所有人同时开始跑步。当所有人都到终点后比赛结束。*/
public class CountDownLatchDemo1And2 {public static void main(String[] args) throws InterruptedException {CountDownLatch begin new CountDownLatch(1);CountDownLatch end new CountDownLatch(5);ExecutorService service Executors.newFixedThreadPool(5);for (int i 0; i 5; i) {final int no i 1;Runnable runnable new Runnable() {Overridepublic void run() {System.out.println(No. no 准备完毕等待发令枪);try {begin.await();System.out.println(No. no 开始跑步了);Thread.sleep((long) (Math.random() * 10000));System.out.println(No. no 跑到终点了);} catch (InterruptedException e) {e.printStackTrace();} finally {end.countDown();}}};service.submit(runnable);}//裁判员检查发令枪...Thread.sleep(5000);System.out.println(发令枪响比赛开始);begin.countDown();end.await();System.out.println(所有人到达终点比赛结束);}
}
CyclicBarrier
CyclicBarrier循环栅栏 CyclicBarrier和CountDownLatch的区别 示例
CyclicBarrierDemo
/*** 描述 演示CyclicBarrier*/
public class CyclicBarrierDemo {public static void main(String[] args) {// 5个线程都调用await时才执行Runnable然后5个线程接着执行CyclicBarrier cyclicBarrier new CyclicBarrier(5, new Runnable() {Overridepublic void run() {System.out.println(所有人都到场了 大家统一出发);}});// 这里循环10次目的是验证CyclicBarrier可重用for (int i 0; i 10; i) {new Thread(new Task(i, cyclicBarrier)).start();}}static class Task implements Runnable {private int id;private CyclicBarrier cyclicBarrier;public Task(int id, CyclicBarrier cyclicBarrier) {this.id id;this.cyclicBarrier cyclicBarrier;}Overridepublic void run() {System.out.println(线程 id 现在前往集合地点);try {Thread.sleep((long) (Math.random() * 10000));System.out.println(线程 id 到了集合地点开始等待其他人到达);cyclicBarrier.await();System.out.println(线程 id 出发了);} catch (InterruptedException e) {e.printStackTrace();} catch (BrokenBarrierException e) {e.printStackTrace();}}}
}
Semaphore
Semaphore信号量 Semaphore应用实例 信号量的使用流程 信号量主要方法介绍 信号量的特殊用法 注意点 示例
SemaphoreDemo
/*** 描述 演示Semaphore用法*/
public class SemaphoreDemo {static Semaphore semaphore new Semaphore(3, true);public static void main(String[] args) {ExecutorService service Executors.newFixedThreadPool(50);for (int i 0; i 100; i) {service.submit(new Task());}service.shutdown();}static class Task implements Runnable {Overridepublic void run() {try {semaphore.acquire(1);} catch (InterruptedException e) {e.printStackTrace();}System.out.println(Thread.currentThread().getName() 拿到了许可证);try {Thread.sleep(2000);} catch (InterruptedException e) {e.printStackTrace();}System.out.println(Thread.currentThread().getName() 释放了许可证);semaphore.release(1);}}
}Condition
Condition的作用 signalAll和signal的区别 Condition注意点 示例
Condition1
/*** 描述演示Condition的基本用法*/
public class ConditionDemo1 {private ReentrantLock lock new ReentrantLock();private Condition condition lock.newCondition();void method1() throws InterruptedException {lock.lock();try{System.out.println(条件不满足开始await);condition.await(); // 可设置超时时间进入条件等待: condition.await(1, TimeUnit.SECONDS);System.out.println(条件满足了开始执行后续的任务);}finally {lock.unlock();}}void method2() {lock.lock();try{System.out.println(准备工作完成唤醒其他的线程);condition.signal();}finally {lock.unlock();}}public static void main(String[] args) throws InterruptedException {ConditionDemo1 conditionDemo1 new ConditionDemo1();new Thread(new Runnable() {Overridepublic void run() {try {Thread.sleep(1000);conditionDemo1.method2();} catch (InterruptedException e) {e.printStackTrace();}}}).start();conditionDemo1.method1();}
}Condition2
/*** 描述 演示用Condition实现生产者消费者模式*/
public class ConditionDemo2 {private int queueSize 10;private PriorityQueueInteger queue new PriorityQueueInteger(queueSize);private Lock lock new ReentrantLock();// 当队列不满足 不满的条件时生产者进入等待// 当队列不满时唤醒在此条件中等待的线程private Condition notFull lock.newCondition();// 当队列不满足 不空的条件时消费者进入等待// 当队列不空时唤醒在此条件中等待的线程private Condition notEmpty lock.newCondition();public static void main(String[] args) {ConditionDemo2 conditionDemo2 new ConditionDemo2();Producer producer conditionDemo2.new Producer();Consumer consumer conditionDemo2.new Consumer();producer.start();consumer.start();}class Consumer extends Thread {Overridepublic void run() {consume();}private void consume() {while (true) {lock.lock();try {// 使用while, 防止了虚假唤醒while (queue.size() 0) {System.out.println(队列空等待数据);try {// 当队列为空时进入等待// 当队列不为空时被唤醒notEmpty.await(); // 进入条件队列中等待并释放锁此处被唤醒时仍然需要获取到锁才能往下运行} catch (InterruptedException e) {e.printStackTrace();}}// 走到这里说明队列肯定不为空了// 因为先持有了锁, 所以保证了操作的原子性。其它此时尝试从该队列中获取数据的线程将进入锁等待环节queue.poll();// 因为拿到了锁, 并且从队列中获取了数据, 队列此时肯定不为满了, 所以可以唤醒生产者线程去生产notFull.signalAll();System.out.println(从队列里取走了一个数据队列剩余 queue.size() 个元素);} finally {lock.unlock();}}}}class Producer extends Thread {Overridepublic void run() {produce();}private void produce() {while (true) {lock.lock();try {// 使用while, 防止了虚假唤醒while (queue.size() queueSize) {System.out.println(队列满等待有空余);try {// 当队列为满时进入等待// 当队列为不满时被唤醒notFull.await(); // 进入条件队列中等待并释放锁此处被唤醒时仍然需要获取到锁才能往下运行} catch (InterruptedException e) {e.printStackTrace();}}// 走到这里说明队列肯定不为满了// 因为先持有了锁, 所以保证了操作的原子性。其它此时尝试往该队列中添加数据的线程将进入锁等待环节queue.offer(1);// 因为拿到了锁, 并且往该队列中添加了数据, 队列此时肯定不为空了, 所以可以唤醒消费者者线程去消费notEmpty.signalAll();System.out.println(向队列插入了一个元素队列剩余空间 (queueSize - queue.size()));} finally {lock.unlock();}}}}}
