ScheduledThreadPool线程调度 ScheduledThreadPool线程调度package com.yanxizhu; import java.util.Random; import java.util.concurrent.Callable; import java.util.concurrent.Executors; import java.util.concurrent.Future; import java.util.concurrent.ScheduledExecutorService; import java.util.concurrent.TimeUnit; /* * 一、线程池：提供了一个线程队列，队列中保存着所有等待状态的线程。避免了创建与销毁额外开销，提高了响应的速度。 * * 二、线程池的体系结构： * java.util.concurrent.Executor : 负责线程的使用与调度的根接口 * |--**ExecutorService 子接口: 线程池的主要接口 * |--ThreadPoolExecutor 线程池的实现类 * |--ScheduledExecutorService 子接口：负责线程的调度 * |--ScheduledThreadPoolExecutor ：继承 ThreadPoolExecutor， 实现 ScheduledExecutorService * * 三、工具类 : Executors * ExecutorService newFixedThreadPool() : 创建固定大小的线程池 * ExecutorService newCachedThreadPool() : 缓存线程池，线程池的数量不固定，可以根据需求自动的更改数量。 * ExecutorService newSingleThreadExecutor() : 创建单个线程池。线程池中只有一个线程 * * ScheduledExecutorService newScheduledThreadPool() : 创建固定大小的线程，可以延迟或定时的执行任务。 */ public class TestScheduledThreadPool { public static void main(String[] args) throws Exception { ScheduledExecutorService pool = Executors.newScheduledThreadPool(5); for (int i = 0; i < 5; i++) { Future<Integer> result = pool.schedule(new Callable<Integer>(){ @Override public Integer call() throws Exception { int num = new Random().nextInt(100);//生成随机数 System.out.println(Thread.currentThread().getName() + " : " + num); return num; } }, 1, TimeUnit.SECONDS); System.out.println(result.get()); } pool.shutdown(); } }

Executor线程池 Executors线程池package com.yanxizhu; import java.util.ArrayList; import java.util.List; import java.util.concurrent.Callable; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.Future; /* * 一、线程池：提供了一个线程队列，队列中保存着所有等待状态的线程。避免了创建与销毁额外开销，提高了响应的速度。 * * 二、线程池的体系结构： * java.util.concurrent.Executor : 负责线程的使用与调度的根接口 * |--**ExecutorService 子接口: 线程池的主要接口 * |--ThreadPoolExecutor 线程池的实现类 * |--ScheduledExecutorService 子接口：负责线程的调度 * |--ScheduledThreadPoolExecutor ：继承 ThreadPoolExecutor， 实现 ScheduledExecutorService * * 三、工具类 : Executors * ExecutorService newFixedThreadPool() : 创建固定大小的线程池 * ExecutorService newCachedThreadPool() : 缓存线程池，线程池的数量不固定，可以根据需求自动的更改数量。 * ExecutorService newSingleThreadExecutor() : 创建单个线程池。线程池中只有一个线程 * * ScheduledExecutorService newScheduledThreadPool() : 创建固定大小的线程，可以延迟或定时的执行任务。 */ public class TestThreadPool { public static void main(String[] args) throws Exception { //1. 创建线程池 ExecutorService pool = Executors.newFixedThreadPool(5); List<Future<Integer>> list = new ArrayList<>(); for (int i = 0; i < 10; i++) { Future<Integer> future = pool.submit(new Callable<Integer>(){ @Override public Integer call() throws Exception { int sum = 0; for (int i = 0; i <= 100; i++) { sum += i; } return sum; } }); list.add(future); } pool.shutdown(); for (Future<Integer> future : list) { System.out.println(future.get()); } /*ThreadPoolDemo tpd = new ThreadPoolDemo(); //2. 为线程池中的线程分配任务 for (int i = 0; i < 10; i++) { pool.submit(tpd); } //3. 关闭线程池 pool.shutdown();*/ } // new Thread(tpd).start(); // new Thread(tpd).start(); } class ThreadPoolDemo implements Runnable{ private int i = 0; @Override public void run() { while(i <= 100){ System.out.println(Thread.currentThread().getName() + " : " + i++); } } }

ReadWriteLock读写锁 读写锁package com.yanxizhu; import java.util.concurrent.locks.ReadWriteLock; import java.util.concurrent.locks.ReentrantReadWriteLock; /** * @description: 读写锁(互斥锁) * @author: <a href="mailto:batis@foxmail.com">清风</a> * @date: 2022/3/19 15:23 * @version: 1.0 */ public class ReadWriteDemo { public static void main(String[] args) { ReadWriteTest readWriteTest = new ReadWriteTest(); new Thread(()->{ readWriteTest.write((int) (Math.random()*101)); },"写锁").start(); for(int i=1;i<50;i++){ new Thread(()->{ readWriteTest.get(); },"读锁").start(); } } } class ReadWriteTest{ int num =0; private ReadWriteLock readWriteLock = new ReentrantReadWriteLock(); //读 public void get(){ readWriteLock.readLock().lock(); try{ System.out.println(num+"=="+Thread.currentThread().getName()); }finally { readWriteLock.readLock().unlock(); } } //写 public void write(int i){ readWriteLock.writeLock().lock(); try{ this.num=i; }finally { readWriteLock.writeLock().unlock(); } } }

线程按序交替 线程按序交替package com.yanxizhu; import java.util.concurrent.locks.Condition; import java.util.concurrent.locks.Lock; import java.util.concurrent.locks.ReentrantLock; /** * @description: 线程按序交替 * @date: 2022/3/19 14:47 * @version: 1.0 */ public class PrintInfo { public static void main(String[] args) { print print = new print(); new Thread(new Runnable() { @Override public void run() { for(int i=1;i<5;i++){ try { print.printA(i); } catch (InterruptedException e) { e.printStackTrace(); } } } },"A").start(); new Thread(new Runnable() { @Override public void run() { for(int i=1;i<5;i++){ try { print.printB(i); } catch (InterruptedException e) { e.printStackTrace(); } } } },"B").start(); new Thread(new Runnable() { @Override public void run() { for(int i=1;i<5;i++){ try { print.printC(i); } catch (InterruptedException e) { e.printStackTrace(); } } } },"C").start(); } } class print{ private int num =1; Lock lock = new ReentrantLock(); Condition condition1 = lock.newCondition(); Condition condition2 = lock.newCondition(); Condition condition3 = lock.newCondition(); public void printA(int i) throws InterruptedException { lock.lock(); try{ if(num != 1){ condition1.await(); } System.out.println("A=="+Thread.currentThread().getName()+"====i="+i); num=2; condition2.signal(); }finally { lock.unlock(); } } public void printB(int i) throws InterruptedException { lock.lock(); try{ if(num != 2){ condition2.await(); } System.out.println("B=="+Thread.currentThread().getName()+"====i="+i); num=3; condition3.signal(); }finally { lock.unlock(); } } public void printC(int i) throws InterruptedException { lock.lock(); try{ if(num != 3){ condition3.await(); } System.out.println("C=="+Thread.currentThread().getName()+"====i="+i); num=1; condition1.signal(); }finally { lock.unlock(); } } }打印结果：A==A====i=1 B==B====i=1 C==C====i=1 A==A====i=2 B==B====i=2 C==C====i=2 A==A====i=3 B==B====i=3 C==C====i=3 A==A====i=4 B==B====i=4 C==C====i=4

wait、notifyAll()、await()、signalAll() wait、notifyAll()、await()、signalAll()为了避免虚假唤醒问题，应该总是使用在循环中wait、notifyAll():package com.yanxizhu; import java.util.function.Consumer; /* * 生产者和消费者案例 */ public class TestProductorAndConsumer { public static void main(String[] args) { Clerk clerk = new Clerk(); Productor pro = new Productor(clerk); Consumers cus = new Consumers(clerk); new Thread(pro, "生产者 A").start(); new Thread(cus, "消费者 B").start(); new Thread(pro, "生产者 C").start(); new Thread(cus, "消费者 D").start(); } } //店员 class Clerk{ private int product = 0; //进货 public synchronized void get(){//循环次数：0 while(product >= 1){//为了避免虚假唤醒问题，应该总是使用在循环中 System.out.println("产品已满！"); try { this.wait(); } catch (InterruptedException e) { } } System.out.println(Thread.currentThread().getName() + " : " + ++product); this.notifyAll(); } //卖货 public synchronized void sale(){//product = 0; 循环次数：0 while(product <= 0){ System.out.println("缺货！"); try { this.wait(); } catch (InterruptedException e) { } } System.out.println(Thread.currentThread().getName() + " : " + --product); this.notifyAll(); } } //生产者 class Productor implements Runnable{ private Clerk clerk; public Productor(Clerk clerk) { this.clerk = clerk; } @Override public void run() { for (int i = 0; i < 20; i++) { try { Thread.sleep(200); } catch (InterruptedException e) { } clerk.get(); } } } //消费者 class Consumers implements Runnable{ private Clerk clerk; public Consumers(Clerk clerk) { this.clerk = clerk; } @Override public void run() { for (int i = 0; i < 20; i++) { clerk.sale(); } } }await()、signalAll()package com.yanxizhu; import java.util.concurrent.locks.Condition; import java.util.concurrent.locks.Lock; import java.util.concurrent.locks.ReentrantLock; /* * 生产者消费者案例： */ public class TestProductorAndConsumerForLock { public static void main(String[] args) { Clerk clerk = new Clerk(); Productor pro = new Productor(clerk); Consumer con = new Consumer(clerk); new Thread(pro, "生产者 A").start(); new Thread(con, "消费者 B").start(); // new Thread(pro, "生产者 C").start(); // new Thread(con, "消费者 D").start(); } } class Clerk { private int product = 0; private Lock lock = new ReentrantLock(); private Condition condition = lock.newCondition(); // 进货 public void get() { lock.lock(); try { if (product >= 1) { // 为了避免虚假唤醒，应该总是使用在循环中。 System.out.println("产品已满！"); try { condition.await(); } catch (InterruptedException e) { } } System.out.println(Thread.currentThread().getName() + " : " + ++product); condition.signalAll(); } finally { lock.unlock(); } } // 卖货 public void sale() { lock.lock(); try { if (product <= 0) { System.out.println("缺货！"); try { condition.await(); } catch (InterruptedException e) { } } System.out.println(Thread.currentThread().getName() + " : " + --product); condition.signalAll(); } finally { lock.unlock(); } } } // 生产者 class Productor implements Runnable { private Clerk clerk; public Productor(Clerk clerk) { this.clerk = clerk; } @Override public void run() { for (int i = 0; i < 20; i++) { try { Thread.sleep(200); } catch (InterruptedException e) { e.printStackTrace(); } clerk.get(); } } } // 消费者 class Consumer implements Runnable { private Clerk clerk; public Consumer(Clerk clerk) { this.clerk = clerk; } @Override public void run() { for (int i = 0; i < 20; i++) { clerk.sale(); } } }

ReentrantLock显示锁 package com.yanxizhu; import java.util.concurrent.locks.Lock; import java.util.concurrent.locks.ReentrantLock; /** * @description: ReentrantLock * @author: <a href="mailto:batis@foxmail.com">清风</a> * @date: 2022/3/19 12:37 * @version: 1.0 */ public class LockDemo { public static void main(String[] args) { titck titck = new titck(); new Thread(titck,"线程1").start(); new Thread(titck,"线程2").start(); new Thread(titck,"线程3").start(); } public static class titck implements Runnable{ Lock lock = new ReentrantLock(); private int titck = 100; @Override public void run() { while(true){ lock.lock(); try{ if(titck>0){ try { Thread.sleep(200); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println("剩余票数："+--titck); } }finally { lock.unlock(); } } } } } synchronized:隐式锁1、同步代码块2、同步方法jdk1.5之后：显示锁3、同步锁Lock注意：是一个显示锁，需要通过lock()方法上锁，必须通过unlock()方法进行释放锁。