一、并发设计模式

 什么是设计模式
 单例模式
 不变模式
 Future模式
 生产者消费者
  1. 什么是设计模式

     在软件工程中,设计模式(design pattern)是对软件设计中普遍存在(反复出现)的各种问题 ,所提出的解决方案。这个术语是由埃里希·伽玛(Erich Gamma)等人在1990年代从建筑设计领 域引入到计算机科学的。
      Richard Helm, Ralph Johnson ,John Vlissides (Gof)
      《设计模式:可复用面向对象软件的基础》 收录 23种模式
    
      – 观察者模式
      – 策略模式
      – 装饰者模式 – 享元模式
      – 模板方法
    
      架构模式 – MVC
     – 分层
      设计模式
     – 提炼系统中的组件
      代码模式(成例 Idiom)
     – 低层次,与编码直接相关 – 如DCL
    
  2. 单例模式

     单例对象的类必须保证只有一个实例存在。许多时候整个系统只需要拥有一个的全局对象,这样 有利于我们协调系统整体的行为
     比如:全局信息配置
    
    	/**
    	 * description: 饿汉式 线程安全
    	 *
    	 * @author: dawn.he QQ:       905845006
    	 * @email: [email protected]
    	 * @email: [email protected]
    	 * @date: 2019/10/4    7:32 PM
    	 */
    	public class Singleton {
    		public static int STATUS = 1;
    
    		private Singleton() {
    			System.out.println("Singleton is create");
    		}
    
    		private static Singleton instance = new Singleton();
    
    		public static Singleton getInstance() {
    			return instance;
    		}
    
    		public static void main(String[] args) {
    			//何时产生实例 不好控制
    			System.out.println(Singleton.STATUS);
    			//输出
    			// Singleton is create
    			//1
    		}
    
    
    	}
    
    	/**
    	 * description: 懒汉式 线程安全
    	 *
    	 * @author: dawn.he QQ:       905845006
    	 * @email: [email protected]
    	 * @email: [email protected]
    	 * @date: 2019/10/4    7:37 PM
    	 */
    	public class LazySingleton {
    		//1.
    		private LazySingleton() {
    			System.out.println("LazySingleton is create");
    		}
    
    		private static LazySingleton instance = null;
    
    		public static synchronized LazySingleton getInstance() {
    			if (instance == null)
    				instance = new LazySingleton();
    			return instance;
    
    		}
    
    	//      2. 多线程 性能好
    	//    双检锁/双重校验锁(DCL,即 double-checked locking)线程安全
    	//    private volatile static LazySingleton instance;
    	//    private LazySingleton (){
    	//        System.out.println("LazySingleton is create");
    	//    }
    	//    public static LazySingleton getInstance() {
    	//        if (instance == null) {
    	//            synchronized (LazySingleton.class) {
    	//                if (instance == null) {
    	//                    instance = new LazySingleton();
    	//                }
    	//            }
    	//        }
    	//        return instance;
    	//    }
    
    		public static void main(String[] args) {
    			LazySingleton.getInstance();
    		}
    	}
    
    	/**
    	 * description: 静态内部类 线程安全
    	 *
    	 * @author: dawn.he QQ:       905845006
    	 * @email: [email protected]
    	 * @email: [email protected]
    	 * @date: 2019/10/4    7:39 PM
    	 */
    	public class StaticSingleton {
    		private StaticSingleton() {
    			System.out.println("StaticSingleton is create");
    		}
    
    		private static class SingletonHolder {
    			private static final StaticSingleton instance = new StaticSingleton();
    		}
    
    		public static final StaticSingleton getInstance() {
    			return SingletonHolder.instance;
    		}
    
    
    		public static void main(String[] args) {
    			StaticSingleton.getInstance();
    		}
    	}
    
  3. 不变模式

      一个类的内部状态创建后,在整个生命期间都不会发生变化时,就是不变类
      不变模式不需要同步
    
    	/**
    	 * description:
    	 *
    	 * @author: dawn.he QQ:       905845006
    	 * @email: [email protected]
    	 * @email: [email protected]
    	 * @date: 2019/10/4    7:55 PM
    	 */
    	//确保无子类
    	public final class Product {
    		private final String no;
    		//私有属性,不会被其他对象获取
    		private final String name;
    		//final保证属性不会被2次赋值
    		private final double price;
    
    		public Product(String no, String name, double price) {
    			super();
    			//因为创建之后,无法进行修改
    			this.no = no;
    			this.name = name;
    			this.price = price;
    		}
    
    		public String getNo() {
    			return no;
    		}
    
    		public String getName() {
    			return name;
    		}
    
    		public double getPrice() {
    			//在创建对象时,必须指定数据
    			return price;
    		}
    
    	}
    
      java.lang.String
      java.lang.Boolean
      java.lang.Byte
      java.lang.Character
      java.lang.Double
      java.lang.Float
      java.lang.Integer
      java.lang.Long
      java.lang.Short
    
  4. Future模式

    02.第二阶段、实战Java高并发程序设计模式-6.并发设计模式-LMLPHP

    02.第二阶段、实战Java高并发程序设计模式-6.并发设计模式-LMLPHP

    	/**
    	 * description:
    	 *
    	 * @author: dawn.he QQ:       905845006
    	 * @email: [email protected]
    	 * @email: [email protected]
    	 * @date: 2019/10/4    8:07 PM
    	 */
    	public class RealData implements Data {
    		protected final String result;
    
    		public RealData(String para) {
    			//RealData的构造可能很慢,需要用户等待很久,这里使用sleep模拟
    			StringBuffer sb = new StringBuffer();
    			for (int i = 0; i < 10; i++) {
    				sb.append(para);
    				try {
    					//这里使用sleep,代替一个很慢的操作过程
    					Thread.sleep(100);
    				} catch (InterruptedException e) {
    				}
    			}
    			result = sb.toString();
    		}
    
    		public String getResult() {
    			return result;
    		}
    	}
    
    	/**
    	 * description:
    	 *
    	 * @author: dawn.he QQ:       905845006
    	 * @email: [email protected]
    	 * @email: [email protected]
    	 * @date: 2019/10/4    8:05 PM
    	 */
    	public class FutureData implements Data {
    		//FutureData是RealData的包装
    
    		protected RealData realdata = null;
    		protected boolean isReady = false;
    
    		public synchronized void setRealData(RealData realdata) {
    			if (isReady) {
    				return;
    			}
    			this.realdata = realdata;
    			isReady = true;
    			//RealData已经被注入,通知getResult()
    			notifyAll();
    		}
    
    		//会等待RealData构造完成
    		public synchronized String getResult() {
    			while (!isReady) {
    				try {
    					//一直等待,知道RealData被注入
    
    					wait();
    				} catch (InterruptedException e) {
    				}
    			}
    			//由RealData实现
    			return realdata.result;
    		}
    	}
    
    	/**
    	 * description:
    	 *
    	 * @author: dawn.he QQ:       905845006
    	 * @email: [email protected]
    	 * @email: [email protected]
    	 * @date: 2019/10/4    8:07 PM
    	 */
    	public class Client {
    		public Data request(final String queryStr) {
    			final FutureData future = new FutureData();
    			new Thread() {
    				// RealData的构建很慢,所以在单独的线程中进行
    				public void run() {
    					RealData realdata = new RealData(queryStr);
    					future.setRealData(realdata);
    				}
    			}.start();
    			// FutureData会被立即返回
    			return future;
    		}
    
    		public static void main(String[] args) {
    
    			Client client = new Client();
    			//这里会立即返回,因为得到的是FutureData而不是RealData
    			Data data = client.request("name");
    			System.out.println("请求完毕");
    			try {
    			//这里可以用一个sleep代替了对其他业务逻辑的处理
    			//在处理这些业务逻辑的过程中,RealData被创建,从而充分利用了等待时间
    				Thread.sleep(2000);
    			} catch (InterruptedException e) {
    			}
    			//使用真实的数据
    			System.out.println("数据 = " + data.getResult());
    		}
    	}
    

    02.第二阶段、实战Java高并发程序设计模式-6.并发设计模式-LMLPHP

    Callable 接口

    	import java.util.concurrent.Callable;
    
    	/**
    	 * description:
    	 *
    	 * @author: dawn.he QQ:       905845006
    	 * @email: [email protected]
    	 * @email: [email protected]
    	 * @date: 2019/10/4    8:07 PM
    	 */
    	public class RealData implements Callable<String> {
    		protected final String para;
    
    		public RealData(String para) {
    
    			this.para = para;
    		}
    
    		@Override
    		public String call() throws Exception {
    			//RealData的构造可能很慢,需要用户等待很久,这里使用sleep模拟
    			StringBuffer sb = new StringBuffer();
    			for (int i = 0; i < 10; i++) {
    				sb.append(para);
    				try {
    					//这里使用sleep,代替一个很慢的操作过程
    					Thread.sleep(100);
    				} catch (InterruptedException e) {
    				}
    			}
    			return sb.toString();
    		}
    	}
    
    	import java.util.concurrent.ExecutionException;
    	import java.util.concurrent.ExecutorService;
    	import java.util.concurrent.Executors;
    	import java.util.concurrent.Future;
    	import java.util.concurrent.FutureTask;
    
    	/**
    	 * description:
    	 *
    	 * @author: dawn.he QQ:       905845006
    	 * @email: [email protected]
    	 * @email: [email protected]
    	 * @date: 2019/10/4    8:27 PM
    	 */
    	public class FutureMain {
    		public static void main(String[] args) throws InterruptedException, ExecutionException {
    			//1.
    	//        //构造FutureTask
    	//        FutureTask<String> future = new FutureTask<String>(new RealData("a"));
    	//        ExecutorService executor = Executors.newFixedThreadPool(1);
    	//        //执行FutureTask,相当于上例中的 client.request("a") 发送请求
    	//        // 在这里开启线程进行RealData的call()执行
    	//        executor.submit(future);
    	//        executor.shutdown();
    	//        System.out.println("请求完毕");
    	//        try {
    	//            //这里依然可以做额外的数据操作,这里使用sleep代替其他业务逻辑的处理
    	//            Thread.sleep(2000);
    	//        } catch (InterruptedException e) {
    	//        }
    	//        //相当于data.getResult (),取得call()方法的返回值
    	//        // 如果此时call()方法没有执行完成,则依然会等待
    	//        System.out.println("数据 = " + future.get());
    
    			//2.
    			ExecutorService executor = Executors.newFixedThreadPool(1);
    			//执行FutureTask,相当于上例中的 client.request("a") 发送请求
    			// 在这里开启线程进行RealData的call()执行
    			Future<String> future = executor.submit(new RealData("a"));
    			System.out.println("请求完毕");
    			try { //这里依然可以做额外的数据操作,这里使用sleep代替其他业务逻辑的处理
    				Thread.sleep(2000);
    			} catch (InterruptedException e) {
    			}
    			//相当于data.getResult (),取得call()方法的返回值
    			// 如果此时call()方法没有执行完成,则依然会等待
    			System.out.println("数据 = " + future.get());
    		}
    
    	}
    
  5. 生产者消费者模式

     生产者-消费者模式是一个经典的多线程设计模式。它为多线程间的协作提供了良好的解决方案。 在生产者-消费者模式中,通常由两类线程,即若干个生产者线程和若干个消费者线程。生产者线 程负责提交用户请求,消费者线程则负责具体处理生产者提交的任务。生产者和消费者之间则通 过共享内存缓冲区进行通信。
    

    02.第二阶段、实战Java高并发程序设计模式-6.并发设计模式-LMLPHP02.第二阶段、实战Java高并发程序设计模式-6.并发设计模式-LMLPHP02.第二阶段、实战Java高并发程序设计模式-6.并发设计模式-LMLPHP

    	/**
    	 * description:
    	 *
    	 * @author: dawn.he QQ:       905845006
    	 * @email: [email protected]
    	 * @email: [email protected]
    	 * @date: 2019/10/4    10:32 PM
    	 */
    	public final class PCData {
    		private final int intData;
    
    		public PCData(int intData) {
    			this.intData = intData;
    		}
    
    		public PCData(String d) {
    			this.intData = Integer.valueOf(d);
    		}
    
    		public int getIntData() {
    			return intData;
    		}
    
    		@Override
    		public String toString() {
    			return "data:" + intData;
    		}
    	}
    
    	import java.util.Random;
    	import java.util.concurrent.BlockingQueue;
    	import java.util.concurrent.TimeUnit;
    	import java.util.concurrent.atomic.AtomicInteger;
    
    	/**
    	 * description:
    	 *
    	 * @author: dawn.he QQ:       905845006
    	 * @email: [email protected]
    	 * @email: [email protected]
    	 * @date: 2019/10/3    10:05 PM
    	 */
    	public class Producer implements Runnable{
    
    		private volatile boolean isRunning = true;
    		private BlockingQueue<PCData> queue;
    		private static AtomicInteger count = new AtomicInteger();
    		private static final int SLEEPTIME = 1000;
    
    		public Producer(BlockingQueue<PCData> queue) {
    			this.queue = queue;
    		}
    
    		@Override
    		public void run() {
    			PCData data = null;
    			Random r = new Random();
    			System.out.println("start producer id=" + Thread.currentThread().getId());
    			try {
    				while (isRunning) {
    					Thread.sleep(r.nextInt(SLEEPTIME));
    					data = new PCData(count.incrementAndGet());
    					System.out.println(data + " is put into queue");
    					if (!queue.offer(data,2, TimeUnit.SECONDS)) {
    						System.out.println("failed to put data: " + data);
    					}
    				}
    			} catch (InterruptedException e) {
    				e.printStackTrace();
    				Thread.currentThread().interrupt();
    			}
    		}
    		public void stop() {
    			isRunning = false;
    		}
    	}
    
    	import java.text.MessageFormat;
    	import java.util.Random;
    	import java.util.concurrent.BlockingQueue;
    
    	/**
    	 * description:
    	 *
    	 * @author: dawn.he QQ:       905845006
    	 * @email: [email protected]
    	 * @email: [email protected]
    	 * @date: 2019/10/3    10:05 PM
    	 */
    	public class Consumer implements Runnable{
    
    		private BlockingQueue<PCData> queue;
    		private static final int SLEEPTIME = 1000;
    
    		public Consumer(BlockingQueue<PCData> queue) {
    			this.queue = queue;
    		}
    
    		@Override
    		public void run() {
    			System.out.println("start Consumer id=" + Thread.currentThread().getId());
    			Random r = new Random();
    			try {
    				while (true) {
    					PCData data = queue.take();
    					if (null != data) {
    						int re = data.getIntData() * data.getIntData();
    						System.out.println(MessageFormat.format("{0}*{1}={2}",data.getIntData(),data.getIntData(),re));
    						Thread.sleep(r.nextInt(SLEEPTIME));
    					}
    				}
    			} catch (InterruptedException e) {
    				e.printStackTrace();
    				Thread.currentThread().interrupt();
    			}
    		}
    	}
    
    	/**
    	 * description:
    	 *
    	 * @author: dawn.he QQ:       905845006
    	 * @email: [email protected]
    	 * @email: [email protected]
    	 * @date: 2019/10/4    10:19 PM
    	 */
    	import java.util.concurrent.BlockingQueue;
    	import java.util.concurrent.ExecutorService;
    	import java.util.concurrent.Executors;
    	import java.util.concurrent.LinkedBlockingQueue;
    
    	public class Storage {
    
    		// 仓库存储的载体
    		private LinkedBlockingQueue<Object> list = new LinkedBlockingQueue<>(10);
    
    		public void produce() {
    			try{
    				list.put(new Object());
    				System.out.println("【生产者" + Thread.currentThread().getName()
    						+ "】生产一个产品,现库存" + list.size());
    			} catch (InterruptedException e){
    				e.printStackTrace();
    			}
    		}
    
    		public void consume() {
    			try{
    				list.take();
    				System.out.println("【消费者" + Thread.currentThread().getName()
    						+ "】消费了一个产品,现库存" + list.size());
    			} catch (InterruptedException e){
    				e.printStackTrace();
    			}
    		}
    
    		public static void main(String[] args) throws InterruptedException {
    	//       Storage storage =  new Storage();
    	//        storage.produce();
    	//        storage.consume();
    
    				BlockingQueue<PCData> queue = new LinkedBlockingQueue<>(10);
    				Producer producer1 = new Producer(queue);
    				Producer producer2 = new Producer(queue);
    				Producer producer3 = new Producer(queue);
    				Consumer consumer1 = new Consumer(queue);
    				Consumer consumer2 = new Consumer(queue);
    				Consumer consumer3 = new Consumer(queue);
    				ExecutorService service = Executors.newCachedThreadPool();
    				service.execute(producer1);
    				service.execute(producer2);
    				service.execute(producer3);
    				service.execute(consumer1);
    				service.execute(consumer2);
    				service.execute(consumer3);
    				Thread.sleep(10 * 1000);
    				producer1.stop();
    				producer2.stop();
    				producer3.stop();
    				Thread.sleep(3000);
    				service.shutdown();
    		}
    	}
    

从BlockingQueue到无锁Disruptor的性能提升:https://blog.csdn.net/weixin_33704591/article/details/92407717

10-05 03:00