消費者生產者模式-Java

直接上代碼，先看，然後可以想下：Java5.0後引入Concurrent併發包類，採用非阻塞算法來優化實現多線程操作中的併發問題，而之前採用syncronized鎖算法模式。

package com.zbv.producerAndcustomer;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.LinkedList;
import java.util.Queue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.LinkedBlockingQueue;

/**
 * 生產者\消費者模式
 */
public class App {

    public static Object object = new Object();

    public static void main(String[] args) {

        ExecutorService executorService = Executors.newFixedThreadPool(2);

        //Concurrent併發包 LinkedBlockingQueue<E> 就不需要syncronized鎖處理了
//        Queue<Integer> queue = new LinkedList<>();
        LinkedBlockingQueue<Integer> queue = new LinkedBlockingQueue<>(1);

        final Producer producer = new Producer(queue);
        Customer customer = new Customer(queue);

        executorService.execute(producer);
        executorService.execute(customer);

        try {
            Thread.sleep(10 * 1000);
            producer.stop();
            customer.stop();

            System.out.println("關閉日期=" + timeStr());

            executorService.shutdown();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

    }

    public static String timeStr() {
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:SSS");
        return simpleDateFormat.format(new Date());
    }

    /**
     * 生產者
     */
    public static class Producer implements Runnable {
        private boolean FLAG = true;
        private Queue<Integer> queue;
        private int count;

        public int getCount() {
            return count;
        }

        public Producer(Queue<Integer> queue) {
            this.queue = queue;
        }

        @Override
        public void run() {
            while (FLAG) {
                count++;
                boolean offerResult = false;
                try {
                    synchronized (object) {
                        offerResult = queue.offer(count);
                    }
                    if (offerResult) {
                        System.out.println("日期：" + timeStr() + "   " + Thread.currentThread().getName() + "：生產了第" + count + "產品成功");
                    } else {
                        System.out.println("日期：" + timeStr() + "   " + Thread.currentThread().getName() + "：生產了第" + count + "產品失敗");
                    }
                    Thread.sleep(500);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }

        public void stop() {
            FLAG = false;
        }
    }

    /**
     * 消費者
     */
    public static class Customer implements Runnable {
        private boolean FLAG = true;
        private Queue<Integer> queue;

        public Customer(Queue<Integer> queue) {
            this.queue = queue;
        }

        @Override
        public void run() {
            while (FLAG) {
                Integer result = null;
                try {
                    synchronized (object) {
                        result = queue.poll();
                    }
                    if (result == null) {
                        System.out.println("日期：" + timeStr() + "   " + Thread.currentThread().getName() + "：當前隊列爲空,無法消費，在等待中...");
                    } else {
                        System.out.println("日期：" + timeStr() + "   " + Thread.currentThread().getName() + "：消費了第" + result + "產品");
                    }
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }

        public void stop() {
            FLAG = false;
        }
    }
}

使用Object wait notify的生產者消費者模式：

package com.qzx.learningThread.LearningThread;

import java.util.ArrayList;
import java.util.List;
import java.util.PriorityQueue;
import java.util.Queue;

/**
 * 使用Object wait notify notifyAll寫一個簡單的消費者、生產者模式
 */
public class ConsumerProducerOne {

    private volatile PriorityQueue<String> stringPriorityQueue;

    private static final int CapacitySize = 1;

    private Object lockObj = new Object();

    private volatile boolean needStop = false;

    private final Runnable consumer;
    private final Runnable producer;

    /**
     * 結束實驗
     */
    public void stopTry() {
        needStop = true;
    }

    public ConsumerProducerOne() {
        stringPriorityQueue = new PriorityQueue<>(CapacitySize);
        consumer = new ConsumerRunnable();
        producer = new ProducerRunnable();
        new Thread(consumer).start();
        new Thread(producer).start();
    }

    private class ConsumerRunnable implements Runnable {
        @Override
        public void run() {
            while (!needStop) {
                synchronized (lockObj) {
                    if (stringPriorityQueue.size() <= 0) {
                        System.out.println("倉庫沒有產品了...");
                        try {
                            lockObj.wait();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                            System.out.println("consumer happen interrupted exception" + e);
                        }
                    }
                    String obj = stringPriorityQueue.poll();
                    System.out.println("消費 " + obj);
                    lockObj.notify();
                }
            }
        }
    }

    private class ProducerRunnable implements Runnable {
        @Override
        public void run() {
            while (!needStop) {
                synchronized (lockObj) {
                    if (stringPriorityQueue.size() >= CapacitySize) {
                        System.out.println("倉庫已滿，暫時不需要生產了");
                        try {
                            lockObj.wait();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                            System.out.println("producer happen interrupted exception" + e);
                        }
                    }

//重點：睡眠放在鎖代碼塊外面
//                    try {
//                        Thread.sleep(1000);
//                    } catch (InterruptedException e) {
//                        e.printStackTrace();
//                    }

                    System.out.println("生產第" + (stringPriorityQueue.size() + 1) + "個產品");
                    stringPriorityQueue.offer("這是第" + (stringPriorityQueue.size() + 1) + "個產品");

                    lockObj.notify();
                }

                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }

            }
        }
    }
}

使用Condition的await、signal的生產者消費者模式（這個比object 的wait和notify好用且相對安全）

package com.qzx.learningThread.LearningThread;

import java.util.PriorityQueue;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

public class ConsumerProducerTwo {
    private static final int CapacitySize = 10;
    private PriorityQueue<String> stringPriorityQueue = new PriorityQueue<>(CapacitySize);
    private final Lock lock = new ReentrantLock();

    private Condition consumerCond = lock.newCondition();
    private Condition producerCond = lock.newCondition();

    private volatile boolean needStop = false;

    public void stopTry() {
        needStop = true;
    }

    public ConsumerProducerTwo() {
        new Consumer().start();
        new Producer().start();
    }

    private class Consumer extends Thread {
        public Consumer() {

        }

        @Override
        public void run() {
            super.run();
            while (!needStop) {
                try {
                    lock.lock();
                    if (stringPriorityQueue.size() <= 0) {
                        try {
                            consumerCond.await();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                            System.out.println("consumer happen interrupt exception" + e);
                        }
                    }

                    String obj = stringPriorityQueue.poll();
                    System.out.println("消費 " + obj);
                    producerCond.signal();

                } finally {
                    lock.unlock();
                }
            }
        }
    }

    private class Producer extends Thread {
        public Producer() {

        }

        @Override
        public void run() {
            super.run();
            while (!needStop) {
                try {
                    lock.lock();
                    if (stringPriorityQueue.size() >= CapacitySize) {
                        try {
                            producerCond.await();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                            System.out.println("producer happen interrupt exception" + e);
                        }
                    }

                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }

                    System.out.println("生產第" + (stringPriorityQueue.size() + 1) + "個產品");
                    stringPriorityQueue.offer("這是第" + (stringPriorityQueue.size() + 1) + "個產品");
                    consumerCond.signal();

                } finally {
                    lock.unlock();
                }
            }
        }
    }
}