Java并发练习

1.按顺序打印ABC

     三个线程，每个线程分别打印A,B,C各十次，现在要求按顺序输出A,B,C

package concurrency;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class 按顺序打印ABC {

    public static void main(String[] args) {
        ExecutorService threadPool = Executors.newFixedThreadPool(3);
        Object lockA = new Object();
        Object lockB = new Object();
        Object lockC = new Object();
        Runnable rA = new OrderPrintABC(lockC, lockA, "A");
        Runnable rB = new OrderPrintABC(lockA, lockB, "B");
        Runnable rC = new OrderPrintABC(lockB, lockC, "C");
        threadPool.execute(rA);
        try {
            Thread.sleep(10);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        threadPool.execute(rB);
        threadPool.execute(rC);
        threadPool.shutdown();
    }
    
    private static class OrderPrintABC implements Runnable{

        private Object preLock;
        private Object selfLock;
        private String taskName;
        private int count = 10;
        
        public OrderPrintABC(Object preLock, Object selfLock, String taskName) {
            this.preLock = preLock;
            this.selfLock = selfLock;
            this.taskName = taskName;
        }
        
        @Override
        public void run() {
            while(count > 0) {
                synchronized(preLock) {
                    synchronized(selfLock) {
                        System.out.print(taskName);
                        count--;
                        selfLock.notifyAll();
                    }
                    if(count > 0) {
                        try {
                            preLock.wait();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                }
            }
        }
}
}

 

2. 生产者消费者： 要尽量使用BlockingQueue来实现

https://github.com/CyC2018/CS-Notes/blob/master/notes/Java%20%E5%B9%B6%E5%8F%91.md#blockingqueue

package concurrency;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

public class 生产者消费者 {

    //有界队列
    private static class BoundQueue<T> {
        private Object[] items;
        private int count = 0;
        private Lock lock = new ReentrantLock();
        private Condition notEmpty = lock.newCondition();
        private Condition notFull = lock.newCondition();
        
        public BoundQueue(int size) {
            items = new Object[size];
        }
        
        public void add(T t) throws InterruptedException {
            lock.lock();
            try {
                Long nano = 0L;
                while (count == items.length) {
                    if(nano < 0L) {
                        return;
                    };
                    System.out.println("仓库已满");
                    notFull.awaitNanos(5000);
                }
                items[count++] = t;
                System.out.println("生产者放入" + t);
                notEmpty.signal();
                Thread.sleep(1000);
            } finally {
                lock.unlock();
            }
        }
        
        public T remove() throws InterruptedException {
            lock.lock();
            T t;
            try {
                Long nano = 0L;
                while (count == 0) {
                    if(nano < 0L) {
                        return null;
                    };
                    System.out.println("仓库已空");
                    nano = notEmpty.awaitNanos(5000);
                }
                t = (T) items[count - 1];
                items[--count] = null;
                System.out.println("消费者接收" + t);
                notFull.signal();
                Thread.sleep(1000);
            } finally {
                lock.unlock();
            }
            return t;
        }
    }
    
    //生产者
    private static class Product implements Runnable{
        private BoundQueue queue;
        private int count;
        
        public Product (BoundQueue queue, int count) {
            this.queue = queue;
            this.count = count;
        }
        
        public void run() {
            int itr = 1;
            while(itr <= count) {
                try {
                    queue.add(itr);
                    itr++;
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }
    
    //消费者
    private static class Consumer implements Runnable{
        private BoundQueue queue;
        private int count;
        
        public Consumer(BoundQueue queue, int count) {
            this.queue = queue;
            this.count = count;
        }

        @Override
        public void run() {
            int itr = 0;
            while(itr <= count) {
                try {
                    queue.remove();
                    itr++;
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }
    
    public static void main(String[] args) {
        BoundQueue<Integer> queue = new BoundQueue<>(5);
        int count = 6;
        Runnable rP = new Product(queue, count);
        Runnable rC = new Consumer(queue, count);
        ExecutorService threadPool = Executors.newFixedThreadPool(2);
        threadPool.execute(rP);
        threadPool.execute(rC);
        threadPool.shutdown();
    }
}

 

https://github.com/CyC2018/CS-Notes/blob/master/notes/Java%20%E5%B9%B6%E5%8F%91.md#blockingqueue