一個容器，兩個方法put()和get()方法

兩個生產者，十個消費者，生產者生產達到MAX數量時阻塞，消費者消費到MAX數量為0時阻塞。

使用CAS加鎖

public class TestReetrantLock1 {

    private static LinkedList<Object> list=new LinkedList<Object>();
    private int MAX=10;
    private int count;

    private ReentrantLock lock=new ReentrantLock();
    private
 
 Condition prod=lock.newCondition();
    private Condition cons=lock.newCondition();

    public void put(Object t) {
        try {
            lock.lock();
            while (list.size()==MAX){
                System.out.println("容器中已經放滿，停止生產");
                prod.await();
            }
            System.out.println(
 
"容器開始存放");
            list.add(t);
            ++count;
            System.out.println("容器現在存放"+count);
            cons.signalAll();//通知消費者執行緒消費
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            lock.unlock();
        }

    }

    public synchronized Object get(){
        Object t
 
=null;

        try{
            lock.lock();
            while (list.size()==0){
                System.out.println("容器中已經空了，停止消費");
                cons.await();
            }
            System.out.println("容器開始消費");
            t=list.removeFirst();
            count--;
            System.out.println("容器現在剩餘"+count);
            prod.signalAll();
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            lock.unlock();
        }

        return t;
    }
    public static void main(String[] args) {
        TestReetrantLock t=new TestReetrantLock();
        //消費者
        for (int i = 0; i <10 ; i++) {
            new Thread(()->{
                for (int j = 0; j <5 ; j++) {
                    t.get();
                }
            }).start();
        }
        try{
            TimeUnit.SECONDS.sleep(1);
        }catch (Exception e){
            e.printStackTrace();
        }
        //生產者
        for (int i = 0; i <2 ; i++) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    for (int j = 0; j <25 ; j++) {
                        t.put(Thread.currentThread().getName());
                    }
                }
            }).start();
        }

    }
}

使用synchronized加鎖

public class TestReetrantLock {

    private static LinkedList<Object> list=new LinkedList<Object>();
    private int MAX=10;
    private int count;

    public synchronized void put(Object t) {//加鎖因為++count非原子操作
        while (list.size() == MAX){//注意此處為什麼是while而不是if?
            try {
                System.out.println("容器中已經放滿，停止生產");
                this.wait();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        System.out.println("容器開始存放");
        list.add(t);
        ++count;
        System.out.println("容器現在存放"+count);
        this.notifyAll();//喚醒其它執行緒
    }

    public synchronized Object get(){
        Object t=null;
        while (list.size()==0){
            try{
                System.out.println("容器中已經空了，停止消費");
                this.wait();
            }catch (Exception e){
                e.printStackTrace();
            }

        }
        System.out.println("容器開始消費");
        t=list.removeFirst();
        count--;
        System.out.println("容器現在剩餘"+count);
        this.notifyAll();
        return t;
    }
    public static void main(String[] args) {
        TestReetrantLock t=new TestReetrantLock();
        //消費者
        for (int i = 0; i <10 ; i++) {
            new Thread(()->{
                for (int j = 0; j <5 ; j++) {
                    t.get();
                }
            }).start();
        }
        try{
            TimeUnit.SECONDS.sleep(1);
        }catch (Exception e){
            e.printStackTrace();
        }
        //生產者
        for (int i = 0; i <2 ; i++) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    for (int j = 0; j <25 ; j++) {
                        t.put(Thread.currentThread().getName());
                    }
                }
            }).start();
        }

    }


}