在多线程中，为了避免出现假唤醒的情况，所有的判断都是用while来判断的

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

//准备资源
class ShareData {
	private int number = 0;
	
	//synchronized版本
	//+1
	/*public synchronized void increment() throws Exception {
		while(number!=0) {
			this.wait();
		}
		++number;
		System.out.println(Thread.currentThread().getName() + "\t" + number);
		this.notifyAll();
	}
	//-1
	public synchronized void decrement() throws Exception {
		while(number == 0 ) {
			this.wait();
		}
		--number;
		System.out.println(Thread.currentThread().getName() + "\t" + number);
		this.notifyAll();
	}*/
	//JUC版本
	private Lock lock = new ReentrantLock();
	private Condition condition = lock.newCondition();
	
	//+1
	public void increment() throws Throwable {
		lock.lock();
		try {
			while(number!=0) {
				condition.await();
			}
			++number;
			System.out.println(Thread.currentThread().getName() + "\t" + number);
			condition.signalAll();
		} finally {
			lock.unlock();
		}
	}
	//-1
	
	public void decrement() throws Throwable {
		lock.lock();
		try {
			while(number==0) {
				condition.await();
			}
			--number;
			System.out.println(Thread.currentThread().getName() + "\t" + number);
			condition.signalAll();
		} finally {
			// TODO: handle finally clause
			lock.unlock();
		}
	}
}
/**
 * 
 * @author MaJiatao
 * 在多线程中为了避免假唤醒，条件的判断需要用while来进行判断，而不能使用if
 */
public class NotifyWaitDemo {
	public static void main(String[] args) {
		ShareData shareData = new ShareData();
		new Thread(()-> {
				for (int i = 0; i < 10; i++) {
					try {
						shareData.increment();
					} catch (Throwable e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}	
				}
		},"A").start();
		new Thread(()-> {
			try {
				for (int i = 0; i < 10; i++) {
					try {
						shareData.decrement();
					} catch (Throwable e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}					
				}
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		},"B").start();
		new Thread(()-> {
			try {
				for (int i = 0; i < 10; i++) {
					try {
						shareData.increment();
					} catch (Throwable e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
				}
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		},"C").start();
		new Thread(()-> {
				for (int i = 0; i < 10; i++) {
					try {
						shareData.decrement();
					} catch (Throwable e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}					
				}
		},"D").start();
	}
}