Java中多个线程交替循环执行的实现

//首先我们来看一种比较简单的方式
public class ThreadCq {
	
	public static void main(String[] args) {
		 Stack<Integer> stack = new Stack<>();
		 for(int i=1;i<100;i++) {
			 stack.add(i);
		 }
		 Draw draw = new Draw(stack);
		 new Thread(draw).start();
		 new Thread(draw).start();
	}
}

class Draw implements Runnable{
	
	private Stack<Integer> stack;
	public Draw(Stack<Integer> stack) {
		this.stack = stack;
	}
	
	@Override
	public void run() {
		while(!stack.isEmpty()) {
			synchronized (this) {
				notify();
				System.out.println(Thread.currentThread().getName()+"---"+stack.pop());
				try {
					wait();
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			}
		}
	}
}

public class ThreadCq3 {

	//声明一个锁
	static ReentrantLock lock = new ReentrantLock();

	public static void main(String[] args) {
		
		//创建两个Condition对象
		Condition c1 = lock.newCondition();
		Condition c2 = lock.newCondition();
		Stack<Integer> stack = new Stack<>();
		for (int i = 0; i <= 100; i++) {
			stack.add(i);
		}

		new Thread(() -> {
			try {
				Thread.sleep(500);
			} catch (InterruptedException e1) {
				e1.printStackTrace();
			}
			while (true) {
				lock.lock();
				// 打印偶数
				try {
					if (stack.peek() % 2 != 0) {
						c1.await();
					}
					System.out.println(Thread.currentThread().getName() + "-----" + stack.pop());
					c2.signal();
				} catch (InterruptedException e) {
					e.printStackTrace();
				} finally {
					lock.unlock();
				}
			}
		}).start();

		
		new Thread(() -> {
			while (true) {
				try {
					Thread.sleep(500);
				} catch (InterruptedException e1) {
					e1.printStackTrace();
				}
				lock.lock();
				try {
					// 打印奇数
					if (stack.peek() % 2 != 1) {
						c2.await();
					}
					System.out.println(Thread.currentThread().getName() + "-----" + stack.pop());
					c1.signal();
				} catch (InterruptedException e) {
					e.printStackTrace();
				} finally {
					lock.unlock();
				}
			}
		}).start();
	}
}

public class ThreadCq4 {

	//利用信号量来限制
	private static Semaphore s1 = new Semaphore(1);
	private static Semaphore s2 = new Semaphore(1);

	public static void main(String[] args) {
		
		try {
			//首先调用s2为 acquire状态
			s1.acquire();
//			s2.acquire();  调用s1或者s2先占有一个
		} catch (InterruptedException e1) {
			e1.printStackTrace();
		}
		
		new Thread(()->{
			while(true) {
				try {
					s1.acquire();
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				try {
					Thread.sleep(500);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				System.out.println("A");
				s2.release();
			}
		}).start();
		
		new Thread(()->{
			while(true) {
				try {
					s2.acquire();
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				try {
					Thread.sleep(500);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				System.out.println("B");
				s1.release();
			}
		}).start();
	}
}

public class LockCond {

	private static int count = 0;
	private static Lock lock = new ReentrantLock();
	
	
	public static void main(String[] args) {
		Condition c1 = lock.newCondition();
		Condition c2 = lock.newCondition();
		Condition c3 = lock.newCondition();
		
		new Thread(()->{
			while(true) {
				lock.lock();
				try {
					while(count %3 != 0) {
						//刚开始count为0  0%3=0 所以此线程执行  执行完之后 唤醒现成2，由于此时count已经进行了++，所有while成立，c1进入等待状态，其他两个也一样
						c1.await();
					}
					System.out.println(Thread.currentThread().getName()+"========:A");
					count++;
					//唤醒线程2
					c2.signal(); 
				} catch (InterruptedException e) {
					e.printStackTrace();
				} finally {
					lock.unlock();
				}
			}
		}) .start();
		
		new Thread(()->{
			while(true) {
				lock.lock();
				try {
					while(count %3 != 1) {
						c2.await();
					}
					System.out.println(Thread.currentThread().getName()+"========:B");
					count++;
					//唤醒线程3
					c3.signal();
				} catch (InterruptedException e) {
					e.printStackTrace();
				} finally {
					lock.unlock();
				}
			}
		}) .start();
		
		new Thread(()->{
			while(true) {
				lock.lock();
				try {
					while(count %3 != 2) {
						c3.await();
					}
					System.out.println(Thread.currentThread().getName()+"========:C");
					count++;
					//唤醒线程1
					c1.signal();
				} catch (InterruptedException e) {
					e.printStackTrace();
				} finally {
					lock.unlock();
				}
			}
		}) .start();
	}
	
}