练手java thread(二)

最新推荐文章于 2024-04-27 14:46:02 发布

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#thread #Java #OOP

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本文介绍了一个简单的生产者消费者模式实现，通过同步方法控制共享资源的访问。生产者负责填充数据，而消费者则移除数据，两者通过同一个共享队列进行交互。

生产者、消费者模型的demo:

1.程序入口:

package thread.test01;

public class ThreadCommunication {

	public static void main(String[] args) {
		Queue q = new Queue();
		new Thread(new Producer(q)).start();
		new Thread(new Consumer(q)).start();
	}
}

2.共享数据列表:

package thread.test01;

public class Queue {
	String name = "unknown";
	String sex = "unknown";
	boolean bFull = false;
}

3.生产者：

package thread.test01;

public class Producer implements Runnable {
	private Queue q;

	public Producer(Queue q) {
		this.q = q;
	}

	@Override
	public void run() {
		int i = 0;
		while (true) {
			synchronized (q) {// 当前线程得到对象q的lock旗标
				if (q.bFull) {
					try {
						q.wait();// 此时当前线程被放置在对象q的等待池中,当前线程释放q的锁旗标
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
				}
				if (i == 0) {
					q.name = "zhangsan";
					try {
						Thread.sleep(10);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
					q.sex = "male";
				} else {
					q.name = "wangwu";
					q.sex = "female";
				}
				q.bFull = true;
				q.notify();// 当另外的线程执行了对象o的notify()方法后,当前线程可能会被从q的等待
				// 线程池中释放出来,并且移动到等待线程对象q的锁旗标的线程池中,当当前 
				//线程得到的锁旗标时就会执行下去
			}
			i = (i + 1) % 2;
		}
	}

}

4.消费者：

package thread.test01;

public class Consumer implements Runnable {
	private Queue q;

	public Consumer(Queue q) {
		this.q = q;
	}

	@Override
	public void run() {
		while (true) {
			synchronized (q) {
				if (!q.bFull) {
					try {
						q.wait();
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
				}
				System.out.print(q.name);
				System.out.println(":" + q.sex);
				q.name = "unknown";
				q.sex = "unknown";
				q.bFull = false;
				q.notify();
			}
		}

	}

}

理解监视器对象、synchronized、wait、notify之间的关系是根本。

根据oop的设计，重构以上代码：

package thread.test02;

public class Queue {
	private String name = "unknown";
	private String sex = "unknown";
	private boolean bFull = false;

	public synchronized void put(String name, String sex) {
		if (bFull) {
			try {
				this.wait();
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
		this.name = name;
		try {
			Thread.sleep(10);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		this.sex = sex;
		bFull = true;
		this.notifyAll();
	}

	public synchronized void get() {
		if (!bFull) {
			try {
				this.wait();
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
		System.out.println(name+":"+sex);
		try {
			Thread.sleep(10);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		bFull = false;
		this.notifyAll();
	}
}

package thread.test02;

public class Producer implements Runnable {
	private Queue q;

	public Producer(Queue q) {
		this.q = q;
	}

	@Override
	public void run() {
		int i = 0;
		while (true) {
			if (i == 0) {
				q.put("zhangsan", "male");
			} else {
				q.put("wangwu", "female");
			}
			i = (i + 1) % 2;
		}
	}

}

package thread.test02;

public class Consumer implements Runnable {
	private Queue q;

	public Consumer(Queue q) {
		this.q = q;
	}

	@Override
	public void run() {
		while (true) {
			q.get();
		}

	}

}