题目:两个线程交替顺序打印,一个输出正整数1到52,一个输出a-zA-Z,
例如 - 1a2b3c4d5e6f7g8h9i10j11k12l13m14n15o16p17q18r19s20t21u22v23w24x25y26z
27A28B29C30D31E32F33G34H35I36J37K38L39M40N41O42P43Q44R45S46T47U48V49W50X51Y52Z
一、使用volatile
二、使用Semaphore
三、思路: 一个线程等待,一个线程唤醒,始终只有一个线程执行
a. volatile
public class NumberDemo { static class Inner { private volatile boolean flag = true; private int count = 1; private int index = 1; public synchronized void printNum() { try { while (!flag) { this.wait(); } } catch (InterruptedException e) { e.printStackTrace(); } System.out.print(count++); flag = false; this.notify(); } public synchronized void printChar() { try { while (flag) { this.wait(); } } catch (InterruptedException e) { e.printStackTrace(); } if (index < 27) { System.out.print((char) (index + ‘a‘ - 1)); } else { System.out.print((char) (index + ‘A‘ - 27)); } index++; flag = true; this.notify(); } } public static void main(String[] args) { Inner inner = new Inner(); new Thread(new Runnable() { @Override public void run() { for (int i = 0; i < 52; i++) { inner.printNum(); } } }).start(); new Thread(new Runnable() { @Override public void run() { for (int i = 0; i < 52; i++) { inner.printChar(); } } }).start(); } }
b. Semaphore
public class NumberSemaphoreDemo { static class Inner { private Semaphore semaphore = new Semaphore(1); private int count = 1; private int index = 1; public synchronized void printNum() { try { semaphore.acquire(); this.wait(); } catch (InterruptedException e) { e.printStackTrace(); } System.out.print(count++); semaphore.release(); this.notify(); } public synchronized void printChar() { try { semaphore.acquire(); this.wait(); } catch (InterruptedException e) { e.printStackTrace(); } if (index < 27) { System.out.print((char) (index + ‘a‘ - 1)); } else { System.out.print((char) (index + ‘A‘ - 27)); } index++; semaphore.release(); this.notify(); } } public static void main(String[] args) { NumberDemo.Inner inner = new NumberDemo.Inner(); new Thread(new Runnable() { @Override public void run() { for (int i = 0; i < 52; i++) { inner.printNum(); } } }).start(); new Thread(new Runnable() { @Override public void run() { for (int i = 0; i < 52; i++) { inner.printChar(); } } }).start(); } }
原文地址:https://www.cnblogs.com/maduar/p/10605674.html
时间: 2024-10-18 19:08:33