代码功能：子线程每次循环5次，主线程每次循环10次，子线程先执行，如此交替执行50次。 分析：子线程执行过程中不能被主线程打断，主线程执行过程中不能被子线程打断，因此需要进行互斥，需要交替执行，因此需要进行同步。互斥可以利用synchronized，同步可以采用wait和notify
代码如下：
public class SynchronousTest { public static void main(String[] args) { final Business business = new Business(); Thread sub = new Thread() { @Override public void run() { for (int i = 0; i < 50; i++) { business.sub(i); Thread.yield(); } } }; sub.start(); for (int i = 0; i < 50; i++) { business.main(i); Thread.yield(); } } } class Business { boolean shouldSubRun = true; public synchronized void sub(int i) { while(!shouldSubRun) { try { this.wait(); } catch (InterruptedException e) { e.printStackTrace(); } } for (int j = 0; j < 5; j++) { System.out.println("loop-" + i + " Sub Thread: " + j); } shouldSubRun = false; this.notify(); } public synchronized void main(int i) { while(shouldSubRun) { try { this.wait(); } catch (InterruptedException e) { e.printStackTrace(); } } for (int j = 0; j < 10; j++) { System.out.println("loop-" + i + " Main Thread: " + j); } shouldSubRun = true; this.notify(); } }——致敬张孝祥老师
