子线程循环10次，接着主线程循环100，接着又回到子线程循环10次，接着再回到主线程又循环100，如此循环50次.

public class ThreadTest {

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
new ThreadTest().init();

}

public void init()
{
final Business business = new Business();
new Thread(
new Runnable()
{

public void run() {
for(int i=0;i<50;i++)
{
business.SubThread(i);
}
}

}

).start();

for(int i=0;i<50;i++)
{
business.MainThread(i);
}
}

private class Business
{
boolean bShouldSub = true;//这里相当于定义了控制该谁执行的一个信号灯
public synchronized void MainThread(int i)
{
if(bShouldSub)
try {
this.wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

for(int j=0;j<5;j++)
{
System.out.println(Thread.currentThread().getName() + ":i=" + i +",j=" + j);
}
bShouldSub = true;
this.notify();

}

public synchronized void SubThread(int i)
{
if(!bShouldSub)
try {
this.wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

for(int j=0;j<10;j++)
{
System.out.println(Thread.currentThread().getName() + ":i=" + i +",j=" + j);
}
bShouldSub = false;
this.notify();
}
}
}

备注：不可能一上来就写出上面的完整代码，最初写出来的代码如下，问题在于两个线程的代码要参照同一个变量，即这两个线程的代码要共享数据，所以，把这两个线程的执行代码搬到同一个类中去：

package com.huawei.interview.lym;

public class ThreadTest {

private static boolean bShouldMain = false;

public static void main(String[] args) {
// TODO Auto-generated method stub
/*new Thread(){
public void run()
{
for(int i=0;i<50;i++)
{
for(int j=0;j<10;j++)
{
System.out.println("i=" + i + ",j=" + j);
}
}
}

}.start();*/

//final String str = new String("");

new Thread(
new Runnable()
{
public void run()
{
for(int i=0;i<50;i++)
{
synchronized (ThreadTest.class) {
if(bShouldMain)
{
try {
ThreadTest.class.wait();}
catch (InterruptedException e) {
e.printStackTrace();
}
}
for(int j=0;j<10;j++)
{
System.out.println(
Thread.currentThread().getName() +
"i=" + i + ",j=" + j);
}
bShouldMain = true;
ThreadTest.class.notify();
}
}
}
}
).start();

for(int i=0;i<50;i++)
{
synchronized (ThreadTest.class) {
if(!bShouldMain)
{
try {
ThreadTest.class.wait();}
catch (InterruptedException e) {
e.printStackTrace();
}
}
for(int j=0;j<5;j++)
{
System.out.println(
Thread.currentThread().getName() +
"i=" + i + ",j=" + j);
}
bShouldMain = false;
ThreadTest.class.notify();
}
}
}

}

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

public class ThreadTest
{
private static Lock lock = new ReentrantLock();
private static Condition subThreadCondition = lock.newCondition();
private static boolean bBhouldSubThread = false;
public static void main(String [] args)
{
ExecutorService threadPool = Executors.newFixedThreadPool(3);
threadPool.execute(new Runnable(){
public void run()
{
for(int i=0;i<50;i++)
{
lock.lock();
try
{
if(!bBhouldSubThread)
subThreadCondition.await();
for(int j=0;j<10;j++)
{
System.out.println(Thread.currentThread().getName() + ",j=" + j);
}
bBhouldSubThread = false;
subThreadCondition.signal();
}catch(Exception e)
{
}
finally
{
lock.unlock();
}
}
}

});
threadPool.shutdown();
for(int i=0;i<50;i++)
{
lock.lock();
try
{
if(bBhouldSubThread)
subThreadCondition.await();
for(int j=0;j<10;j++)
{
System.out.println(Thread.currentThread().getName() + ",j=" + j);
}
bBhouldSubThread = true;
subThreadCondition.signal();
}catch(Exception e)
{
}
finally
{
lock.unlock();
}
}
}
}