public class TeatPrintOrder {
	
	public static void main(String args[]){		
		AtomicInteger atomic = new AtomicInteger();		
		Print p = new Print();
		ThreadTest a = new ThreadTest(p,"A",0,10,atomic);
		ThreadTest b = new ThreadTest(p,"B",1,10,atomic);
		ThreadTest c = new ThreadTest(p,"C",2,10,atomic);
		
		a.start();b.start();c.start();
	}
		
}

class ThreadTest extends Thread{
	String name="";
	Integer id ;
	Print tPrint = null;
	int count;
	AtomicInteger atomic ;
	ThreadTest(Print p,String name,Integer id,int count,AtomicInteger atomic){
		this.name = name ;
		this.id= id ;
		this.tPrint = p ;
		this.count = count ;
		this.atomic= atomic ;
	}
	public void run(){
		while(count>0){
			if((atomic.get() % 3) ==id){
				tPrint.PrintName(name);
				atomic.getAndAdd(1);
				count--;
			}
		}
	}
}

class Print{
	void PrintName(String name){
		System.out.print(name);
	}
}
 

1.設計上注意，把列印這個物件獨立出來，以便控制資源的同步

2.使用atomic類原子性控制執行緒的執行，此處的取模，相當於一個變數標識

3.如果是列印一遍，使用執行緒的join()，比較便捷。

static class MyThread extends Thread {
    public MyThread (final String name) {
        super (name);
    }

    @Override
    public void run () {
        System.out.print (currentThread ().getName ());
    }
}

private static void printOnceV2 () throws InterruptedException {
    final MyThread threadA = new MyThread ("A");
    final MyThread threadB = new MyThread ("B");
    final MyThread threadC = new MyThread ("C");
    threadA.start ();
    threadA.join ();        // 等待 A 執行完，再開始 B
    threadB.start ();
    threadB.join ();        // 等待 B 執行完，再開始 C
    threadC.start ();
}