JAVA 多线程轮流打印ABC

采用Thread+Semaphore实现，思路很简单

 import java.io.IOException;
 import java.util.concurrent.Semaphore;

 public class PrintABC {
     public static int MAX_TIME = 10;

     public static class PrintThread extends Thread {
         private String printChar;
         private Semaphore curSemaphore, nextSemaphore;

         public PrintThread(String printChar, Semaphore curSemaphore,
                 Semaphore nextSemaphore) {
             this.printChar = printChar;
             this.curSemaphore = curSemaphore;
             this.nextSemaphore = nextSemaphore;
         }

         public void run() {
             for (int i = 0; i < MAX_TIME; ++i) {
                 try {
                     curSemaphore.acquire();  /* 请求打印需要的信号量，资源数-1，即down操作  */
                     System.out.println(printChar);
                     nextSemaphore.release(); /* 释放下一个线程打印需要的信号量，资源数+1，即up操作  */
                 } catch (InterruptedException e) {
                     // TODO Auto-generated catch block
                     e.printStackTrace();
                 }

             }
         }
     }

     public static void main(String[] args) throws IOException {
         Semaphore semaphoreA = new Semaphore(1); /* 只有A信号量的初始资源数为1，保证从A开始打印  */
         Semaphore semaphoreB = new Semaphore(0);
         Semaphore semaphoreC = new Semaphore(0);

         new PrintThread("A", semaphoreA, semaphoreB).start();
         new PrintThread("B", semaphoreB, semaphoreC).start();
         new PrintThread("C", semaphoreC, semaphoreA).start();
     }
 }