public void run() {
   char tmp;
   for (int i = 1; i < 10; i++) {
     tmp = sstack.read();
     System.out.println("向字符缓冲区读出字符:" + tmp);
     try {
       Thread.sleep((int) (Math.random() * 10));
     } catch (InterruptedException e) {
     }
   }
 }