写两个线程，一个线程打印1-52，另一个线程打印A-Z，打印顺序为12A34B56C......5152Z

题目：

写两个线程，一个线程打印1-52，另一个线程打印A-Z，打印顺序为12A34B56C......5152Z。要求用线程间的通信。

 /**
  * 写两个线程，第一个线程打印1-52，第二个线程打印A-Z，打印结果为12A34B...5152Z
  */
 public class ThreadPrinter {
     // true打印数字，false打印字母
     private boolean flag = true;

     // 打印字母
     public synchronized void printNumber(String s) {
         try {
             if (!flag) {
                 super.wait();
             }
             System.out.print(s);
             flag = false;
             super.notifyAll();
         } catch (InterruptedException ex) {
         }
     }

     // 打印数字
     public synchronized void printLetter(String s) {
         try {
             if (flag) {
                 super.wait();
             }
             System.out.print(s);
             flag = true;
             super.notifyAll();
         } catch (InterruptedException ex) {
         }
     }

     /**
      *线程2:打印A-Z
      */
     public static class LetterPrintThread extends Thread {
         private ThreadPrinter printer;

         private LetterPrintThread(String name, ThreadPrinter printer) {
             super(name);
             this.printer = printer;
         }

         @Override
         public void run() {
             for (int i = 1; i <= 26; i++) {
                 int temp = i + 64;
                 char c = (char) temp;
                 printer.printLetter(c + " ");
             }
         }

     }

     /**线程1:打印1-52*/
     public static class NumberPrintThread extends Thread {
         private ThreadPrinter printer;

         private NumberPrintThread(String name, ThreadPrinter printer) {
             super(name);
             this.printer = printer;
         }
         @Override
         public void run() {
             for (int i = 1; i <= 26; i++) {
                 String s = (2 * i - 1) + " " + 2 * i + " ";
                 printer.printNumber(s);
             }

         }
     }

     public static void main(String[] args) {
         ThreadPrinter printer = new ThreadPrinter();
         new NumberPrintThread("打印数字线程", printer).start();
         new LetterPrintThread("打印字母线程", printer).start();
     }
 }