(原)测试 Java中Synchronized锁定对象的用法

今天再android_serial_port中看到了关键字 synchronized;因为刚好在学java和android，所以就查了一下它的用法：

于是把代码中的一小段代码拿了出来，做了一下修改，测试了下，结果出现的情况：

 public class syncThreadDemo {

     public static void main(String[] args) {
         // TODO Auto-generated method stub
         /*测试1*/
 //        Account account = new Account("zhang san", 10000.0f);
 //        AccountOperator accountOperator = new AccountOperator(account);
 //
 //        final int THREAD_NUM = 5;
 //        Thread threads[] = new Thread[THREAD_NUM];
 //        for (int i = 0; i < THREAD_NUM; i ++) {
 //           threads[i] = new Thread(accountOperator, "Thread" + i);
 //           threads[i].start();
 //        }

         /*测试2*/

         Thread thread1=new Thread(new syncThreadDemo().new SendingThread("send1"),"thread1");
         thread1.start();
         Thread thread2=new Thread(new syncThreadDemo().new ReceiveThread("recv1"),"thread2");
         thread2.start();

     }
     /*创建一个内部类来测试synchronized锁定一个对象*/
     static Object mByteReceivedBackSemaphore = new Object();

     private class SendingThread implements Runnable{
         private int i=0;
         private String name;
         //创建一个构造函数
         public SendingThread(String strName) {
             // TODO Auto-generated constructor stub
             this.name=strName;
         }

         @Override
         public void run(){
             while (i<10) {
                 synchronized (mByteReceivedBackSemaphore) {
                     try {
                         // Wait for 100ms before sending next byte, or as soon as
                         // the sent byte has been read back.
                         System.out.println(Thread.currentThread().getName()+": wait");
                         mByteReceivedBackSemaphore.wait(100);
                         i++;
                         System.out.println(Thread.currentThread().getName()+":"+i);
                     }
                     catch (Exception e) {
                         // TODO: handle exception
                     }
                 }
             }
         }
      }

      private class ReceiveThread implements Runnable{
         private int j=0;
         private String name;

         public ReceiveThread(String strName) {
             // TODO Auto-generated constructor stub
             this.name=strName;
         }

         @Override
         public void run(){
             while(j<10){
                 synchronized(mByteReceivedBackSemaphore){
                     System.out.println(Thread.currentThread().getName()+": notify");
                     mByteReceivedBackSemaphore.notify();
                     j++;
                     System.out.println(Thread.currentThread().getName()+":"+j);
                 }
             }
         }
      }
 }

测试结果：

thread1: wait
thread2: notify
thread2:1
thread2: notify
thread2:2
thread2: notify
thread2:3
thread2: notify
thread2:4
thread2: notify
thread2:5
thread2: notify
thread2:6
thread2: notify
thread2:7
thread2: notify
thread2:8
thread2: notify
thread2:9
thread2: notify
thread2:10
thread1:1
thread1: wait
thread1:2
thread1: wait
thread1:3
thread1: wait
thread1:4
thread1: wait
thread1:5
thread1: wait
thread1:6
thread1: wait
thread1:7
thread1: wait
thread1:8
thread1: wait
thread1:9
thread1: wait
thread1:10