多線程同步

package thread;
/**
*    
* synchronized關鍵字實現多線程同步
*(1)靜態變量爲全部對象共享，能夠對其加鎖，實如今同步
*(2)靜態方法加鎖，鎖住的是類，也可實現同步
*/
public class PrintNum implements Runnable
{
   private int id;
    
   private static Object lock = new Object();

   public PrintNum( int id)
  {
     this.id = id;
  }

//  方法1：對靜態變量加鎖
//  public void run()
//  {
//
//     synchronized (lock)
//     {
//      for (int i = 0; i < 100; i++)
//      {
//
//        System.out.println("Thread-" + id + ":" + i);
//        }
//    }
//
//  }
   //方法2:對靜態方法加鎖
   public     void run()
  {
      taskHandler(id);
  }
   synchronized public static void taskHandler( int id)
  {
     for ( int i = 0; i < 100; i++)
    {

      System.out.println( "Thread-" + id + ":" + i);
      }
  }
   public static void main(String args[])
  {

     for ( int i = 0; i < 10; i++)
    {
       new Thread( new PrintNum(i)).start();
       //the flowing code just for test
       for( int j = 1;j<10;j++)
      {
         if(j==9)
        {
          System.out.println( "wait me for a while...");         }       }     }     } }