Java同步代码块和同步方法原理与应用案例详解

synchronized(对象)
{
  需要同步的代码块;
}

访问控制符 synchronized 返回值类型方法名称(参数)
{
  需要同步的代码;
}

public class threadSynchronization
{
  public static void main( String[] args )
  {
    TestThread t = new TestThread();
    // 启动了四个线程，实现资源共享
    new Thread( t ).start();
    new Thread( t ).start();
    new Thread( t ).start();
    new Thread( t ).start();
  }
}
class TestThread implements Runnable
{
  private int tickets = 5;
  @Override
  public void run()
  {
    while( true )
    {
      synchronized( this )
      {
        if( tickets <= 0 )
          break;
        try
        {
          Thread.sleep( 100 );
        }
        catch( Exception e )
        {
          e.printStackTrace();
        }
        System.out.println( Thread.currentThread().getName() + "出售票" + tickets );
        tickets -= 1;
      }
    }
  }
}

public class threadSynchronization
{
  public static void main( String[] args )
  {
   TestThread t = new TestThread();
   // 启动了四个线程，实现资源共享的目的
   new Thread( t ).start();
   new Thread( t ).start();
   new Thread( t ).start();
   new Thread( t ).start();
  }
}
class TestThread implements Runnable
{
  private int tickets = 5;
 
  public void run()
  {
   while( tickets > 0 )
   {
     sale();
   }
  }
  public synchronized void sale()
  {
   if( tickets > 0 )
   {
     try
     {
      Thread.sleep( 100 );
     }
     catch( Exception e )
     {
      e.printStackTrace();
     }
     System.out.println( Thread.currentThread().getName() + "出售票"
        + tickets );
     tickets -= 1;
   }
  }
}