Lock类提高等待线程的公平性

public class Lock{
    private boolean isLocked      = false;

    private Thread lockingThread = null;

    public synchronized void lock() throws InterruptedException{=

    //自旋锁
    while(isLocked){

        wait();

    }
    //线程调用wait方法后设置对象锁的状态，表示对象锁已经被当前线程锁定

    isLocked = true;
    lockingThread = Thread.currentThread();

}

public synchronized void unlock(){

    if(this.lockingThread != Thread.currentThread()){

         throw new IllegalMonitorStateException(

              "Calling thread has not locked this lock");
         }

    //更改线程锁的状态

    isLocked = false;

    lockingThread = null;

    notify();

    }

}