简单了解Java中的可重入锁

package reentrantLock;
 
public class Test implements Runnable{
 
  public synchronized void get(){
    System.out.println(Thread.currentThread().getId());
    set();
  }
 
  public synchronized void set(){
    System.out.println(Thread.currentThread().getId());
  }
 
  @Override
  public void run() {
    get();
  }
  public static void main(String[] args) {
    Test ss=new Test();
    new Thread(ss).start();
    new Thread(ss).start();
    new Thread(ss).start();
  }
}

package reentrantLock;
 
import java.util.concurrent.locks.ReentrantLock;
 
public class Test implements Runnable {
  ReentrantLock lock = new ReentrantLock();
 
  public void get() {
    lock.lock();
    System.out.println(Thread.currentThread().getId());
    set();
    lock.unlock();
  }
 
  public void set() {
    lock.lock();
    System.out.println(Thread.currentThread().getId());
    lock.unlock();
  }
 
  @Override
  public void run() {
    get();
  }
 
  public static void main(String[] args) {
    Test ss = new Test();
    new Thread(ss).start();
    new Thread(ss).start();
    new Thread(ss).start();
  }
}

public class SpinLock {
	private AtomicReference<Thread> owner =new AtomicReference<>();
	public void lock(){
		Thread current = Thread.currentThread();
		while(!owner.compareAndSet(null, current)){
		}
	}
	public void unlock (){
		Thread current = Thread.currentThread();
		owner.compareAndSet(current, null);
	}
}

public class SpinLock1 {
	private AtomicReference<Thread> owner =new AtomicReference<>();
	private int count =0;
	public void lock(){
		Thread current = Thread.currentThread();
		if(current==owner.get()) {
			count++;
			return ;
		}
 
		while(!owner.compareAndSet(null, current)){
 
		}
	}
	public void unlock (){
		Thread current = Thread.currentThread();
		if(current==owner.get()){
			if(count!=0){
				count--;
			}else{
				owner.compareAndSet(current, null);
			}
 
		}
 
	}
}