java 自旋锁

```java
package 自旋锁的实现;

import java.util.ArrayList;
import java.util.List;


public class Echang {
    public volatile int l = 0;
    public final Integer lock = 0;

    
    public int swap(int s) {

        synchronized (lock) {
             int temp = l;
            l = s;
            return temp;
        }
    }

    public void lock(int i) {
        while (swap(i) != 0) {
        }
    }

    public void unlock() {
        this.l = 0;
    }

    public static void main(String[] args) {
        Echang lock = new Echang();
        List threadList = new ArrayList<>();
        for (int i = 0; i < 10; i++) {
            Thread t = new Thread(new Runnable() {
                @Override
                public void run() {
                    lock.lock(1);
                    System.out.println(Thread.currentThread().getName() + "获取到锁");
                    try {
                        Thread.sleep(2000);
                    } catch (Exception e) {

                    }
                    lock.unlock();
                }
            });
            t.setName("线程" + i);
            threadList.add(t);
        }
        for (int i = 0; i < 10; i++) {
            threadList.get(i).start();
        }
    }
}