站在API角度再看同步锁

静态锁对象

public class ThreadLock {
    public static Object  obj= new Object();
}

API

@RequestMapping("/thread")
@RestController

public class ThreadController {

    @GetMapping("carAccess")
    public String carAccess(@RequestParam("carNumber") String carNumber) throws InterruptedException {
        System.out.println("车牌号{"+carNumber+"}正在排队");
        synchronized (ThreadLock.obj){
            ThreadLock.obj.wait();
        }
        System.out.println("车牌号{"+carNumber+"}已经驶离缴费站");
        return null;
    }
    @GetMapping("carNotify")
    public String notifyCar(){
        synchronized (ThreadLock.obj){
            ThreadLock.obj.notify();
        }
        return null;
    }
    @GetMapping("carNotifyAll")
    public String NotifyAllCar(){
        synchronized (ThreadLock.obj){
            ThreadLock.obj.notifyAll();
        }
        return null;
    }
}

实验1：请求三次carAccess且携带不同参数，然后请求notify接口

###
GET http://localhost:8888/thread/carAccess?carNumber=001
###
GET http://localhost:8888/thread/carAccess?carNumber=002
###
GET http://localhost:8888/thread/carAccess?carNumber=003

###
GET http://localhost:8888/thread/carNotify

发现请求一次，释放一把锁且安装按照顺序释放锁

实验2：请求三次carAccess且携带不同参数，然后请求notifyAll接口

###
GET http://localhost:8888/thread/carNotifyAll

发现一次性释放三把锁且锁的释放顺序有一定的随机性