递归锁 其实就是维护一个计数器 比如A 线程 获得了锁 那么计数器会+1  释放的时候 为0  如果这个计数器不为0  那么其他的线程无法获得锁 只能慢慢的等待

import  threading
import time


class MyThread(threading.Thread):

    def actionA(self):

        r_lcok.acquire() #count=1
        print(self.name,"gotA",time.ctime())
        time.sleep(2)
        r_lcok.acquire() #count=2

        print(self.name, "gotB", time.ctime())
        time.sleep(1)

        r_lcok.release() #count=1
        r_lcok.release() #count=0


    def actionB(self):

        r_lcok.acquire()
        print(self.name, "gotB", time.ctime())
        time.sleep(2)

        r_lcok.acquire()
        print(self.name, "gotA", time.ctime())
        time.sleep(1)

        r_lcok.release()
        r_lcok.release()


    def run(self):

        self.actionA()
        self.actionB()


if __name__ == '__main__':

    # A=threading.Lock()
    # B=threading.Lock()

    r_lcok=threading.RLock()
    L=[]

    for i in range(5):
        t=MyThread()
        t.start()
        L.append(t)


    for i in L:
        i.join()

    print("ending....")

Thread-1 gotA Sat Jan 26 11:24:35 2019
Thread-1 gotB Sat Jan 26 11:24:37 2019
Thread-1 gotB Sat Jan 26 11:24:38 2019
Thread-1 gotA Sat Jan 26 11:24:40 2019
Thread-3 gotA Sat Jan 26 11:24:41 2019
Thread-3 gotB Sat Jan 26 11:24:43 2019
Thread-3 gotB Sat Jan 26 11:24:44 2019
Thread-3 gotA Sat Jan 26 11:24:46 2019
Thread-5 gotA Sat Jan 26 11:24:47 2019
Thread-5 gotB Sat Jan 26 11:24:49 2019
Thread-5 gotB Sat Jan 26 11:24:50 2019
Thread-5 gotA Sat Jan 26 11:24:52 2019
Thread-4 gotA Sat Jan 26 11:24:53 2019
Thread-4 gotB Sat Jan 26 11:24:55 2019
Thread-4 gotB Sat Jan 26 11:24:56 2019
Thread-4 gotA Sat Jan 26 11:24:58 2019
Thread-2 gotA Sat Jan 26 11:24:59 2019
Thread-2 gotB Sat Jan 26 11:25:01 2019
Thread-2 gotB Sat Jan 26 11:25:02 2019
Thread-2 gotA Sat Jan 26 11:25:04 2019
ending....