一种情况，会造成死锁，，代码如下

import threadingimport timeclass MyThread(threading.Thread):    def actionA(self):        A.acquire()        print(self.name,'gotA',time.ctime())        time.sleep(2)        B.acquire()        print(self.name, 'gotB', time.ctime())        time.sleep(1)        B.release()        A.release()    def actionB(self):        B.acquire()        print(self.name, 'gotB', time.ctime())        time.sleep(2)        A.acquire()        print(self.name, 'gotA', time.ctime())        time.sleep(1)        A.release()        B.release()    def run(self):        self.actionA()        self.actionB()if __name__ == '__main__':    A = threading.Lock()    B = threading.Lock()    L = []    for i in range(5):        t = MyThread()        t.start()        L.append(t)    for i in L:        i.join()    print('ending-------')

 

 

 

用递归锁，可以避免死锁。代码如下

import threadingimport timeclass MyThread(threading.Thread):    def actionA(self):        r_lock.acquire()        print(self.name,'gotA',time.ctime())        time.sleep(2)        r_lock.acquire()        print(self.name, 'gotB', time.ctime())        time.sleep(1)        r_lock.release()        r_lock.release()    def actionB(self):        r_lock.acquire()        print(self.name, 'gotB', time.ctime())        time.sleep(2)        r_lock.acquire()        print(self.name, 'gotA', time.ctime())        time.sleep(1)        r_lock.release()        r_lock.release()    def run(self):        self.actionA()        self.actionB()if __name__ == '__main__':     r_lock = threading.RLock()    L = []    for i in range(5):        t = MyThread()        t.start()        L.append(t)    for i in L:        i.join()    print('ending-------')