1. 创建线程锁
2. 在需要设置加锁的地方（得到锁，释放锁）
3. join 依次检查线程池中是否存在 未死亡的线程，存在则阻塞当前线程

#!/usr/bin/python# -*- coding: UTF-8 -*-import threadingimport timeclass myThread (threading.Thread):    def __init__(self, threadID, name, counter):        threading.Thread.__init__(self)        self.threadID = threadID        self.name = name        self.counter = counter    def run(self):        print "Starting " + self.name       # 获得锁，成功获得锁定后返回True       # 可选的timeout参数不填时将一直阻塞直到获得锁定       # 否则超时后将返回False        threadLock.acquire()        print_time(self.name, self.counter, 3)        # 释放锁        threadLock.release()def print_time(threadName, delay, counter):    while counter:        time.sleep(delay)        print "%s: %s" % (threadName, time.ctime(time.time()))        counter -= 1threadLock = threading.Lock()threads = []# 创建新线程thread1 = myThread(1, "Thread-1", 1)thread2 = myThread(2, "Thread-2", 2)# 开启新线程thread1.start()thread2.start()# 添加线程到线程列表threads.append(thread1)threads.append(thread2)# 等待所有线程完成'''依次检查线程池中是否有未dead的线程，有则阻塞'''for t in threads:    t.join()    print t.getName()print "Exiting Main Thread"