TheadLocal 用于多线程环境下，线程之间可以使用相同的变量，而这个变量只与当前线程环境有关。werkzeug中有类似的实现，使每个路由处理函数都可使用相同的request变量，而这个对象的内容只与当前请求有关。
例如:1
import threading
# 创建全局ThreadLocal对象:
local_school = threading.local()
def process_student():
# 获取当前线程关联的student:
std = local_school.student
print('Hello, %s (in %s)' % (std, threading.current_thread().name))
def process_thread(name):
# 绑定ThreadLocal的student:
local_school.student = name
process_student()
t1 = threading.Thread(target= process_thread, args=('Alice',), name='Thread-A')
t2 = threading.Thread(target= process_thread, args=('Bob',), name='Thread-B')
t1.start()
t2.start()
t1.join()
t2.join()
执行结果：
Hello, Alice (in Thread-A)
Hello, Bob (in Thread-B)