After each use, the thread local storage values of username and password are reset to null.
每次使用后，用户名和密码的线程本地存储值都被重新设置为空。
2
Key things to note here are the thread local storage declarations and the instance variables used to hold the potential source of the username and password.
这里需要注意的关键内容是用于存放用户名和密码的可能来源的线程本地存储声明和实例变量。
3
After using thread local storage, the handler sets the thread local username to null.