为什么Strut2.x要改变Struts1中Action的单例模式,而为每个request申请一个Action实例?

Question

RT

在DOC看到他们两的区分,但并没有找到为什么这么做

Threading Model

Struts 1 Actions are singletons and must be thread-safe since there will only be one instance of a class to handle all requests for that Action. The singleton strategy places restrictions on what can be done with Struts 1 Actions and requires extra care to develop. Action resources must be thread-safe or synchronized.

Struts 2 Action objects are instantiated for each request, so there are no thread-safety issues. (In practice, servlet containers generate many throw-away objects per request, and one more object does not impose a performance penalty or impact garbage collection.)