摘录自这个 Stack Overflow 答案:
Quoting from HandlerIntercepter
's [javadoc][1]:
HandlerInterceptor
is basically similar to a ServletFilter
, but in contrast to the latter it just allows custom pre-processing with the option of prohibiting the execution of the handler itself, and custom post-processing. Filters are more powerful, for example they allow for exchanging the request and response objects that are handed down the chain. Note that a filter gets configured inweb.xml
, aHandlerInterceptor
in the application context.As a basic guideline, fine-grained handler-related preprocessing tasks are candidates for
HandlerInterceptor
implementations, especially factored-out common handler code and authorization checks. On the other hand, aFilter
is well-suited for request content and view content handling, like multipart forms and GZIP compression. This typically shows when one needs to map the filter to certain content types (e.g. images), or to all requests.
With that being said:
So where is the difference between PostHandle() in Interceptor and doFilter() in Filter?
postHandle
will be called after handler method invocation but before the view being rendered. So, you can add more model objects to the view but you can not change the HttpServletResponse
, since it has already committed. doFilter
is much more versatile than the postHandle
. You can change the request or response and pass it to the chain or even block the request processing.
Also, in preHandle
and postHandle
methods you have access to the HandlerMethod
that processed the request. So, you can add pre-post processing logic based on the handler itself. For example, you can add a logic for handler methods that have some annotations.
What is the best practise in which use cases it should be used?
As the doc said, fine-grained handler-related preprocessing tasks are candidates for HandlerInterceptor
implementations, especially factored-out common handler code and authorization checks. On the other hand, a Filter
is well-suited for request content and view content handling, like multipart forms and GZIP compression. This typically shows when one needs to map the filter to certain content types (e.g. images), or to all requests.