Difference between Interceptor and Filter in Spring MVC

Question

I m a little bit confused about Filter and Interceptor purposes    As I understood from docs  Interceptor is run between requests  On the other hand Filter is run before rendering view  but after Controller rendered response    So where is the difference between postHandle   in Interceptor and doFilter   in Filter     What is the best practise in which use cases it should be used  In this picture where works Filters and Interceptors

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Filter  - A filter as the name suggests is a Java class executed by the servlet container for each incoming HTTP request and for each http response  This way  is possible to manage HTTP incoming requests before them reach the resource  such as a JSP page  a servlet or a simple static page  in the same way is possible to manage HTTP outbound response after resource execution   Interceptor  - Spring Interceptors are similar to Servlet Filters but they acts in Spring Context so are many powerful to manage HTTP Request and Response but they can implement more sophisticated behavior because can access to all Spring context

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From HandlerIntercepter s javadoc      HandlerInterceptor is basically similar to a Servlet Filter  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 in web xml  a   HandlerInterceptor in the application context       As a basic guideline  fine-grained handler-related pre-processing 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    With that being said      So where is the difference between Interceptor postHandle   and   Filter doFilter      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 s 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 pre-processing 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

User · Answer

A HandlerInterceptor gives you more fine-grained control than a filter  because you have access to the actual target  handler  - this means that whatever action you perform can vary depending on what the request is actually doing  whereas the servlet filter is generically applied to all requests - only able to take into account the parameters of each request   The handlerInterceptor also provides 3 different methods  so that you can apply behavior prior to calling a handler  after the handler has completed but prior to view rendering  where you may even bypass view rendering altogether   or after the view itself has been rendered  Also  you can set up different interceptors for different groups of handlers - the interceptors are configured on the handlerMapping  and there may be multiple handlerMappings   Therefore  if you have a need to do something completely generic  e g  log all requests   then a filter is sufficient - but if the behavior depends on the target handler or you want to do something between the request handling and view rendering  then the HandlerInterceptor provides that flexibility   Reference  http   static springframework org sp   ng-interceptor

[java] Difference between Interceptor and Filter in Spring MVC

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