Difference between HandlerInterceptor and WebRequestInterceptor?

Question

While writing interceptor for my application I noticed HandlerInterceptor and WebRequestInterceptor here.

I noticed that HandlerInterceptor's method take HttpServletRequest, HttpServletResponse, Object(handler) and other params while WebRequestInterceptor take WebRequest (a wrapper of HttpServletRequest).

But I don't know what is the difference between these two interceptors.

Although seeing Spring API I can guess that WebRequestInterceptor can not commit response while HandlerInterceptor can do that. Please correct me here if I am wrong.

Answer 1

With a HandlerInterceptor you can:

• Change the HttpServletResponse in preHandle method
• Apply filters based on handler object. For example, you can apply some filters based on presence of some annotations on HandlerMethod
• Prohibit the execution of the handler by returning false in preHandle method.

HandlerInterceptor can be used for a large field of preprocessing aspects, e.g. for authorization checks, or common handler behavior like locale, theme changes or adding Cache-Control headers. Its main purpose is to allow for factoring out repetitive handler code.

One of the canonical use cases of WebRequestInterceptor is preparing context resources (such as a Hibernate Session) and expose them as request attributes or as thread-local objects. Also, you can modify those context resources after successful handler execution (for example, flushing a Hibernate Session). For example, OpenEntityManagerInViewInterceptor binds a JPA EntityManager to the thread for the entire processing of the request.

Although seeing Spring API I can guess that WebRequestInterceptor can not commit response while HandlerInterceptor can do that. Please correct me here if I am wrong.

WebRequestInterceptor interface is deliberately minimalistic to keep the dependencies of generic request interceptors as minimal as feasible. If you need to change the response, you should use HandlerIntercepter or Filters.