Issue analysis and solved : No mapping found for HTTP request with URI [/WEB-INF/views/home.html] in DispatcherServlet with name 'appServlet'.

WARN : org.springframework.web.servlet.PageNotFound - No mapping found for HTTP request with URI [/WEB-INF/views/home.html] in DispatcherServlet with name 'appServlet'

I got above PageNotFound (ERROR 404) message while loading home.html page in Spring Web MVC project with Google App Engine nature. But when I use home.jsp then it works fine.

Then I searched and analysed how the flow of servlet container goes through the request.

1. First the DispatcherServlet is invoked by the Servlet Container.

2. The DispatcherServlet finds a mapping which maps to the home method of the Controller and the home method returns a view name "home".

3.Now the DispatcherServlet uses a View Resolver (InternalResourceViewResolver) to find the View to render the model through, since the name is "home", this maps to the /WEB-INF/view/home.html view.

4. Now essentially a call is made to RequestDispatcher.forward("/WEB-INF/views/home.html")

5. The Servlet container at this point tries to find the servlet which can handle /WEB-INF/views/home.html uri - if it had been a .jsp there is a JSPServlet registered which can handle rendering the jsp, however for *.html there is no servlet registered, so the call ends up with the "default servlet", which is registered with a servlet-mapping of / which probably the DispatcherServlet is.

6. Now the Dispatcher servlet does not find a controller to handle request for /WEB-INF/views/home.html and hence the message that I saw during project run.

If you are also getting this type of error and you want this kind of a extension to be handled by the servlet container, say tomcat, you can register *.html extension to be handled by JSPServlet and then it should work cleanly. Or return forward:/resources/HelloWorld.html which will be considered a static file relative to your resources folder.

And one of my friend asked how he would register *.html extension to be handled by JSPServlet. So, I told him that it can be achieved in two simple steps.

1. By adding this servletmapping for the JSP servlet.

jsp
*.html

This tells the application container to use the the JSP servlet when serving html files.

2. Comment out the for text/html mime type (*.html) files so that the container won't handle HTML files as static content.

Happy Debugging !