In java web development, the path written by href connection does not exist in the project. Why can it still be opened?

  java, question

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Java web projects all have path maps. In the sevlet framework, it is the servlet-url of the web.xml inside. In spring mvc @requestmapping; In struts, it is the action configuration in struts.xml

The main topic you want to understand is that the url represents a request for resources, and resources are not necessarily actual html pages, but may also be dynamically output through the program of Character Stream and so on.