Solutions that hint HttpServletRequest cannot be referenced in the project about imports in the Eclipse project

Solutions that hint HttpServletRequest cannot be referenced in the project about imports in the Eclipse project

When you use Eclipse to import external Web projects, sometimes you will be prompted HttpServletRequest, Servletactioncontext can not find the situation,
Workaround:
(Note: I have quoted the Struts2 jar package, classpath have, but Eclipse does not know, prompting me to go with BuildPath, very weird)
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Select the item-->properties-->targeted runtimes--> Select the server you use in the right window

In accordance with this method, the problem is solved, but still do not understand.

Servletactioncontext in the jar bag of struts2, why is it related to Tomcat's bag?

In short, with struts2 jar package, do not know how many problems have occurred, more can not, less also not. Not good enough, no;

Version conflicts, or not. It's been a waste of time just with a jar package before you start a project. I really hate struts.

Solutions that hint HttpServletRequest cannot be referenced in the project about imports in the Eclipse project