Eclipse import Java Web Engineering JSP file error: The superclass "Javax.servlet.http.HttpServlet" was not found on the Java

When Eclipse imports a Java Web project, it may cause all JSP files in the project to complain: the superclass "Javax.servlet.http.HttpServlet" is not found on the Java. This is because the class required for the Tomcat runtime is not added to the project. The specific reason may be that the server version used in the imported project is different from the server version in Eclipse. The workaround is as follows:

Right-click Web Engineering-->properties (properties)-> Left select Java Build path-->libraries tab-->add libray-->server runtime--> Next--> Select a Tomcat server-->finish