在更换tomcat版本后，原来的项目文件中jsp会出现错误The superclass "javax.servlet.http.HttpServlet" was not found on the Java Build Path
这时候只需要：右键项目-build path-configure build path-java build path-Add Library-server Runtime-(Apache Tomcat)-Finsh
在更换tomcat版本后，原来的项目文件中jsp会出现错误The superclass "javax.servlet.http.HttpServlet" was not found on the Java Build Path
这时候只需要：右键项目-build path-configure build path-java build path-Add Library-server Runtime-(Apache Tomcat)-Finsh