The superclass "Javax.servlet.http.HttpServlet" is not found on the Java build Path

The superclass "Javax.servlet.http.HttpServlet" is not found on the Java build Path

A "Red" error message appears at the top of the JSP page: the superclass "Javax.servlet.http.HttpServlet" is not found on the Java build Path. The original Javaweb engineering class was not added to the Tomcat runtime related class cause. The following are the specific solutions:
1, right-click Web Engineering-"Properties or Build path-" Java build path->libraries-> Add libray...->server Runtime-"Tomcat Server
2. Switch to Orader and Export in the Java Build path interface and select Tomcat.

Attention:
When you do this, if you open the server runtime after a blank, you need to set the Apache server. Set the method to: Window->preferences->server->runtime environment-> Add--> Select Apache version after dot next, Then fill in your Apache Server Software installation (after decompression) address.