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

Use eclipse to do JSP file, automatically created file table header This error occurred, what should be handled? The Tomcat plugin is already installed.

There is a spot just found, is the Chinese and English punctuation problem, these two, one is the word ' username ' is not correctly spelled, and one is the document body. Contains all the content for the page.

The "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 project class was not added to the Tomcat runtime related classes caused.
Here are the specific workarounds:
1. Right-click Web Project-"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, you need to set up an Apache server if you open the Server runtime blank. Set the method to: Window->preferences->server->runtime environment, add-on, select the Apache version and click Next. Then fill in the installation (unpacked) address of your Apache server software.

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