Common errors when Eclipse imports a project

Question one, the import Javax.servlet cannot be resolved
Method One: This package is in Tomcat, not in the JDK. Add the Jsp-api.jar and Servlet-api.jar of the Tomcat's Lib folder to the Classpath, you can import the package, you must add Jsp-api.jar, the Internet may be said to add Servlet-api.jar can , this package just unlocks the error, but may access the database after the page shows the struts problem method two:
One, right key project build path--->configure build path----->add Library----->server Runtime---> Specify to the currently running Tomcat environment
Second, right key item click Properties to find targeted runtimes after clicking on him, the right-hand side will have Apache Tomcatv7.0 or other server check on it.
Question two, Can not find the tag library descriptor for "Http://java.sun.com/jsp/jstl/core"

Method: The Jstl.jar and Standard.jar files are missing from the project, putting the two jar files into the Lib directory or under the Tomcat's Lib directory can