You'll need to include the struts jar into the classpath (depending upon the version of struts, the needed jars will vary). I would recommend that you use an IDE (eclipse or netbeans etc) or a build script (ant or maven)...
Output:
C:\strutsprac-war\WEB-INF\classes>javac -d *.java
EmployeeAction.java:2: package javax.servlet does not exist
import javax.servlet.ServletException;
^
EmployeeAction.java:3: package javax.servlet.http does not exist
import javax.servlet.http.*;
^
EmployeeAction.java:14: cannot find symbol
symbol : class HttpServletRequest location: class org.EmployeeAction
public ActionForward perform (ActionMapping mappings,ActionForm form,HttpServletRequest req, HttpServletResponse res)throws ServletException,IOException{
^