import javax.servlet.ServletException出错

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

出错的问题大概就是缺少servlet的jar包

网上搜素servlet.jar下载就可以了，然后复制到lib下