【JavaEE企业应用实战学习记录】authorityFilter

 package sanglp.servlet;

 import javax.servlet.*;
 import javax.servlet.annotation.WebFilter;
 import javax.servlet.annotation.WebInitParam;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpSession;
 import java.io.IOException;

 /**
  * Created by Administrator on 2016/10/5.
  */
 @WebFilter(filterName = "authority",urlPatterns = {"/*"},initParams = {
     @WebInitParam(name = "encoding",value = "UTF-8"),
         @WebInitParam(name = "loginPage",value = "/chap2/login.jsp"),
         @WebInitParam(name = "proLogin", value="/chap2/proLogin.jsp")
 })
 public class AuthorityFilter implements Filter {
     //用于访问Filter的配置信息
     private FilterConfig config;

     @Override
     public void init(FilterConfig filterConfig) throws ServletException {
         this.config=filterConfig;
     }

     @Override
     public void destroy() {
         this.config=null;
     }

     @Override
     public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
         //获取该Filter的配置参数
         String encoding=config.getInitParameter("encoding");
         String loginPage=config.getInitParameter("loginPage");
         String proLogin=config.getInitParameter("proLogin");
         //设置request编码用的字符集
         servletRequest.setCharacterEncoding(encoding);
         HttpServletRequest hreq=(HttpServletRequest) servletRequest;
         HttpSession session=hreq.getSession(true);
         //获取客户请求的页面
         String requestPath=hreq.getServletPath();
         //如果session范围的user为null即表明没有邓丽。且用户请求的既不是登录页面，也不是处理登录的页面
         if(session.getAttribute("user")==null&&!requestPath.endsWith(loginPage)&&!requestPath.endsWith(proLogin)){
             servletRequest.setAttribute("tip","您还没有登录");
             servletRequest.getRequestDispatcher(loginPage).forward(servletRequest,servletResponse);

         }else{
             //履行请求
             filterChain.doFilter(servletRequest,servletResponse);
         }
     }
 }