错误代码 503

Question

写了个 Filter 就出现这错误
配置 <filter>
   <filter-name>UserFilter</filter-name>
   <fllter-class>shop.Filter.UserFilter</fllter-class>
  </filter>
  <filter-mapping>
   <filter-name>UserFilter</filter-name>
   <url-pattern>/program/*</url-pattern>
  </filter-mapping>
package shop.Filter;import java.io.IOException;import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;public class UserFilter implements Filter{ public void destroy() {


}
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest hrequest=(HttpServletRequest)request;
HttpServletResponse hresponse=(HttpServletResponse)response;
HttpSession session=hrequest.getSession();
String userNum=(String) session.getAttribute("userNum");
if(userNum.length()>0 && userNum!=null){
chain.doFilter(request, response);
}else {
hrequest.setAttribute("NotLogin","请登录");
hrequest.getRequestDispatcher("/userLogin.jsp").forward(hrequest,hresponse);
}


}
public void init(FilterConfig arg0) throws ServletException {

}}

Answer 1

控制台没异常  在网页打开显示 503 错误