如何用Filter实现对注册用户是否登录的过滤
package filter;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.* ;
public class UserFilter implements Filter
{
?
?public void init(FilterConfig filterConfig) throws ServletException
?{
?
?}
?
?public void doFilter(ServletRequest request,
??????????? ServletResponse response,
??????????? FilterChain chain) throws ServletException,IOException
?{
? response.setContentType("text/html ;charset=UTF-8");
? request.setCharacterEncoding("UTF-8");
? PrintWriter out=response.getWriter();
?
? HttpServletRequest req=(HttpServletRequest)request;
? HttpSession session=req.getSession();
? //System.out.println(session.getAttribute("user"));
?
?
? if(session.getAttribute("user")!=null){
?? RequestDispatcher rd = null;
?? rd = request.getRequestDispatcher("/index.jsp"); //定向的页面
?? rd.forward(request, response);
? }
? else{
?? RequestDispatcher rd = null;
?? rd = request.getRequestDispatcher("/login.jsp"); //定向的页面
?? rd.forward(request, response);
??
? }
?}
?public void destroy(){}
}
