accessfilter.java

Simple login example for jsp beginner...

package us.souther.simple.login;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.ServletResponse;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import java.io.IOException;
                                                                                
public class AccessFilter implements Filter{
                                                                                
    public void doFilter(ServletRequest  request,
                         ServletResponse response,
                         FilterChain     chain) throws IOException, ServletException{
                                                                                
        HttpServletRequest req = (HttpServletRequest)request;
        HttpSession session  = req.getSession();
        UserBean    userBean = (UserBean)session.getAttribute("userBean");

        String uri = req.getRequestURI();
        uri = uri.substring(uri.lastIndexOf("/"), uri.length());

        //
        // Let them see the menu, and login pages, even if they're not logged in.
        //
        if("/".equals(uri) || "/index.html".equals(uri) 
                           || "/login.do".equals(uri) || "/logout.do".equals(uri)){
            chain.doFilter(request, response);
            return;
        }

        //
        // Must be logged in to ses anything else.
        //
        if(null == userBean){
            LoginBean loginBean = new LoginBean();
            loginBean.setErrorMessage("You must log in first");
            loginBean.setRequestedUrl(req.getRequestURL().toString());
            session.setAttribute("loginBean", loginBean);
            request.getRequestDispatcher("/login.do").forward(request, response);
            return;
        }else{
            chain.doFilter(request, response);
        }
    }
                                                                                
    // These two methods needed for Filter interface.
    public void init(FilterConfig config){}
    public void destroy(){}
}