signonfilter.java

《J2EE企业级应用开发》一书的配套源代码

package com.j2eeapp.cdstore.filter;

import javax.servlet.FilterChain;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.ServletException;
import com.j2eeapp.cdstore.bean.ShoppingSession;

public class SignonFilter extends GenericFilter
{
	String LOGIN_PAGE="loginform";
	public void doFilter(final ServletRequest req,final ServletResponse res,FilterChain chain)throws IOException,ServletException
	{
		 HttpServletRequest hreq = (HttpServletRequest)req;
         HttpServletResponse hres = (HttpServletResponse)res;

		 ShoppingSession shoppingSession = (ShoppingSession) hreq.getSession().getAttribute("shoppingSession");
		 if(shoppingSession!=null&&shoppingSession.isLoggedIn())
		 {
		 	chain.doFilter(req,res);
		 	return ;
		 }
		 else
		 	hres.sendRedirect(LOGIN_PAGE);
		 
		 	
	}
}