userpurview.java

有简单的网上书店需求及设计流程

package org.wiely.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;

/**
 * @author wiely
 * @date 2008-6-10
 */
public class UserPurview implements Filter {

	public void init(FilterConfig config) {

	}

	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {

		HttpServletRequest req = (HttpServletRequest) request;
		HttpServletResponse res = (HttpServletResponse) response;
		HttpSession session = req.getSession();

		if (session.getAttribute("user") == null) {
			res.sendRedirect("/bookshop/default.jsp");
		} else {
			chain.doFilter(request, response);
		}
	}

	public void destroy() {

	}
}