SessionFilter.java

/**
 * http://auzll.iteye.com/
 */
package com.gengweibo.web;

import java.io.IOException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

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 com.gengweibo.entity.Account;

/**
 * @author auzll@msn.com
 * @since 2011-3-21
 */
public class SessionFilter implements Filter {

    public void destroy() {}

    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain filter) throws IOException, ServletException {
        String api = request.getParameter("api");
        if (null == api) {
            String queryString = ((HttpServletRequest) request)
                    .getQueryString();
            if (queryString.length() > 0) {
                Pattern pattern = Pattern
                        .compile("(\\?|&){0,1}api=(.*?)&{0,1}");
                Matcher matcher = pattern.matcher(queryString);
                if (matcher.matches() && matcher.groupCount() >= 2) {
                    api = matcher.group(2);
                }
            }
        }

        if (null != api
                && !"link".equalsIgnoreCase(api)
                && !"logout".equalsIgnoreCase(api)
                && !"flush".equalsIgnoreCase(api)
                && null == ((HttpServletRequest) request).getSession()
                        .getAttribute(Account.ACCOUNT_SESSION_KEY)) {
            ((HttpServletResponse) response)
                    .sendRedirect(((HttpServletRequest) request)
                            .getContextPath() + "/error.jsp?desc=UnLogin");
            return;
        }

        filter.doFilter(request, response);
    }

    public void init(FilterConfig config) throws ServletException {}
}