java登录拦截Filter

<filter-mapping>
        <filter-name>SessionFilter</filter-name>
        <url-pattern>/*</url-pattern>
        <dispatcher>REQUEST</dispatcher>
    </filter-mapping>
<filter>
    <filter-name>SessionFilter</filter-name>
    <!--拦截类 -->
    <filter-class>com.skin.generate.user.UserLoginFilter</filter-class>
    <init-param>
        <param-name>loginUrl</param-name>
        <param-value>/finder/login.html</param-value>
    </init-param>
    <!--配置参数 比如不拦截的路径 -->
    <init-param>
        <param-name>excludes</param-name>
        <param-value>
            /register.html,
            /resource/**/*,
            /note/**/*
        </param-value>
    </init-param>
</filter> 

packagecom.skin.generate.user;
importjava.io.IOException;
importjavax.servlet.Filter;
importjavax.servlet.FilterChain;
importjavax.servlet.FilterConfig;
importjavax.servlet.ServletException;
importjavax.servlet.ServletRequest;
importjavax.servlet.ServletResponse;
importjavax.servlet.http.Cookie;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;
importjavax.servlet.http.HttpSession;
importcom.skin.finder.security.UserSession;
importcom.skin.finder.web.util.Client;
importcom.skin.finder.web.util.CookieUtil;
importcom.skin.generate.entity.User;
public class UserLoginFilter implementsFilter {
/*
     * String nofilter; String nofilterFiles[]; String sendRedirect;
     */
    public voiddestroy() {
    }
    public voiddoFilter(ServletRequest req, ServletResponse res,
            FilterChain chain) throwsIOException, ServletException {
        HttpServletRequest request =(HttpServletRequest) req;
        HttpServletResponse response =(HttpServletResponse) res;
        String path =request.getServletPath();
        String url =request.getRequestURI();
        //如果不需要过滤的静态文件，直接放行
        if (path.endsWith(".css") || path.endsWith(".js")
                || path.endsWith("Login.html") 
                || url.indexOf("resource") > 0 || url.indexOf("note") > 0
                || url.endsWith("login.jsp") || path.endsWith(".gif")
                || path.endsWith(".ico")) {
            chain.doFilter(request, response);
            return;
        } else{
            if(checkUser(request, response)) {
                chain.doFilter(request, response);//如果用户已经登录，就放行
                return;
            } else{
                //没有登录，重定向到登录页面
                String contextPath =getContextPath(request);
                response.sendRedirect(contextPath+ "/template/finder/login.jsp");
                return;
            }
        }
    }
    protectedString getContextPath(HttpServletRequest request) {
        String contextPath =request.getContextPath();
        if ((contextPath == null) || (contextPath.equals("/"))) {
            return "";
        }
        returncontextPath;
    }
    private booleanisInArray(String path, String nofilterFiles[]) {
        for (int i = 0; i < nofilterFiles.length; i++) {
            String nofilterFile =nofilterFiles[i];
            if(nofilterFile.equals(path)) {
                return true;
            }
        }
        return false;
    }
    private booleancheckUser(HttpServletRequest request,
            HttpServletResponse response) throwsIOException {
        //1.判断cookie 是否存在
        Cookie cookie =CookieUtil.getCookie(request, Client.COOKIE_NAME);
        if(cookie ==null){
            return false;
        }
        //2.校验session
        HttpSession session = request.getSession(false);//如果不存在返回空
        if (session == null) {
            return false;
        }
        //3.校验登录用户
        Object obj =session.getAttribute(SessionUtils.USER_NAME);
        if (obj == null) {
            return false;
        }
        return true;
    }
    public void init(FilterConfig config) throwsServletException {
        /*
         * nofilter = config.getInitParameter("excludes"); 
         * nofilterFiles =nofilter.split(","); sendRedirect =
         * config.getInitParameter("loginUrl");
         */
        //System.out.println(Arrays.asList(nofilterFiles));
}
}