java WEB 登陆拦截器

package com.community.filter; import java.io.IOException; import java.io.PrintWriter; import java.util.ArrayList; import java.util.List; 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; public class LoginFilter implements Filter{ public static List<String> pattenURL = new ArrayList<String>(); @Override public void destroy() { // TODO Auto-generated method stub } public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { HttpServletRequest httpRequest = (HttpServletRequest) request; HttpServletResponse httpResponse = (HttpServletResponse) response; HttpSession session = httpRequest.getSession(); // 登陆url String loginUrl = httpRequest.getContextPath() + "/login.htm"; String url = httpRequest.getRequestURI().toString(); /* * 注：在pattenURL中的全部不拦截 * url.indexOf(urlStr) > -1 表示urlStr在url中出现过，出现就不拦截 * */ for (String urlStr : pattenURL) { if(url.indexOf(urlStr) > -1){ chain.doFilter(request, response); return; } } /* * 超时处理，ajax请求超时设置超时状态，页面请求超时则返回提示并重定向 * session.getAttribute("")是获取到登录人的session信息 * */ if (session.getAttribute("activeUser") == null) { // 判断是否为ajax请求 if (httpRequest.getHeader("x-requested-with") != null && httpRequest.getHeader("x-requested-with").equalsIgnoreCase("XMLHttpRequest")) { httpResponse.addHeader("sessionstatus", "timeOut"); //返回超时标识 httpResponse.addHeader("loginPath", loginUrl);// 返回url chain.doFilter(request, response);// 不可少，否则请求会出错 } else { //alert('会话过期,请重新登录'); String str = "<script language='javascript'>" + "window.top.location.href='" + loginUrl + "';</script>"; response.setContentType("text/html;charset=UTF-8");// 解决中文乱码 try { PrintWriter writer = response.getWriter(); writer.write(str); writer.flush(); writer.close(); } catch (Exception e) { e.printStackTrace(); } } } else { chain.doFilter(request, response); } } /* * 在pattenURL中的全部不拦截，所以上面会使用：path.indexOf(urlStr) > -1 * */ @Override public void init(FilterConfig arg0) throws ServletException { pattenURL.add("loginAction.htm");//登录方法 pattenURL.add("login.jsp");//登录页面 pattenURL.add("login.htm");//登录页面之一 // pattenURL.add("updateOPpassword.do");//修改密码方法 pattenURL.add("css");//css pattenURL.add("image");//image pattenURL.add("js");//js pattenURL.add("fonts");//fonts pattenURL.add("png"); } } 以上代码可以解决登陆的拦截 其中最后的init里面的参数 pattenURL是一个集合，已经在上面声明了成员变量，这里的参数也可以在WEB.XML里面进行配置。