标签:index res 用户信息 设置 exce 统一 发送 .com 包含
过滤器,其实就是对客户端发出来的请求进行过滤,浏览器发出,然后服务器用Servelt处理。在中间就可以过滤,起到的是拦截的作用。
不仅仅作用于客户端请求,而且过滤服务器响应
作用:
创建:部署到服务器,则初始化,创建
销毁:服务器停止则销毁
思路:
public class LoginServlet extends HttpServlet { protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { try { String username = request.getParameter("username"); String password = request.getParameter("password"); String autologin = request.getParameter("autologin");//on System.out.println(username+":"+password+":"+autologin); //校验用户名密码 UserBean user = new UserBean(); user.setUsername(username); user.setPassword(password); UserDao dao = new UserDaoImpl(); UserBean userBean = dao.Login(user); if(userBean!=null){ //页面提交上来的时候是否选择了自动登录 if("on".equals(autologin)){ Cookie cookie = new Cookie("auto_login", username+"#"+password ); cookie.setMaxAge(60*60*24*7);//7天有效期 cookie.setPath(request.getContextPath());//应用名字 response.addCookie(cookie); } //成功了,进入首页 request.getSession().setAttribute("userBean", userBean); response.sendRedirect("index.jsp"); }else{ //登录失败 request.getRequestDispatcher("login.jsp").forward(request, response); } } catch (SQLException e) { e.printStackTrace(); } }
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
思路:
public class AutoLoginFilter implements Filter { public void destroy() { } public void doFilter(ServletRequest req, ServletResponse response, FilterChain chain) throws IOException, ServletException { try { HttpServletRequest request = (HttpServletRequest) req; //先判断session中是否还有userBean,如果有,当前会话还是有效的 UserBean userBean = (UserBean) request.getSession().getAttribute("userBean"); if(userBean!=null){ //如果session有效,放行,此时页面有session信息,登录成功显示欢迎您,${userBean.username } chain.doFilter(request, response); }else{ //此时session失效,比如说关闭浏览器,第二次打开,此时看Cookie //1 取出Cookie, Cookie[] cookies = request.getCookies(); //2 找出需要的cookie Cookie cookie = CookieUtil.findCookie(cookies, "auto_login"); if(cookie==null){ //表明第一次登录,放行 chain.doFilter(request, response); }else{ //表明不是第一次,取出Cookie中的值,完成登录 String value = cookie.getValue(); String username = value.split("#")[0]; String password = value.split("#")[1]; System.out.println(username+":"+password); UserBean user = new UserBean(); user.setUsername(username); user.setPassword(password); UserDao dao = new UserDaoImpl(); userBean = dao.Login(user); //使用Session存一下这个值,方便下一次未过期前还可以用 request.getSession().setAttribute("userBean", userBean); chain.doFilter(request, response); } } } catch (Exception e) { e.printStackTrace(); //出现异常,也放行 chain.doFilter(req, response); } } public void init(FilterConfig fConfig) throws ServletException { System.out.println("Filter初始化了"); } }
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> 这是首页, <c:if test="${not empty userBean }"> 欢迎您,${userBean.username } </c:if> <c:if test="${ empty userBean }"> 您好,请登录! </c:if> </body> </html>
一、
标签:index res 用户信息 设置 exce 统一 发送 .com 包含
原文地址:https://www.cnblogs.com/ltfxy/p/10257642.html