使用cookie实现永久登陆
1，在cookie里面保存账号密码然后和数据库核对（由于我没有使用数据库，就不用了
2，在cookie里面保存时间戳和账号使用加密解密（我也没有使用时间戳
思路，request.getParameter("account");,获得账号，存入cookie，加入时间戳重定制网页内容
由于重定制的关系，这个时候我们不能用getParameter了，只能在cookie获得资料
原码
<%@page contentType="text/html"%> <%@page pageEncoding="UTF-8"%> <%!private static final String KEY = "huanggabin"; public final static String getPassword(String a) { return a; }%> <% request.setCharacterEncoding("UTF-8"); response.setCharacterEncoding("UTF-8"); String action = request.getParameter("action"); if ("login".equals(action)) { String account = request.getParameter("account"); String account2 = request.getParameter("account"); System.out.println(account2); String password = request.getParameter("password"); int timeout = Integer.parseInt(request.getParameter("timeout")); String ssid = getPassword(account + KEY); Cookie accountCookie = new Cookie("account", account); accountCookie.setMaxAge(timeout); Cookie ssidCookie = new Cookie("ssid", ssid); ssidCookie.setMaxAge(timeout); response.addCookie(accountCookie); response.addCookie(ssidCookie); response.sendRedirect(request.getRequestURI() + "?" + System.currentTimeMillis()); return; } else if ("logout".equals(action)) { Cookie accountCookie = new Cookie("account", ""); accountCookie.setMaxAge(0); Cookie ssidCookie = new Cookie("ssid", ""); ssidCookie.setMaxAge(0); response.addCookie(accountCookie); response.addCookie(ssidCookie); response.sendRedirect(request.getRequestURI() + "?" + System.currentTimeMillis()); return; } boolean login = false; String account = null; String ssid = null; if (request.getCookies() != null) { for (Cookie cookie : request.getCookies()) { if (cookie.getName().equals("account")) { account = cookie.getValue(); } if (cookie.getName().equals("ssid")) { ssid = cookie.getValue(); } } } if (account != null && ssid != null) { login = ssid.equals(getPassword(account + KEY)); } %> <% String account2 = request.getParameter("account"); //System.out.println(account2); %> <!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>JSP Page</title> <script> alert(document.cookie); </script> </head> <body> <%=login ? "欢迎回来" : "请先登录"%><br /> <% if (login) { %> 欢迎你!!!,<%=account%> <a href="${pageContext.request.requestURI}?action=logout">注销</a> <% } else { %> <form action="${pageContext.request.requestURI}?action=login" method='post'> 账号：<input type="text" name="account"><br /> 密码: <input type="text" name="password"><br /> 有效期： <input type="radio" name="timeout" value="-1">关闭浏览器失效<br /> <input type="radio" name="timeout" value="<%=30 * 24 * 60 * 60%>">30天有效<br /> <input type="radio" name="timeout" value="<%=Integer.MAX_VALUE%>">永久有效<br /> <input type="submit" value="登陆 " class="button"> </form> <% } %> </body> </html>