Servlet ---- cookie & session
2022/1/10 6:05:46
本文主要是介绍Servlet ---- cookie & session,对大家解决编程问题具有一定的参考价值,需要的程序猿们随着小编来一起学习吧!
Cookie 属性 和 构造
Cookie的添加 和 获取
记录最后访问时间
@WebServlet(name = "ServletDemo25", value = "/ServletDemo25") public class ServletDemo25 extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=UTF-8"); PrintWriter pw = response.getWriter(); pw.write("欢迎访问本网站,您的最后访问时间为:<br>"); //创建Cookie对象,记录最后访问时间 Cookie cookie = new Cookie("time", System.currentTimeMillis() + ""); //设置最大存活时间 1h cookie.setMaxAge(3600); //将cookie对象添加到客户端 response.addCookie(cookie); //获取cookie Cookie[] arr = request.getCookies(); for (Cookie c : arr){ if ("time".equals(c.getName())){ //获取cookie对象中的value,进行写出 String value = c.getValue(); SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); pw.write(sdf.format(new Date(Long.parseLong(value)))); } } } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request,response); } }
Cookie 使用细节
HttpSession
HttpSession实现类对象获取
@WebServlet(name = "ServletDemo26", value = "/ServletDemo26") public class ServletDemo26 extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //获取参数值 String username = request.getParameter("username"); //获取session对象 HttpSession session = request.getSession(); System.out.println(session); System.out.println(session.getId()); //设置参数到session中 session.setAttribute("username",username); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request,response); } }
@WebServlet(name = "ServletDemo27", value = "/ServletDemo27") public class ServletDemo27 extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //获取session对象 HttpSession session = request.getSession(); System.out.println(session); System.out.println(session.getId()); //获取共享数据 Object username = session.getAttribute("username"); //响应 response.getWriter().write(username + ""); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request,response); } }
cookie禁用
@Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //获取参数值 String username = request.getParameter("username"); //获取session对象 HttpSession se1 = request.getSession(false); HttpSession session = request.getSession(); System.out.println(session); System.out.println(session.getId()); //设置参数到session中 session.setAttribute("username",username); if (session != se1){ response.setContentType("text/heml;charset=UTF-8"); response.getWriter().write("为了不影响正常使用,请不要禁用浏览器的Cookie"); } }
//实现url重写 相当于在地址栏后面拼接了jsessionid response.getWriter().write("<a href='" + response.encodeURL("http://localhost/8080/session/servletDemo") + "'></a>");
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