/** * The Apache License 2.0 Copyright (c) 2017 Zhang Peng */ package io.github.dunwu.javaee.session; import java.io.IOException; import java.io.PrintWriter; import java.text.SimpleDateFormat; import java.util.Date; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; /** * @author <a href="mailto:[email protected]">Zhang Peng</a> * @since 2017/3/26. */ @WebServlet("/servlet/SessionTrackServlet") public class SessionTrackServlet extends HttpServlet { private static final long serialVersionUID = 1L; public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 如果不存在 session 会话,则创建一个 session 对象 HttpSession session = request.getSession(true); // 获取 session 创建时间 Date createTime = new Date(session.getCreationTime()); // 获取该网页的最后一次访问时间 Date lastAccessTime = new Date(session.getLastAccessedTime()); // 设置日期输出的格式 SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); String title = "Servlet Session 实例"; Integer visitCount = new Integer(0); String visitCountKey = new String("visitCount"); String userIDKey = new String("userID"); String userID = new String("admin"); // 检查网页上是否有新的访问者 if (session.isNew()) { session.setAttribute(userIDKey, userID); } else { visitCount = (Integer) session.getAttribute(visitCountKey); visitCount = visitCount + 1; userID = (String) session.getAttribute(userIDKey); } session.setAttribute(visitCountKey, visitCount); // 设置响应内容类型 response.setContentType("text/html;charset=UTF-8"); PrintWriter out = response.getWriter(); String docType = "<!DOCTYPE html>\n"; out.println(docType + "<html>\n" + "<head><title>" + title + "</title></head>\n" + "<body bgcolor=\"#f0f0f0\">\n" + "<h1 align=\"center\">" + title + "</h1>\n" + "<h2 align=\"center\">Session 信息</h2>\n" + "<table border=\"1\" align=\"center\">\n" + "<tr bgcolor=\"#949494\">\n" + " <th>Session 信息</th><th>值</th></tr>\n" + "<tr>\n" + " <td>id</td>\n" + " <td>" + session.getId() + "</td></tr>\n" + "<tr>\n" + " <td>创建时间</td>\n" + " <td>" + df.format(createTime) + " </td></tr>\n" + "<tr>\n" + " <td>最后访问时间</td>\n" + " <td>" + df.format(lastAccessTime) + " </td></tr>\n" + "<tr>\n" + " <td>用户 ID</td>\n" + " <td>" + userID + " </td></tr>\n" + "<tr>\n" + " <td>访问统计:</td>\n" + " <td>" + visitCount + "</td></tr>\n" + "</table>\n" + "</body></html>"); } }