java Servlet中使用Cookie记录浏览器客户端访问时间

@WebServlet("/accessTimeServlet")
public class AccessTimeServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 设置 ContentType
        response.setContentType("text/html;charset=utf-8");
        // 获取Cookies
        Cookie[] cookies = request.getCookies();
        boolean flag = false;
        if (cookies != null && cookies.length > 0) {
            for (Cookie cookie : cookies) {
                if (cookie.getName().equals("lastTime")) {
                    flag = true;
                    // 定义时间
                    String date = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date());
                    // 通过url解码并输出至窗口
                    response.getWriter().write("欢迎回来，您上次访问时间为" + URLDecoder.decode(cookie.getValue(), "utf-8"));
                    // 因cookie无法存储空格,所以通过url编码添加
                    cookie.setValue(URLEncoder.encode(date, "utf-8"));
                    // 设置cookie蠢货时间
                    cookie.setMaxAge(30 * 24 * 60 * 60);
                    // 添加cookie 值
                    response.addCookie(cookie);
                    break;
                }
            }
        }

        if (cookies == null || cookies.length < 1 || flag == false) {
            response.getWriter().write("您好，欢迎首次访问！");
            // 定义时间
            String date = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date());
            // 创建cookie
            Cookie timeCookie = new Cookie("lastTime", URLEncoder.encode(date, "utf-8"));
            // 添加进cookies
            response.addCookie(timeCookie);
        }
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }
}