第一步：建工程 建包建servlet类

第二步：编写servlet类

public class cookie extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //解决中文乱码
        req.setCharacterEncoding("utf8");
        resp.setCharacterEncoding("utf8");
        resp.setContentType("text/html");
        PrintWriter out = resp.getWriter();
        //Cookie 服务器从客户端获取
        Cookie[] cookies = req.getCookies();
        if (cookies != null) {
            out.write("您上次所访问的时间：\n");
            //遍历cookies
            for (int i = 0; i <cookies.length ; i++) {
                if(cookies[i].getName().equals("time")){
                    String timeStr = cookies[i].getValue();
                    //转换为时间 
                    long time = Long.parseLong(timeStr);
                    Date date = new Date(time);
                    out.write(date.toLocaleString());
                }
            }
        }else{
            out.write("第一次见面 请多多关照");
        }
        //服务器给客户端响应一个Cookie
        Cookie cookie = new Cookie("time", String.valueOf(System.currentTimeMillis()));
        resp.addCookie(cookie);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

第三步：在web.xml中注册servlet

<!--    注册servlet-->
    <servlet>
        <servlet-name>cookie</servlet-name>
        <servlet-class>com.csnz.servlet.cookie</servlet-class>
    </servlet>
<!--    配置servlet的映射-->
    <servlet-mapping>
        <servlet-name>cookie</servlet-name>
        <url-pattern>/see</url-pattern>
    </servlet-mapping>

第四步：配置tomcat 启动服务器访问

第一次访问

cookie已经存进去了

此时刷新页面