cookies的应用

@Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //解决中文乱码
        req.setCharacterEncoding("utf-8");
        resp.setCharacterEncoding("utf-8");

        PrintWriter out= resp.getWriter();

        //Cookie,服务器从浏览器获取
        Cookie[] cookies = req.getCookies();

        //判断Cookie是否存在
        if (cookies!=null){
            out.write("你已经访问过该网站");
        }else{
            out.write("这是您第一次访问网站");
        }

        //服务器发给浏览器一个Cookie
        Cookie cookie = new Cookie("name", "张某人");

        resp.addCookie(cookie);
    }

 

 设置cookie的有效时间，当超过时间，cookie失效！！！

//设置cookie的有效时间
cookie.setMaxAge(60);