Java學習總結048--Cookie

構造器 ：

Cookie cookie = new Cookie(String name,String value);
Cookie cookie = new Cookie(String name,String value);
Cookie cookie = new Cookie(String name,String value);

服務器響應cookie給客戶端

Response.addCookie(Cookie);
Response.addCookie(Cookie);
Response.addCookie(Cookie);

服務查看用戶帶來的請求是否有cookie

Cookie[] cookies = Request.getCookie();
//可以使用cookie來驗證用戶是否來過
//判斷cookies是否爲空，然後遍歷即可
Cookie.getName();
Cookie.getValue();

cookie測試用戶是否來過

public class CookieTest extends HttpServlet {
    boolean flag = false;

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);
    }
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //解決亂碼問題：
        request.setCharacterEncoding("UTF-8");
        response.setCharacterEncoding("UTF-8");
        //檢查請求的人是否帶了Cookie
        //通過用戶的請求，檢查它是否有cookie
        Cookie[] cookies = request.getCookies();
        System.out.println("cookie:"+cookies);
        if (flag){//如果flag是真，來過
            if (cookies!=null){//你有cookie
                for (int i = 0; i < cookies.length ; i++) {
                    Cookie cookie = cookies[i];
                    if (cookie.getName().equals("lastLoginTime")){
                        response.getWriter().println("你上一次來的時間爲："+cookie.getValue());
                        System.out.println("刷新了cookie");
                    }
                }
            }
        }else { //如果flag是真，沒來過
            response.getWriter().println("你是第一次來，還想要會員套餐");
            System.out.println("給該用戶一個cookie");
        }

        //建立一個cookie
        Cookie cookie = new Cookie("lastLoginTime",System.currentTimeMillis()+"");

        //設置cookie保存的時間 //cookie.setMaxAge();
        //把這個cookie發給客戶端
        response.addCookie(cookie);
        //response.addCookie(new Cookie("lastLoginTime",System.currentTimeMillis()+""));
        flag = true;
    }
}