Cookie

Cookie

浏览器利用Cookie缓存数据 服务器往浏览器写入
浏览器在发送请求的时候 会把Cookie发送给服务器哪个服务器发送的Cookie 浏览器就发送给谁)

创建Cookie

在Servlet 创建Cookie 响应给浏览器

@WebServlet("/Test")
public class Test extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        Cookie cookie = new Cookie("key", "Message");
        cookie.setMaxAge(3600);//设置Cookie的存活时间 单位是 秒
        resp.addCookie(cookie);
        System.out.println("hello");
    }
}

浏览器请求 访问

获取Cooke

@WebServlet("/GetCookie")
public class GetCookie extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // Http请求获取cookie 的值
        Cookie[] cookies = req.getCookies();
        for (Cookie cookie : cookies) {
            if ("key".equals(cookie.getName())) {
                System.out.println(cookie.getValue());
            }
        }
    }
}