会话 Cookie 和Session

1.Cookie  第一次发送请求显示"还没有数据...."

public class CookieDemo extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        //创建cookie 对象
        Cookie cookie = new Cookie("name", "ckang");
        Cookie cookie1 = new Cookie("email","[email protected]");
        // 发送cookie到浏览器
        response.addCookie(cookie);
        response.addCookie(cookie1);

        //获取从浏览器中请求中带来的cookie信息
        Cookie[] cookies = request.getCookies();
        if (null != cookies) {
            for(Cookie c : cookies){
                String name = c.getName();
                String value = c.getValue();
                System.out.println(name+":::"+value);
            }
        }else{
            System.out.println("cookie还没有数据...");
        }
    }
}

效果图:

2.Session