Cookie_原理分析以及发送多个Cookie

Cookie_原理分析

实现原理：

基于响应头set-cookie和请求头cookie实现

发送多个Cookie

cookie的细节：

　　1.一次可不可以发送多个cookie？

　　　　可以

　　　　　　可以创建多个Cookie对象，使用response调用多次addCookie方法发送Cookie即可

发送cookie：

@WebServlet(name = "CookieDemo3", value = "/CookieDemo3")
public class CookieDemo3 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.创建Cookie对象
        Cookie c1 = new Cookie("msg", "hello");
        Cookie c2 = new Cookie("msg", "zhangsan");

        //2.发送Cookie
        response.addCookie(c1);
        response.addCookie(c2);
    }
}

获取cookie：

@WebServlet(name = "CookieDemo2", value = "/CookieDemo2")
public class CookieDemo2 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //3.获取Cookie
        Cookie[] cookies = request.getCookies();
        //获取数据，遍历Cookie
        if (cookies != null){
            for (Cookie cookie : cookies) {
                String name = cookie.getName();
                String value = cookie.getValue();
                System.out.println(name+":"+value);
            }
        }
    }
}

　　2.cookie在浏览器中保存多长时间？

　　3.cookie能不能存中文？

　　4.cookie获取范围多大？