Cookie session technology-quick start

table of Contents

Cookie：

 1. Concept: Client session data technology, save data to the client.

  2. Quick start:

3. Implementation principle:

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Cookie：

 1. Concept: Client session data technology, save data to the client.

 

  2. Quick start:

 Steps for usage:

        ①Create Cookie object and bind data

        new Cookie(String name,String value)

        ②Send Cookie Object

        response.addCookie(Cookie cookie)

        ③Get Cookie, get data

        Cookie[] request.getCookies()

 

CookieDemo1 class:

package jason.lh.cookie;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;


//Cookie快速入门

@WebServlet("/CookieDemo1")
public class CookieDemo1 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

         //①创建Cookie对象
        Cookie c = new Cookie("msg","Hello");
        //②发送Cookie
        response.addCookie(c);
        //

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }
}

CookieDemo2 class:

package jason.lh.cookie;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;


//Cookie快速入门

@WebServlet("/CookieDemo2")
public class CookieDemo2 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //③获取Cookie
        Cookie[] cs = request.getCookies();
        //④获取数据，遍历Cookies
        if (cs != null) {
            for (Cookie c : cs) {
                String name = c.getName();
                String value = c.getValue();
                System.out.println(name + ":" + value);
            }

        }
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws
            ServletException, IOException {
        this.doPost(request, response);
    }

}

Virtual directory bit /day16

Console output:

 

3. Implementation principle:

Implementation based on response set-cookie and request header cookie