建立Cookie

建立一個繼承自HttpServlet的類(記得註冊)，並且重寫doGet方法，程式碼如下：

package com.haya.web;

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

public class MyCookie extends HttpServlet {
    public MyCookie() {
        super();
    }
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		//...
    }
}

接下來完善doGet方法，程式碼如下：

protected void doGet(HttpServletRequest req,
 
 HttpServletResponse resp) throws ServletException, IOException {
    //建立Cookie
    Cookie cookie1 = new Cookie("test","haha");
    Cookie cookie2 = new Cookie("test2", "lala");
    /*
        *設定Cookie的有效時長，單位(秒)，
        * 當引數大於0,將Cookie快取到本地硬碟上
        * 當引數等於0，Cookie一旦設定立馬失效
        * 當Cookie小於0，將Cookie快取到瀏覽器中
    */
 

    cookie1.setMaxAge(60*60*24);
    cookie2.setMaxAge(60*60*24);
    //繫結路徑
    cookie1.setPath(req.getContextPath()+"/cookie1");
    cookie2.setPath(req.getContextPath()+"/cookie2");
    //向響應中新增Cookie
    resp.addCookie(cookie1);
    resp.addCookie(cookie2);

}

此時訪問指定路徑，再用瀏覽器自帶的工具檢視就能看到Cookie。

Servlet讀取Cookie

按照上述方法建立完Cookie後，再建立另一個Servlet(記得註冊)，繼承自HttpServlet，重寫doGet()方法：

@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
    throws ServletException, IOException {
    Cookie[] cookies = req.getCookies();
    for (Cookie c: cookies) {
        System.out.println(c.getName()+":"+c.getValue());
    }
}

此時先訪問Cookie註冊時的url，再訪問這個Servlet註冊的url，如果ide的控制檯輸出cookie的資訊,就說明訪問成功。