Cookie的一些用法

package com.stono.servlet.listenerorder;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class TestCookieServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        Cookie cookie = new Cookie("c1", "c1");
        cookie.setMaxAge(30 * 60);
        // 如果设置MaxAge为0，会导致Cookie立刻失效，在第二次访问的时候就已经没有Request Cookie了；
        // cookie.setMaxAge(0);
        // 进行添加之后，在ChromeDeveloperTools中可以看到Response Cookies；进行其他页面的请求，可以看到Request Cookies;
        resp.addCookie(cookie);
        Cookie[] cookies = req.getCookies();
        // 第一次输出1，只有JSESSIONID，第二次输出2，还有c1
        System.out.println(cookies.length);
        PrintWriter writer = resp.getWriter();
        writer.println("com.stono.servlet.listenerorder.TestCookieServlet.doGet(HttpServletRequest, HttpServletResponse)");
    }
}