//读取所以的cookie信息再选中我们想要的cookie Cookie []ck=request.getCookies(); for (int i = 0; i < ck.length; i++) { Cookie ck1=ck[i];
out.println(\的名字是：\的值是：
\
} System.out.println(ck.length); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doGet(request, response); } }
Cookie可以用来做什么？
1可以保存上次登陆的信息
2保存用户名和密码，不用我们再次输入
3记录用户访问网站的一些喜好（比如：网页背景色，有无背景音乐） 4网站的个性化（定制网站的服务，内容）
Cookie小总结：
1 cookie是服务器创建的 2 cookie保存在浏览器端
3 cookie的生命周期可以使用setMaxAge(3600)来设置，如果不设置，那么只要关闭浏览器，cookie就消失了
4 cookie可以被多个浏览器共享
5 cookie可以看成是一个表格
6 如果我们创建的cookie重名会怎么办？ 如果重名了就会替换掉原来的cookie package com.xueye.testCookie;
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 CreateCookie2 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType(\ request.setCharacterEncoding(\ PrintWriter out = response.getWriter(); Cookie ck=new Cookie(\ Cookie ck2=new Cookie(\ ck.setMaxAge(3600); ck2.setMaxAge(3600); response.addCookie(ck); response.addCookie(ck2); out.println(\第二个cookie已经创建\ } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
}
this.doGet(request, response);
7 一个web应用可以保存多个cookie
Cookie实际运用
1 显示用户上次登陆的时间
package com.xueye.testCookie.yunyong;
import java.io.IOException; import java.io.PrintWriter;
import java.text.SimpleDateFormat;
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 Servlet1 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType(\ request.setCharacterEncoding(\ PrintWriter out = response.getWriter(); //获取cookie //假设我们保存的上次登陆的时间是：cookie \ //这里我们要考虑第一次登陆的情况，如果是第一次登陆的话，我们提示欢迎第一次登陆 Cookie[]ck=request.getCookies(); boolean b=false; if(ck!=null){ for (Cookie cookie : ck) { //取出名字 String name=cookie.getName(); if(\ //显示
}
}
out.println(\你上次登陆的时间是：\ //更新时间 SimpleDateFormat sdf=new SimpleDateFormat(\ String date=sdf.format(new java.util.Date()); cookie.setValue(date); cookie.setMaxAge(7*24*3600); response.addCookie(cookie); b=true; break; } } }
if(b==false){ }
//没有找到我们的cookie
SimpleDateFormat sdf=new SimpleDateFormat(\String date=sdf.format(new java.util.Date()); out.println(\你是第一次登陆...\
Cookie ck1=new Cookie(\ck1.setMaxAge(7*24*3600); response.addCookie(ck1);
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { }
this.doGet(request, response);
2保存用户登陆的用户名和密码，在用户下次登陆的时候不用再次填写了 1Login
package com.xueye.testCookie;
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 Login extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType(\ request.setCharacterEncoding(\ PrintWriter out = response.getWriter(); //从cookie中选中keep cookie String id=\ Cookie []ck=request.getCookies(); if(ck!=null){ for (Cookie cookie : ck) { if(cookie.getName().equals(\ id=cookie.getValue(); } } }
out.println(\用户登录\
out.println(\
out.println(\用户名:
\ out.println(\type='checkbox' value='keep' name='iskeep'>是否保存登陆信息
\ out.println(\type='checkbox' value='nokeep' name='iskeep'>不保存登陆信息
\ out.println(\登录'>\ out.println(\ } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doGet(request, response); }