Servlet 教程 之 Servlet Cookie 处理 7
Servlet Cookie 处理
通过 Servlet 删除 Cookie
删除 Cookie 是非常简单的。如果您想删除一个 cookie，那么您只需要按照以下三个步骤进行：
读取一个现有的 cookie，并把它存储在 Cookie 对象中。
使用 setMaxAge() 方法设置 cookie 的年龄为零，来删除现有的 cookie。
把这个 cookie 添加到响应头。
实例
下面的例子将删除现有的名为 "url" 的 cookie，当您下次运行 ReadCookies 的 Servlet 时，它会返回 url 为 null。
package com.baidu.test;
import java.io.IOException;
import java.io.PrintWriter;
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;
/**
Servlet implementation class DeleteCookies
*/
@WebServlet("/DeleteCookies")
public class DeleteCookies extends HttpServlet {
private static final long serialVersionUID = 1L;/**
@see HttpServlet#HttpServlet()
*/
public DeleteCookies() {
super();
// TODO Auto-generated constructor stub
}/**
@see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
Cookie cookie = null;
Cookie[] cookies = null;
// 获取与该域相关的 Cookie 的数组
cookies = request.getCookies();// 设置响应内容类型response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
String title = "删除 Cookie 实例";
String docType = "<!DOCTYPE html>\n";
out.println(docType +"<html>\n" + "<head><title>" + title + "</title></head>\n" + "<body bgcolor=\"#f0f0f0\">\n" );if( cookies != null ){
out.println("<h2>Cookie 名称和值</h2>"); for (int i = 0; i < cookies.length; i++){ cookie = cookies[i]; if((cookie.getName( )).compareTo("url") == 0 ){ cookie.setMaxAge(0); response.addCookie(cookie); out.print("已删除的 cookie：" + cookie.getName( ) + "<br/>"); } out.print("名称：" + cookie.getName( ) + "，"); out.print("值：" + cookie.getValue( )+" <br/>"); }}else{
out.println( "<h2 class=\"tutheader\">No Cookie founds</h2>");}
out.println("");
out.println("");
}/**
- @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
编译上面的 Servlet DeleteCookies，并在 web.xml 文件中创建适当的条目。现在运行 http://localhost:8080/TomcatTest/DeleteCookies
