今天学习了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.runoob.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("</body>"); out.println("</html>"); } /** * @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); } }