设计要求：
默认首页为“pages/index.html”，有生成32位大写字母（A~F）和数字（0~9）混合的随机字符串功能，有设置Cookie，读取Cookie的功能。
前端HTML页面（index.html）：
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width,minimum-scale=1.0,maximum-scale=1.0,user-scalable=no" /> <title>Powered By Leisureeen</title> <script src="./js/req.js"></script> <script type="text/javascript"> function b_req(index) { var idV = document.getElementById("id").value; var result = document.getElementById("res"); if (index == 1) Request("action.do", "post", "index=" + index + "&id=" + idV, result); else Request("action.do", "post", "index=" + index, result); } </script> </head> <body bgcolor="AADDFF"> <div align="center" style="line-height: 30px;"> <input type="text" id="id" maxlength="8" value=""> <br> <input type="submit" value="Load Cookie" onclick="b_req(0)"> <input type="submit" value="Store Cookie" onclick="b_req(1)"> <input type="submit" value="UUID" onclick="b_req(2)"> <br> <div id="res" style="color: red"></div> </div> </body> </html>
req.js文件：
function Request(url, action, json, result) { var httpRequest = new XMLHttpRequest(); httpRequest.open(action, url, true); httpRequest.setRequestHeader("Content-type", "application/x-www-form-urlencoded"); httpRequest.send(json); httpRequest.onreadystatechange = function() { if (httpRequest.readyState == 4 && httpRequest.status == 200) result.innerHTML = httpRequest.responseText; }; }
web.xml文件：
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0"> <display-name>TestCookie</display-name> <!-- ALL functions 1 welcome-file 2 UUID 3 Cookie --> <welcome-file-list> <welcome-file>pages/index.html</welcome-file> <welcome-file>index.html</welcome-file> <welcome-file>index.htm</welcome-file> <welcome-file>index.jsp</welcome-file> <welcome-file>default.html</welcome-file> <welcome-file>default.htm</welcome-file> <welcome-file>default.jsp</welcome-file> </welcome-file-list> <servlet> <servlet-name>servlet</servlet-name> <servlet-class>controller.Servlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>servlet</servlet-name> <url-pattern>/action.do</url-pattern> </servlet-mapping> </web-app>
后端收发数据Java类（Servlet.java）：
package controller; import java.io.IOException; import java.util.UUID; 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 Servlet extends HttpServlet{ protected void doPost(HttpServletRequest req,HttpServletResponse resp) throws ServletException, IOException{ req.setCharacterEncoding("utf-8"); String index=req.getParameter("index"); // resp.setContentType("application/json; charset=utf-8"); resp.setContentType("text/html;charset=utf-8"); if(index.equals("0")){ Cookie[] cookies=req.getCookies(); if(cookies!=null) for(Cookie cookie: cookies) if(cookie.getName().equals("id")) resp.getWriter().print("id is "+cookie.getValue()); }else if(index.equals("1")){ String id=req.getParameter("id"); Cookie cookie=new Cookie("id",id); resp.addCookie(cookie); resp.getWriter().print("AddCookie Success!"); }else if(index.equals("2")){ String uuid=UUID.randomUUID().toString().replace("-","").toUpperCase(); resp.getWriter().print(uuid); }else resp.getWriter().print("index error!"); } }