使用kaptcha生成驗證碼

時間 2019-11-20

標籤使用 kaptcha 生成驗證碼简体版

原文原文鏈接

　　kaptcha是一個簡單好用的驗證碼生成工具，經過配置，能夠本身定義驗證碼大小、顏色、顯示的字符等等。下面就來說一下如何使用kaptcha生成驗證碼以及在服務器端取出驗證碼進行校驗。javascript

1、搭建測試環境

1.一、建立Web測試項目

　　新建一個Web項目，並將kaptcha-2.3.2.jar放在項目的WEB-INF/lib目錄下，以下圖所示：html

1.二、在web.xml文件配置生成驗證碼的KaptchaServlet

　　KaptchaServlet的詳細配置以下：java

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <web-app version="2.5" 
 3     xmlns="http://java.sun.com/xml/ns/javaee" 
 4     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
 5     xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
 6     http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
 7   <welcome-file-list>
 8     <welcome-file>index.jsp</welcome-file>
 9   </welcome-file-list>
10   
11    <!-- kaptcha驗證碼配置 -->
12     <servlet>
13         <!-- 生成圖片的Servlet -->
14         <servlet-name>Kaptcha</servlet-name>
15         <servlet-class>com.google.code.kaptcha.servlet.KaptchaServlet</servlet-class>
16         
17         <!-- 是否有邊框-->
18         <init-param>
19             <param-name>kaptcha.border</param-name>
20             <param-value>no</param-value>
21         </init-param>    
22         <!-- 字體顏色 -->
23         <init-param>
24             <param-name>kaptcha.textproducer.font.color</param-name>
25             <param-value>red</param-value>
26         </init-param>
27         <!-- 圖片寬度 -->
28         <init-param>
29             <param-name>kaptcha.image.width</param-name>
30             <param-value>135</param-value>
31         </init-param>
32         <!-- 使用哪些字符生成驗證碼 -->
33         <init-param>
34             <param-name>kaptcha.textproducer.char.string</param-name>
35             <param-value>ACDEFHKPRSTWX345679</param-value>
36         </init-param>
37         <!-- 圖片高度 -->
38         <init-param>
39             <param-name>kaptcha.image.height</param-name>
40             <param-value>50</param-value>
41         </init-param>
42         <!-- 字體大小 -->
43         <init-param>
44             <param-name>kaptcha.textproducer.font.size</param-name>
45             <param-value>43</param-value>
46         </init-param>
47         <!-- 干擾線的顏色 -->
48         <init-param>
49             <param-name>kaptcha.noise.color</param-name>
50             <param-value>black</param-value>
51         </init-param>
52         <!-- 字符個數 -->
53         <init-param>
54             <param-name>kaptcha.textproducer.char.length</param-name>
55             <param-value>4</param-value>
56         </init-param>
57         <!-- 使用哪些字體 -->
58         <init-param>
59             <param-name>kaptcha.textproducer.font.names</param-name>
60             <param-value>Arial</param-value>
61         </init-param>        
62     </servlet>
63     <!-- 映射的url -->
64     <servlet-mapping>
65         <servlet-name>Kaptcha</servlet-name>
66         <url-pattern>/Kaptcha.jpg</url-pattern>
67     </servlet-mapping>
68 </web-app>

1.三、顯示生成的驗證碼

　　在頁面index.jsp顯示驗證碼jquery

 1 <%@ page language="java" pageEncoding="UTF-8"%>
 2 <!DOCTYPE HTML>
 3 <html>
 4   <head>
 5     <title>顯示KaptchaServlet生成的驗證碼</title>
 6     <script type="text/javascript" src="${pageContext.request.contextPath}/js/jquery-1.9.1.js"></script>
 7     <script type="text/javascript">
 8         //點擊切換驗證碼
 9         function changeVerifyCode(){
10             $("#yzmImg").attr("src","Kaptcha.jpg?"+Math.floor(Math.random()*100));
11         }
12         
13         //提交
14         function doSubmit() {
15             var verifyCodeValue = $("#verifyCode").val();
16             if(verifyCodeValue.replace(/\s/g,"") == "") {
17                 alert("請輸入驗證碼");
18             }else {
19                 //提交前先異步檢查驗證碼是否輸入正確
20                 var verifyUrl = "${pageContext.request.contextPath}/servlet/VerifyServlet?verifyCode="+verifyCodeValue;
21                 $.ajax({
22                     type:"GET",
23                     url:verifyUrl,
24                     success:function(returnData){
25                         if(returnData!="Y") {
26                             alert("請輸入正確的驗證碼！");
27                         }else {
28                             //驗證碼正確，進行提交操做
29                             alert("驗證碼輸入正確，提交表單");
30                         }
31                     },
32                     error:function(e){
33                         alert(e);
34                     }
35                 });
36             }
37         }
38     </script>
39   </head>
40   
41   <body>
42        <form>
43         <table>
44             <tr>
45                 <td>    
46                         請輸入驗證碼：
47                 </td>
48                 <td>
49                     <input type="text" name="verifyCode" id="verifyCode">
50                     <img src="Kaptcha.jpg" onclick="changeVerifyCode()" id="yzmImg" style="cursor: pointer;">
51                     <a href="javascript:void(0)" onclick="changeVerifyCode()">看不清，換一張</a>
52                 </td>
53             </tr>
54             <tr>
55                 <td>    
56                     &nbsp;
57                 </td>
58                 <td>
59                     <input type="button" value="提交" onclick="doSubmit()">
60                 </td>
61             </tr>
62         </table>
63     </form>    
64   </body>
65 </html>

　　運行效果以下圖所示：web

1.四、在服務器端驗證提交的驗證碼

　　用戶在form表單中提交了驗證碼以後，咱們會在服務器端進行驗證，編寫一個VerifyServlet，代碼以下：ajax

 1 /**
 2  * 
 3  */
 4 package me.gacl.web.controller;
 5 
 6 import java.io.IOException;
 7 import java.io.PrintWriter;
 8 
 9 import javax.servlet.ServletException;
10 import javax.servlet.http.HttpServlet;
11 import javax.servlet.http.HttpServletRequest;
12 import javax.servlet.http.HttpServletResponse;
13 
14 public class VerifyServlet extends HttpServlet {
15 
16     
17     public void doGet(HttpServletRequest request, HttpServletResponse response)
18             throws ServletException, IOException {
19 
20         response.setContentType("text/html;charaset=utf-8");
21         response.setHeader("pragma", "no-cache");
22         response.setHeader("cache-control", "no-cache");
23         PrintWriter out = null;
24         try {
25             //響應數據
26             String resultData;
27             //獲取傳過來的驗證碼
28             String verifyCode = request.getParameter("verifyCode");
29             System.out.println("verifyCode----"+verifyCode);
30             if(verifyCode=="") {
31                 resultData = "N";
32             }else {
33                 //獲取kaptcha生成存放在session中的驗證碼
34                 String kaptchaValue = (String) request.getSession().getAttribute(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);
35                 //比較輸入的驗證碼和實際生成的驗證碼是否相同
36                 if(kaptchaValue == null || kaptchaValue == ""||!verifyCode.equalsIgnoreCase(kaptchaValue)) {
37                     resultData = "N";
38                 }else {
39                     resultData = "Y";
40                 }
41             }
42             out = response.getWriter();
43             out.write(resultData);
44             out.flush();
45         }catch(Exception e) {
46             e.printStackTrace();
47         }finally {
48             if(out != null) {
49                 out.close();
50             }
51         }
52     }
53 }

　　在web.xml中註冊VerifyServlet服務器

1 <!-- 檢查驗證碼是否輸入正確 -->
2     <servlet>
3         <servlet-name>VerifyServlet</servlet-name>
4         <servlet-class>me.gacl.web.controller.VerifyServlet</servlet-class>
5     </servlet>
6     <servlet-mapping>
7         <servlet-name>VerifyServlet</servlet-name>
8         <url-pattern>/servlet/VerifyServlet</url-pattern>
9     </servlet-mapping>