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使用开源工具制作网页验证码的方法

时间:2021-07-01 10:21:17 帮助过:12人阅读

开发工具:eclipse、kaptcha-2.3.jar包。

一、创建Web项目;

二、新建一个Jsp页面(内容有,一个文本框,一个图片容器,一个提交按钮)

  1. <body>
  2. <img alt="random" src="randomcode.jpg" onclick="changeR(this)" style="cursor: pointer;">
  3. <form action="check.jsp">
  4. <input type="text" name="r">
  5. <input type="submit" value="s">
  6. </form>
  7. </body>

三、可以看出图片验证码来源(src=“randomcode.jpg”)需配置Web.xml文件。(交给Servlet(该servlet在kaptcha-2.3.jar)处理)

  1. <servlet>
  2. <servlet-name>Kaptcha</servlet-name>
  3. <servlet-class>com.google.code.kaptcha.servlet.KaptchaServlet</servlet-class>
  4. </servlet>
  5. <servlet-mapping>
  6. <servlet-name>Kaptcha</servlet-name>
  7. <url-pattern>/randomcode.jpg</url-pattern>
  8. </servlet-mapping>

四、由于需要kaptcha-2.3.jar包,所以将下载好的jar包导入在lib中。(复制黏贴即可)

其他:

一、网页验证码的属性

(一)添加边框

  1. <servlet>
  2. <init-param>
  3. <description>图片边框,合法值:yes , no</description>
  4. <param-name>kaptcha.border</param-name>
  5. <param-value>yes</param-value> <!-- yes 或者 no-->
  6. </init-param>
  7. </servlet>

(二)边框颜色

  1. <init-param>
  2. <description>
  3. 边框颜色,合法值: r,g,b (and optional alpha) 或者white,black,blue.
  4. </description>
  5. <param-name>kaptcha.border.color</param-name>
  6. <param-value>black</param-value>
  7. </init-param>

(三)边框厚度

  1. <init-param>
  2. <description>边框厚度,合法值:>大于0 </description>
  3. <param-name>kaptcha.border.thickness</param-name>
  4. <param-value>1</param-value>
  5. </init-param>

(四)图片宽度

  1. <init-param>
  2. <description>图片宽 200</description>
  3. <param-name>kaptcha.image.width</param-name>
  4. <param-value>200</param-value>
  5. </init-param>

(五)图片高度

  1. <init-param>
  2. <description>图片高 50</description>
  3. <param-name>kaptcha.image.height</param-name>
  4. <param-value>50</param-value>
  5. </init-param>

(六)验证码集合

  1. <init-param>
  2. <description>文本集合,验证码值从此集合中获取</description>
  3. <param-name>kaptcha.textproducer.char.string</param-name>
  4. <param-value>1234567890</param-value> <!--纯数字 -->
  5. //<param-value>abcde2345678gfynmnpwx</param-value> <!-- 文字加英文-->
  6. </init-param>

(七)验证码长度

  1. <init-param>
  2. <description>验证码长度 默认是5 </description>
  3. <param-name>kaptcha.textproducer.char.length</param-name>
  4. <param-value>2</param-value>
  5. </init-param>

(八)字体

  1. <init-param>
  2. <description>字体 Arial, Courier</description>
  3. <param-name>kaptcha.textproducer.font.names</param-name>
  4. <param-value>Arial, Courier</param-value>
  5. </init-param>

(九)字体大小

  1. <init-param>
  2. <description>字体大小 40px.</description>
  3. <param-name>kaptcha.textproducer.font.size</param-name>
  4. <param-value>40</param-value>
  5. </init-param>

(十)字体颜色

  1. <init-param>
  2. <description>
  3. 字体颜色,合法值: r,g,b 或者 white,black,blue.
  4. </description>
  5. <param-name>kaptcha.textproducer.font.color</param-name>
  6. <param-value>black</param-value>
  7. </init-param>

(十一)每个验证码之间的间隔

  1. <init-param>
  2. <description>文字间隔 2</description>
  3. <param-name>kaptcha.textproducer.char.space</param-name>
  4. <param-value>2</param-value>
  5. </init-param>

(十二)干扰实现

  1. <init-param>
  2. <description>干扰实现类</description>
  3. <param-name>kaptcha.noise.impl</param-name>
  4. <param-value>
  5. <!-- com.google.code.kaptcha.impl.NoNoise -->
  6. com.google.code.kaptcha.impl.DefaultNoise
  7. </param-value>
  8. </init-param>

(十三)干扰颜色

  1. <init-param>
  2. <description>
  3. 干扰颜色,合法值: r,g,b 或者 white,black,blue.
  4. </description>
  5. <param-name>kaptcha.noise.color</param-name>
  6. <param-value>black</param-value>
  7. </init-param>

(十四)背景样式

  1. <init-param>
  2. <description>
  3. 图片样式: 水纹com.google.code.kaptcha.impl.WaterRipple
  4. 鱼眼com.google.code.kaptcha.impl.FishEyeGimpy
  5. 阴影com.google.code.kaptcha.impl.ShadowGimpy
  6. </description>
  7. <param-name>kaptcha.obscurificator.impl</param-name>
  8. <param-value>
  9. com.google.code.kaptcha.impl.WaterRipple
  10. </param-value>
  11. </init-param>

(十五)背景实现类

  1. <init-param>
  2. <description>背景实现类</description>
  3. <param-name>kaptcha.background.impl</param-name>
  4. <param-value>
  5. com.google.code.kaptcha.impl.DefaultBackground
  6. </param-value>
  7. </init-param>

(十六)背景渐变颜色

  1. <init-param>
  2. <description>背景颜色渐变,开始颜色</description>
  3. <param-name>kaptcha.background.clear.from</param-name>
  4. <param-value>green</param-value>
  5. </init-param>
  6. <init-param>
  7. <description>背景颜色渐变,结束颜色</description>
  8. <param-name>kaptcha.background.clear.to</param-name>
  9. <param-value>white</param-value>
  10. </init-param>

(十七)文字渲染器

  1. <init-param>
  2. <description> 文字渲染器 </description>
  3. <param-name>kaptcha.word.impl</param-name>
  4. <param-value>
  5. com.google.code.kaptcha.text.impl.DefaultWordRenderer
  6. </param-value>
  7. </init-param>

(十八)图片的验证码会保存在Session中,其中的值为

  1. <init-param>
  2. <description> session中存放验证码的key键 </description>
  3. <param-name>kaptcha.session.key</param-name>
  4. <param-value>KAPTCHA_SESSION_KEY</param-value>
  5. </init-param>

(十九)图片实现类别

  1. <init-param>
  2. <description>图片实现类</description>
  3. <param-name>kaptcha.producer.impl</param-name>
  4. <param-value>
  5. com.google.code.kaptcha.impl.DefaultKaptcha
  6. </param-value>
  7. </init-param>

(二十)文本实现类(可通过重写该类来实现验证码为中文)

  1. <init-param>
  2. <description>文本实现类</description>
  3. <param-name>kaptcha.textproducer.impl</param-name>
  4. <param-value>
  5. com.google.code.kaptcha.text.impl.DefaultTextCreator
  6. </param-value>
  7. </init-param>

重写文本实现类,实现验证码为中文:

1.创建一个类别,继承Configurable 实现TextProducer(在jar包中)

  1. import com.google.code.kaptcha.text.TextProducer;
  2. import com.google.code.kaptcha.util.Configurable;
  3. import java.util.Random;
  4. public class ChineseText extends Configurable implements TextProducer {
  5. public String getText() {
  6. int length = getConfig().getTextProducerCharLength();
  7. String finalWord = "", firstWord = "";
  8. int tempInt = 0;
  9. String[] array = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9",
  10. "a", "b", "c", "d", "e", "f" };
  11. Random rand = new Random();
  12. for (int i = 0; i < length; i++) {
  13. switch (rand.nextInt(array.length)) {
  14. case 1:
  15. tempInt = rand.nextInt(26) + 65;
  16. firstWord = String.valueOf((char) tempInt);
  17. break;
  18. case 2:
  19. int r1,
  20. r2,
  21. r3,
  22. r4;
  23. String strH,
  24. strL;// high&low
  25. r1 = rand.nextInt(3) + 11; // 前闭后开[11,14)
  26. if (r1 == 13) {
  27. r2 = rand.nextInt(7);
  28. } else {
  29. r2 = rand.nextInt(16);
  30. }
  31. r3 = rand.nextInt(6) + 10;
  32. if (r3 == 10) {
  33. r4 = rand.nextInt(15) + 1;
  34. } else if (r3 == 15) {
  35. r4 = rand.nextInt(15);
  36. } else {
  37. r4 = rand.nextInt(16);
  38. }
  39. strH = array[r1] + array[r2];
  40. strL = array[r3] + array[r4];
  41. byte[] bytes = new byte[2];
  42. bytes[0] = (byte) (Integer.parseInt(strH, 16));
  43. bytes[1] = (byte) (Integer.parseInt(strL, 16));
  44. firstWord = new String(bytes);
  45. break;
  46. default:
  47. tempInt = rand.nextInt(10) + 48;
  48. firstWord = String.valueOf((char) tempInt);
  49. break;
  50. }
  51. finalWord += firstWord;
  52. }
  53. return finalWord;
  54. }
  55. }

2.修改Web.xml配置

  1. <init-param>
  2. <description>文本实现类</description>
  3. <param-name>kaptcha.textproducer.impl</param-name>
  4. <param-value>
  5. ChineseText
  6. </param-value>
  7. </init-param>
  8. 五、验证码的校验(本文是利用check.jsp来校验的)保存在Session中,其中的键值为(第十八个属性)
  9. [html] view plain copy
  10. <body>
  11. <%
  12. // 检查是否是正确的验证码
  13. String k = (String) session.getAttribute(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);
  14. String str = request.getParameter("r");
  15. if (k.equals(str))
  16. out.print("true");
  17. out.print(k + "---" + str);
  18. %>
  19. </body>

六、扩展(加法验证码的实现)

1.重写KaptchaServlet类

  1. import com.google.code.kaptcha.Producer;
  2. import com.google.code.kaptcha.util.Config;
  3. import java.awt.image.BufferedImage;
  4. import java.io.IOException;
  5. import java.util.Enumeration;
  6. import java.util.Properties;
  7. import javax.imageio.ImageIO;
  8. import javax.servlet.Servlet;
  9. import javax.servlet.ServletConfig;
  10. import javax.servlet.ServletException;
  11. import javax.servlet.ServletOutputStream;
  12. import javax.servlet.http.HttpServlet;
  13. import javax.servlet.http.HttpServletRequest;
  14. import javax.servlet.http.HttpServletResponse;
  15. import javax.servlet.http.HttpSession;
  16. public class KaptchaServlet extends HttpServlet implements Servlet {
  17. private Properties props;
  18. private Producer kaptchaProducer;
  19. private String sessionKeyValue;
  20. public KaptchaServlet() {
  21. this.props = new Properties();
  22. this.kaptchaProducer = null;
  23. this.sessionKeyValue = null;
  24. }
  25. public void init(ServletConfig conf) throws ServletException {
  26. super.init(conf);
  27. ImageIO.setUseCache(false);
  28. Enumeration initParams = conf.getInitParameterNames();
  29. while (initParams.hasMoreElements()) {
  30. String key = (String) initParams.nextElement();
  31. String value = conf.getInitParameter(key);
  32. this.props.put(key, value);
  33. }
  34. Config config = new Config(this.props);
  35. this.kaptchaProducer = config.getProducerImpl();
  36. this.sessionKeyValue = config.getSessionKey();
  37. }
  38. public void doGet(HttpServletRequest req, HttpServletResponse resp)
  39. throws ServletException, IOException {
  40. resp.setDateHeader("Expires", 0L);
  41. resp.setHeader("Cache-Control", "no-store, no-cache, must-revalidate");
  42. resp.addHeader("Cache-Control", "post-check=0, pre-check=0");
  43. resp.setHeader("Pragma", "no-cache");
  44. resp.setContentType("image/jpeg");
  45. String capText = this.kaptchaProducer.createText();
  46. String s1 = capText.substring(0, 1);
  47. String s2 = capText.substring(1, 2);
  48. int r = Integer.valueOf(s1).intValue() + Integer.valueOf(s2).intValue();
  49. req.getSession().setAttribute(this.sessionKeyValue, String.valueOf(r));
  50. BufferedImage bi = this.kaptchaProducer.createImage(s1+"+"+s2+"=?");
  51. ServletOutputStream out = resp.getOutputStream();
  52. ImageIO.write(bi, "jpg", out);
  53. try {
  54. out.flush();
  55. } finally {
  56. out.close();
  57. }
  58. }
  59. }

2.修改配置文件

  1. <servlet>
  2. <servlet-name>Kaptcha</servlet-name>
  3. <servlet-class>KaptchaServlet</servlet-class>
  4. </servlet>

以上所述是小编给大家介绍的使用开源工具制作网页验证码的方法,希望对大家有所帮助,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对脚本之家网站的支持!

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