How to use open source tools to create web page verification codes-PHP Tutorial-php.cn

Development tools: eclipse, kaptcha-2.3.jar package.

1. Create a Web project;

2. Create a new Jsp page (the content includes a text box, an image container, and a submit button)

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

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3. Yes It can be seen that the source of the image verification code (src="randomcode.jpg") needs to be configured with the Web.xml file. (Leave it to the Servlet (the servlet is in kaptcha-2.3.jar) for processing)

<servlet>
<servlet-name>Kaptcha</servlet-name>
<servlet-class>com.google.code.kaptcha.servlet.KaptchaServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Kaptcha</servlet-name>
<url-pattern>/randomcode.jpg</url-pattern>
</servlet-mapping>

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4. Since the kaptcha-2.3.jar package is required, import the downloaded jar package into lib. (Just copy and paste)

Others:

1. Attributes of web page verification code

(1) Add border

<servlet>
<init-param>
<description>图片边框，合法值：yes , no</description>
<param-name>kaptcha.border</param-name>
<param-value>yes</param-value> <!-- yes 或者 no-->
</init-param>
</servlet>

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(2) Border Color

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

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(3) Border thickness

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

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(4) Image width

<init-param>
<description>图片宽 200</description>
<param-name>kaptcha.image.width</param-name>
<param-value>200</param-value>
</init-param>

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(5) Image height

<init-param>
<description>图片高 50</description>
<param-name>kaptcha.image.height</param-name>
<param-value>50</param-value>
</init-param>

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(6) Verification code collection

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

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(7) Verification code length

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

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(8) Font

<init-param>
<description>字体 Arial, Courier</description>
<param-name>kaptcha.textproducer.font.names</param-name>
<param-value>Arial, Courier</param-value>
</init-param>

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(9) Font size

<init-param>
<description>字体大小 40px.</description>
<param-name>kaptcha.textproducer.font.size</param-name>
<param-value>40</param-value>
</init-param>

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(10) Font color

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

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(11)The interval between each verification code

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

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(Twelve) Interference Realization

<init-param>
<description>干扰实现类</description>
<param-name>kaptcha.noise.impl</param-name>
<param-value>
<!-- com.google.code.kaptcha.impl.NoNoise -->
com.google.code.kaptcha.impl.DefaultNoise
</param-value>
</init-param>

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(Thirteen) Interference Color

<init-param>
<description>
干扰颜色，合法值： r,g,b 或者 white,black,blue.
</description>
<param-name>kaptcha.noise.color</param-name>
<param-value>black</param-value>
</init-param>

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(Fourteen) Background style

<init-param>
<description>
图片样式： 水纹com.google.code.kaptcha.impl.WaterRipple
鱼眼com.google.code.kaptcha.impl.FishEyeGimpy
阴影com.google.code.kaptcha.impl.ShadowGimpy
</description>
<param-name>kaptcha.obscurificator.impl</param-name>
<param-value>
com.google.code.kaptcha.impl.WaterRipple
</param-value>
</init-param>

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(Fifteen) Background implementation class

<init-param>
<description>背景实现类</description>
<param-name>kaptcha.background.impl</param-name>
<param-value>
com.google.code.kaptcha.impl.DefaultBackground
</param-value>
</init-param>

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(Sixteen) Background gradient color

<init-param>
<description>背景颜色渐变，开始颜色</description>
<param-name>kaptcha.background.clear.from</param-name>
<param-value>green</param-value>
</init-param>
<init-param>
<description>背景颜色渐变，结束颜色</description>
<param-name>kaptcha.background.clear.to</param-name>
<param-value>white</param-value>
</init-param>

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(17) Text renderer

<init-param>
<description> 文字渲染器 </description>
<param-name>kaptcha.word.impl</param-name>
<param-value>
com.google.code.kaptcha.text.impl.DefaultWordRenderer
</param-value>
</init-param>

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(18) The verification code of the image will be saved in the Session, and the value is

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

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(19) Image implementation category

<init-param>
<description>图片实现类</description>
<param-name>kaptcha.producer.impl</param-name>
<param-value>
com.google.code.kaptcha.impl.DefaultKaptcha
</param-value>
</init-param>

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(20) Text implementation class (you can rewrite this class to implement the verification code in Chinese)

<init-param>
<description>文本实现类</description>
<param-name>kaptcha.textproducer.impl</param-name>
<param-value>
com.google.code.kaptcha.text.impl.DefaultTextCreator
</param-value>
</init-param>

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Rewrite the text implementation class to implement the verification code in Chinese:

1. Create a category, inherit Configurable and implement TextProducer (in the jar package)

import com.google.code.kaptcha.text.TextProducer;
import com.google.code.kaptcha.util.Configurable;
import java.util.Random;
public class ChineseText extends Configurable implements TextProducer {
public String getText() {
int length = getConfig().getTextProducerCharLength();
String finalWord = "", firstWord = "";
int tempInt = 0;
String[] array = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9",
"a", "b", "c", "d", "e", "f" };
Random rand = new Random();
for (int i = 0; i < length; i++) {
switch (rand.nextInt(array.length)) {
case 1:
tempInt = rand.nextInt(26) + 65;
firstWord = String.valueOf((char) tempInt);
break;
case 2:
int r1,
r2,
r3,
r4;
String strH,
strL;// high&low
r1 = rand.nextInt(3) + 11; // 前闭后开[11,14)
if (r1 == 13) {
r2 = rand.nextInt(7);
} else {
r2 = rand.nextInt(16);
}
r3 = rand.nextInt(6) + 10;
if (r3 == 10) {
r4 = rand.nextInt(15) + 1;
} else if (r3 == 15) {
r4 = rand.nextInt(15);
} else {
r4 = rand.nextInt(16);
}
strH = array[r1] + array[r2];
strL = array[r3] + array[r4];
byte[] bytes = new byte[2];
bytes[0] = (byte) (Integer.parseInt(strH, 16));
bytes[1] = (byte) (Integer.parseInt(strL, 16));
firstWord = new String(bytes);
break;
default:
tempInt = rand.nextInt(10) + 48;
firstWord = String.valueOf((char) tempInt);
break;
}
finalWord += firstWord;
}
return finalWord;
}
}

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2. Modify the Web.xml configuration

<init-param>
<description>文本实现类</description>
<param-name>kaptcha.textproducer.impl</param-name>
<param-value>
ChineseText
</param-value>
</init-param>
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）
[html] view plain copy
<body>
<%
// 检查是否是正确的验证码
String k = (String) session.getAttribute(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);
String str = request.getParameter("r");
if (k.equals(str))
out.print("true");
out.print(k + "---" + str);
%>
</body>

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6. Extension (implementation of addition verification code)

1. Rewrite the KaptchaServlet class

import com.google.code.kaptcha.Producer;
import com.google.code.kaptcha.util.Config;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Properties;
import javax.imageio.ImageIO;
import javax.servlet.Servlet;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class KaptchaServlet extends HttpServlet implements Servlet {
private Properties props;
private Producer kaptchaProducer;
private String sessionKeyValue;
public KaptchaServlet() {
this.props = new Properties();
this.kaptchaProducer = null;
this.sessionKeyValue = null;
}
public void init(ServletConfig conf) throws ServletException {
super.init(conf);
ImageIO.setUseCache(false);
Enumeration initParams = conf.getInitParameterNames();
while (initParams.hasMoreElements()) {
String key = (String) initParams.nextElement();
String value = conf.getInitParameter(key);
this.props.put(key, value);
}
Config config = new Config(this.props);
this.kaptchaProducer = config.getProducerImpl();
this.sessionKeyValue = config.getSessionKey();
}
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
resp.setDateHeader("Expires", 0L);
resp.setHeader("Cache-Control", "no-store, no-cache, must-revalidate");
resp.addHeader("Cache-Control", "post-check=0, pre-check=0");
resp.setHeader("Pragma", "no-cache");
resp.setContentType("image/jpeg");
String capText = this.kaptchaProducer.createText();
String s1 = capText.substring(0, 1);
String s2 = capText.substring(1, 2);
int r = Integer.valueOf(s1).intValue() + Integer.valueOf(s2).intValue();
req.getSession().setAttribute(this.sessionKeyValue, String.valueOf(r));
BufferedImage bi = this.kaptchaProducer.createImage(s1+"+"+s2+"=?");
ServletOutputStream out = resp.getOutputStream();
ImageIO.write(bi, "jpg", out);
try {
out.flush();
} finally {
out.close();
}
}
}

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2. Modify the configuration file

<servlet>
<servlet-name>Kaptcha</servlet-name>
<servlet-class>KaptchaServlet</servlet-class>
</servlet>

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The above is the method introduced by the editor to use open source tools to create web page verification codes. , I hope it will be helpful to you. If you have any questions, please leave me a message and the editor will reply to you in time. I would also like to thank you all for your support of the PHP Chinese website!

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