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算式验证码实现

2016-07-26 00:00 197 查看
摘要: 算式验证码实现

效果图



项目结构



index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>randomcode</title>
<script type="text/javascript">
function changeR(node) {
// 用于点击时产生不同的验证码
node.src = "randomcode.jpg?time=" + new Date().getTime();
}
</script>
</head>
<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="提交">
</form>
</body>
</html>

check.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>check</title>
</head>
<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("验证码输入正确");
} else {
out.print("验证码输入错误");
}
%>
<br/>
<%
out.print(k + "---" + str);
%>
</body>
</html>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> 
<!-- 登陆验证码Kaptcha 2-->
<servlet>
<servlet-name>Kaptcha</servlet-name>
<servlet-class>KaptchaServlet</servlet-class>
<init-param>
<description>图片边框，合法值：yes , no</description>
<param-name>kaptcha.border</param-name>
<param-value>yes</param-value>
</init-param>
<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>
<init-param>
<description>边框厚度，合法值：>0</description>
<param-name>kaptcha.border.thickness</param-name>
<param-value>1</param-value>
</init-param>
<init-param>
<description>图片宽 200</description>
<param-name>kaptcha.image.width</param-name>
<param-value>200</param-value>
</init-param>
<init-param>
<description>图片高 50</description>
<param-name>kaptcha.image.height</param-name>
<param-value>50</param-value>
</init-param>
<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>
<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>
<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>
</init-param>
<init-param>
<description>验证码长度 5</description>
<param-name>kaptcha.textproducer.char.length</param-name>
<param-value>3</param-value>
</init-param>
<init-param>
<description>字体 Arial, Courier</description>
<param-name>kaptcha.textproducer.font.names</param-name>
<param-value>Arial, Courier</param-value>
</init-param>
<init-param>
<description>字体大小 40px.</description>
<param-name>kaptcha.textproducer.font.size</param-name>
<param-value>40</param-value>
</init-param>
<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>
<init-param>
<description>文字间隔 2</description>
<param-name>kaptcha.textproducer.char.space</param-name>
<param-value>2</param-value>
</init-param>
<init-param>
<description>干扰实现类</description>
<param-name>kaptcha.noise.impl</param-name>
<param-value>com.google.code.kaptcha.impl.DefaultNoise</param-value>
</init-param>
<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>
<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>
<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>
<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>
<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>
<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>
<init-param>
<description>生成日期kaptcha放入HttpSession。这是该项目的关键值会话。</description>
<param-name>kaptcha.session.date</param-name>
<param-value>KAPTCHA_SESSION_DATE</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>Kaptcha</servlet-name>
<url-pattern>/randomcode.jpg</url-pattern>
</servlet-mapping>

<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>

KaptchaServlet

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 java.util.Random;
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;

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, (new Random().nextInt(3) + 1));
String s2 = capText.substring((new Random().nextInt(2) + 1), 3);
int r = Integer.valueOf(s1) + Integer.valueOf(s2);

req.getSession().setAttribute(this.sessionKeyValue, String.valueOf(r));
BufferedImage bi = this.kaptchaProducer.createImage(Integer.valueOf(s1) + "+" + Integer.valueOf(s2) + "=?");
ServletOutputStream out = resp.getOutputStream();
ImageIO.write(bi, "jpg", out);
try {
out.flush();
} finally {
out.close();
}
}
}
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