Web验证码的实现方法(3)---开源组件Kaptcha

Kapatcha组件

Kaptcha组件实现更多功能的验证码功能,可以调整验证码的大小，图片背景，干扰线条颜色形状等，非常方便。有”加减法验证模式“和“中文模式”。

1，jsp部分

1.1--index.jsp

body>
<h1>Kapatcha验证码</h1>
<img alt="random" src="randomcode.jpg" onclick="changeR(this)" style="cursor: pointer;">
<form action="check.jsp">
<input type="text" name="r" value="">
<input type="submit" value="submit">
</form>
<br>
</body>

1.2--check.jsp

<%
String result = (String)request.getSession().getAttribute("KAPTCHA_SESSION_KEY");
String check = request.getParameter("r");
if(result.equals(check)){
out.println("验证码正确");
}else
out.println("验证码错误");
%>

2,--Servlet部分

2.1--加发求和验证码

这个也是要先导入jar包反正该项目的WEBROOT目录的lib包中
下载地址：目前未审核成功，日后加上，百度上也可以搜到，效果一样

package servlet;

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;//类似于map,有键值映射关系
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);

//设置用户缓存为false,用系统缓存防止图片过大导致内存溢出
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 {
//代理服务器端防止缓冲
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");
//设置内容格式为图片
resp.setContentType("image/jpeg");
//获得创建的两个随机数，并分离
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();
//计算结果存入Session的Attribute中
req.getSession().setAttribute(this.sessionKeyValue, String.valueOf(r));
//设置图片显示内容
BufferedImage bi = this.kaptchaProducer.createImage(s1+"+"+s2+"=?");
//获得response的输出流
ServletOutputStream out = resp.getOutputStream();
//绘制图片
ImageIO.write(bi, "jpg", out);
try {
out.flush();
} finally {
out.close();
}
}
}

2.2--中文验证码

package servlet;
import java.util.Random;

import com.google.code.kaptcha.text.TextProducer;
import com.google.code.kaptcha.util.Configurable;

public class ChineseText extends Configurable implements TextProducer {

//获得中文验证码文字
public String getText() {
int length = getConfig().getTextProducerCharLength();
//char[] charS = getConfig().getTextProducerCharString();

String[] s = new String[]{"慕","课","网","教","程","验","证","码","实","例"};

Random rand = new Random();
StringBuffer sb = new StringBuffer();
for(int i = 0; i < length; i++){
int ind = rand.nextInt(s.length);
sb.append(s[ind]);
}
return sb.toString();
}
/*获得数字英文大写字母验证码
*/
public String getText1() {
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)) {//16以内的随机数
case 1:
tempInt = rand.nextInt(26) + 65;//A~Z的ASCii码对应的数值
firstWord = String.valueOf((char) tempInt);//转化成字符型在转化成字符串型
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);//[0,7)
} else {
r2 = rand.nextInt(16);//[0,16)
}

r3 = rand.nextInt(6) + 10;//[10,16)
if (r3 == 10) {
r4 = rand.nextInt(15) + 1;
} else if (r3 == 15) {
r4 = rand.nextInt(15);
} else {
r4 = rand.nextInt(16);//[0,16)
}

strH = array[r1] + array[r2];
strL = array[r3] + array[r4];

byte[] bytes = new byte[2];
//16表示strH是十六进制，并返回十进制的数
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;//[48,58)对应ASCii码0~9
firstWord = String.valueOf((char) tempInt);
break;
}
finalWord += firstWord;
}
return finalWord;
}
}

3--web.xml部分

这个比较多，基本上能用到的功能都给出来了

<?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"> <welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<!-- 随机验证码的类路径  com.google.code.kaptcha.servlet.KaptchaServlet 当改为中文验证码时候要设置为此 -->
<servlet>
<servlet-name>Kaptcha</servlet-name>
<servlet-class>servlet.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>

<span style="white-space:pre">				</span><!-- 当为自定义中文验证码设置为servle.ChineseText -->

<span style="white-space:pre">				</span>servlet.ChineseText
<!--加减法时候设置为此 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>
<!--<param-value>abcde2345678gfynmnpwx</param-value>-->
<!--<param-value>慕课网教程验证码实例</param-value> -->
</init-param>
<init-param>
<description>验证码长度 5</description>
<param-name>kaptcha.textproducer.char.length</param-name>
<param-value>2</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.NoNoise -->
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>
The date the kaptcha is generated is put into the
HttpSession. This is the key value for that item in the
session.
</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>
</web-app>

总结：

kaptcha组件使用更加方便，自定义功能很多，这次实现了普通验证码功能和加法验证码功能，还可以设置自定义中文验证码，非常方便。