2019独角兽企业重金招聘Python工程师标准>>> 
效果图
项目结构
index.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8" %>
randomcode
check.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
check
<%
// 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");
}
%>
<%
out.print(k + "---" + str);
%>
web.xml
Kaptcha
KaptchaServlet
图片边框，合法值：yes , no
kaptcha.border
yes
边框颜色，合法值： r,g,b (and optional alpha) 或者white,black,blue.
kaptcha.border.color
black
边框厚度，合法值：>0
kaptcha.border.thickness
1
图片宽 200
kaptcha.image.width
200
图片高 50
kaptcha.image.height
50
图片实现类
kaptcha.producer.impl
com.google.code.kaptcha.impl.DefaultKaptcha
文本实现类
kaptcha.textproducer.impl
com.google.code.kaptcha.text.impl.DefaultTextCreator
文本集合，验证码值从此集合中获取
kaptcha.textproducer.char.string
1234567890
验证码长度 5
kaptcha.textproducer.char.length
3
字体 Arial, Courier
kaptcha.textproducer.font.names
Arial, Courier
字体大小 40px.
kaptcha.textproducer.font.size
40
字体颜色，合法值： r,g,b 或者 white,black,blue.
kaptcha.textproducer.font.color
black
文字间隔 2
kaptcha.textproducer.char.space
2
干扰实现类
kaptcha.noise.impl
com.google.code.kaptcha.impl.DefaultNoise
干扰颜色，合法值： r,g,b 或者 white,black,blue.
kaptcha.noise.color
black
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
kaptcha.obscurificator.impl
com.google.code.kaptcha.impl.WaterRipple
背景实现类
kaptcha.background.impl
com.google.code.kaptcha.impl.DefaultBackground
背景颜色渐变，开始颜色
kaptcha.background.clear.from
green
背景颜色渐变，结束颜色
kaptcha.background.clear.to
white
文字渲染器
kaptcha.word.impl
com.google.code.kaptcha.text.impl.DefaultWordRenderer
session中存放验证码的key键
kaptcha.session.key
KAPTCHA_SESSION_KEY
生成日期kaptcha放入HttpSession。这是该项目的关键值会话。
kaptcha.session.date
KAPTCHA_SESSION_DATE
Kaptcha
/randomcode.jpg
index.jsp
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();
}
}
}