Java使用patchca生成验证码

package com.ninemax.cul.servlet;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.awt.image.BufferedImageOp;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.patchca.background.BackgroundFactory;
import org.patchca.color.ColorFactory;
import org.patchca.color.RandomColorFactory;
import org.patchca.filter.ConfigurableFilterFactory;
import org.patchca.filter.library.AbstractImageOp;
import org.patchca.filter.library.WobbleImageOp;
import org.patchca.font.RandomFontFactory;
import org.patchca.service.Captcha;
import org.patchca.service.ConfigurableCaptchaService;
import org.patchca.text.renderer.BestFitTextRenderer;
import org.patchca.text.renderer.TextRenderer;
import org.patchca.word.RandomWordFactory;

/**
* 验证码生成类
*
* 使用开源验证码项目patchca生成
* 依赖jar包：patchca-0.5.0.jar
* 项目网址：https://code.google.com/p/patchca/
*
* @author zyh
* @version 1.00  2012-7-12 New
*/
public class ValidationCodeServlet extends HttpServlet {
private static final long serialVersionUID = 5126616339795936447L;

private ConfigurableCaptchaService configurableCaptchaService = null;
private ColorFactory colorFactory = null;
private RandomFontFactory fontFactory = null;
private RandomWordFactory wordFactory = null;
private TextRenderer textRenderer = null;

public ValidationCodeServlet() {
super();
}

/**
* Servlet销毁方法,负责销毁所使用资源. <br>
*/
public void destroy() {
wordFactory = null;
colorFactory = null;
fontFactory = null;
textRenderer = null;
configurableCaptchaService = null;
super.destroy(); // Just puts "destroy" string in log
}

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}

public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("image/png");
response.setHeader("cache", "no-cache");

HttpSession session = request.getSession(true);
OutputStream outputStream = response.getOutputStream();

// 得到验证码对象,有验证码图片和验证码字符串
Captcha captcha = configurableCaptchaService.getCaptcha();
// 取得验证码字符串放入Session
String validationCode = captcha.getChallenge();
session.setAttribute("validationCode", validationCode);
// 取得验证码图片并输出
BufferedImage bufferedImage = captcha.getImage();
ImageIO.write(bufferedImage, "png", outputStream);

outputStream.flush();
outputStream.close();
}

/**
* Servlet初始化方法
*/
public void init() throws ServletException {
configurableCaptchaService = new ConfigurableCaptchaService();

// 颜色创建工厂,使用一定范围内的随机色
colorFactory = new RandomColorFactory();
configurableCaptchaService.setColorFactory(colorFactory);

// 随机字体生成器
fontFactory = new RandomFontFactory();
fontFactory.setMaxSize(32);
fontFactory.setMinSize(28);
configurableCaptchaService.setFontFactory(fontFactory);

// 随机字符生成器,去除掉容易混淆的字母和数字,如o和0等
wordFactory = new RandomWordFactory();
wordFactory.setCharacters("abcdefghkmnpqstwxyz23456789");
wordFactory.setMaxLength(5);
wordFactory.setMinLength(4);
configurableCaptchaService.setWordFactory(wordFactory);

// 自定义验证码图片背景
MyCustomBackgroundFactory backgroundFactory = new MyCustomBackgroundFactory();
configurableCaptchaService.setBackgroundFactory(backgroundFactory);

// 图片滤镜设置
ConfigurableFilterFactory filterFactory = new ConfigurableFilterFactory();

List<BufferedImageOp> filters = new ArrayList<BufferedImageOp>();
WobbleImageOp wobbleImageOp = new WobbleImageOp();
wobbleImageOp.setEdgeMode(AbstractImageOp.EDGE_MIRROR);
wobbleImageOp.setxAmplitude(2.0);
wobbleImageOp.setyAmplitude(1.0);
filters.add(wobbleImageOp);
filterFactory.setFilters(filters);

configurableCaptchaService.setFilterFactory(filterFactory);

// 文字渲染器设置
textRenderer = new BestFitTextRenderer();
textRenderer.setBottomMargin(3);
textRenderer.setTopMargin(3);
configurableCaptchaService.setTextRenderer(textRenderer);

// 验证码图片的大小
configurableCaptchaService.setWidth(82);
configurableCaptchaService.setHeight(32);
}

/**
* 自定义验证码图片背景,主要画一些噪点和干扰线
*/
private class MyCustomBackgroundFactory implements BackgroundFactory {
private Random random = new Random();

public void fillBackground(BufferedImage image) {
Graphics graphics = image.getGraphics();

// 验证码图片的宽高
int imgWidth = image.getWidth();
int imgHeight = image.getHeight();

// 填充为白色背景
graphics.setColor(Color.WHITE);
graphics.fillRect(0, 0, imgWidth, imgHeight);

// 画100个噪点(颜色及位置随机)
for(int i = 0; i < 100; i++) {
// 随机颜色
int rInt = random.nextInt(255);
int gInt = random.nextInt(255);
int bInt = random.nextInt(255);

graphics.setColor(new Color(rInt, gInt, bInt));

// 随机位置
int xInt = random.nextInt(imgWidth - 3);
int yInt = random.nextInt(imgHeight - 2);

// 随机旋转角度
int sAngleInt = random.nextInt(360);
int eAngleInt = random.nextInt(360);

// 随机大小
int wInt = random.nextInt(6);
int hInt = random.nextInt(6);

graphics.fillArc(xInt, yInt, wInt, hInt, sAngleInt, eAngleInt);

// 画5条干扰线
if (i % 20 == 0) {
int xInt2 = random.nextInt(imgWidth);
int yInt2 = random.nextInt(imgHeight);
graphics.drawLine(xInt, yInt, xInt2, yInt2);
}
}
}
}
}

<servlet>
<servlet-name>validationCode</servlet-name>
<servlet-class>com.ninemax.cul.servlet.ValidationCodeServlet</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>validationCode</servlet-name>
<url-pattern>/validationCodeServlet.png</url-pattern>
</servlet-mapping>

<img id="validationCode" alt="验证码图片" title="验证码图片" src="<%=path %>/validationCodeServlet.png" onclick="refreshCode(this)" />
<a id="aRecode" href="javascript:void(0);" onclick="refreshCode()">换一张</a>

/**
* 刷新验证码
* @param imgObj 验证码Img元素
*/
function refreshCode(imgObj) {
if (!imgObj) {
imgObj = document.getElementById("validationCode");
}
var index = imgObj.src.indexOf("?");
if(index != -1) {
var url = imgObj.src.substring(0,index + 1);
imgObj.src = url + Math.random();
} else {
imgObj.src = imgObj.src + "?" + Math.random();
}
}