Java使用patchca生成验证码

Patchca是Piotr Piastucki写的一个java验证码开源库，打包成jar文件发布，patchca使用简单但功能强大。

本例实现了自定义背景，由于生成图片较小，波动太大时会导致部分文字显示不全，所以更改了滤镜属性。

效果图：

代码如下：

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SessionString 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);}}}}}

由于是个Servlet所以web.xml配置如下：

<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>

JSP引用(部分)：

<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>

JS重新载入图片方法(参考)：

/** * 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();}}