Java使用patchca生成验证码

原文地址：http://www.aiuxian.com/article/p-1599738.html
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：

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);                }            }        }    }}

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();    }}