【java提高】---patchca生成验证码

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();  

            // 填充为灰色背景
            graphics.setColor(Color.GRAY);
            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();
    }
}  

本文是转载，同时自己亲自测试可行，上面的验证码截图就是实际效果   参考链接：http://blog.csdn.net/zhyh1986/article/details/7741244

同时需要patchca架包：http://download.csdn.net/download/caoniquanjiaariniday/7607495