captcha

代码摘录自网络，可参考

import com.octo.captcha.service.captchastore.FastHashMapCaptchaStore;
import com.octo.captcha.service.image.DefaultManageableImageCaptchaService;
import com.octo.captcha.service.image.ImageCaptchaService;

public class CaptchaServiceSingleton {

    private static ImageCaptchaService instance = new DefaultManageableImageCaptchaService(
            new FastHashMapCaptchaStore(), new GMailEngine(), 180, 100000, 75000);

    public static ImageCaptchaService getInstance() {
        return instance;
    }

}

import java.awt.Color;
import java.awt.Font;
import java.awt.image.ImageFilter;
import com.octo.captcha.component.image.backgroundgenerator.BackgroundGenerator;
import com.octo.captcha.component.image.backgroundgenerator.UniColorBackgroundGenerator;
import com.octo.captcha.component.image.color.RandomListColorGenerator;
import com.octo.captcha.component.image.deformation.ImageDeformation;
import com.octo.captcha.component.image.deformation.ImageDeformationByFilters;
import com.octo.captcha.component.image.fontgenerator.FontGenerator;
import com.octo.captcha.component.image.fontgenerator.RandomFontGenerator;
import com.octo.captcha.component.image.textpaster.DecoratedRandomTextPaster;
import com.octo.captcha.component.image.textpaster.TextPaster;
import com.octo.captcha.component.image.textpaster.textdecorator.TextDecorator;
import com.octo.captcha.component.image.wordtoimage.DeformedComposedWordToImage;
import com.octo.captcha.component.image.wordtoimage.WordToImage;
import com.octo.captcha.component.word.FileDictionary;
import com.octo.captcha.component.word.wordgenerator.ComposeDictionaryWordGenerator;
import com.octo.captcha.component.word.wordgenerator.WordGenerator;
import com.octo.captcha.engine.image.ListImageCaptchaEngine;
import com.octo.captcha.image.gimpy.GimpyFactory;

/**
 * 仿照JCaptcha2.0编写GMail验证码样式的图片引擎.
 * 
 * @author Administrator
 */
public class GMailEngine extends ListImageCaptchaEngine {
    @Override
    protected void buildInitialFactories() {

        int minWordLength = 4;
        int maxWordLength = 5;
        int fontSize = 24;
        int imageWidth = 100;
        int imageHeight = 40;

        // word generator
        WordGenerator dictionnaryWords = new ComposeDictionaryWordGenerator(new FileDictionary("toddlist"));

        // word2image components
        TextPaster randomPaster = new DecoratedRandomTextPaster(minWordLength, maxWordLength,
                new RandomListColorGenerator(
                        new Color[] { new Color(23, 170, 27), new Color(220, 34, 11), new Color(23, 67, 172) }),
                new TextDecorator[] {});

        BackgroundGenerator background = new UniColorBackgroundGenerator(imageWidth, imageHeight, Color.white);
        FontGenerator font = new RandomFontGenerator(fontSize, fontSize,
                new Font[] { new Font("nyala", Font.BOLD, fontSize), new Font("Bell MT", Font.PLAIN, fontSize),
                        new Font("Credit valley", Font.BOLD, fontSize) });
        ImageDeformation postDef = new ImageDeformationByFilters(new ImageFilter[] {});
        ImageDeformation backDef = new ImageDeformationByFilters(new ImageFilter[] {});
        ImageDeformation textDef = new ImageDeformationByFilters(new ImageFilter[] {});
        WordToImage word2image = new DeformedComposedWordToImage(font, background, randomPaster, backDef, textDef,
                postDef);
        addFactory(new GimpyFactory(dictionnaryWords, word2image));
    }
}

 此处使用spring-mvc

    @RequestMapping("/obtainCaptchaImage")
    public void obtainCaptchaImage(HttpServletRequest request, HttpServletResponse response, HttpSession session, Model model) throws IOException {

        byte[] captchaChallengeAsJpeg = null;
        ByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream();

        String captchaId = request.getSession().getId();
        BufferedImage challenge = new BufferedImage(68, 22, BufferedImage.TYPE_INT_RGB);
        
        challenge = CaptchaServiceSingleton.getInstance().getImageChallengeForID(captchaId,request.getLocale());

        ImageIO.write(challenge, "jpg", jpegOutputStream);
        captchaChallengeAsJpeg = jpegOutputStream.toByteArray();
        response.setHeader("Cache-Control", "no-store");
        response.setHeader("Pragma", "no-cache");
        response.setDateHeader("Expires", 0);
        response.setContentType("image/jpeg");
        ServletOutputStream responseOutputStream = response.getOutputStream();
        responseOutputStream.write(captchaChallengeAsJpeg);
        responseOutputStream.flush();
        responseOutputStream.close();

    }

<tr>
                        <td><span>验证码</span></td>
                        <td><input type="text" id="j_captcha_response" name="j_captcha_response"/><img src="" th:src="@{/obtainCaptchaImage}" /></td>
                    </tr>

        HttpServletRequest httpRequest = (HttpServletRequest)request;
        
        Boolean isResponseCorrect = Boolean.FALSE;
        
        String captchaId = httpRequest.getSession().getId();
        String responsestr = request.getParameter("j_captcha_response");
         
        log.debug("captchaId={}", captchaId);
        log.debug("responsestr={}", responsestr);
         
        isResponseCorrect = CaptchaServiceSingleton.getInstance().validateResponseForID(captchaId, responsestr);