使用JCaptcha生成验证码

使用JCaptcha工具包生成验证码

JCaptcha 官网地址 http://forge.octo.com/jcaptcha/confluence/display/general/Home

引入Lib包 （包括一些依赖包commons-collections等）

从Servlet看起

<!-- 验证码Servlet -->   <servlet>    <servlet-name>jcaptcha</servlet-name>    <servlet-class>com.ighost.cms.common.checkcode.ImageCaptchaServlet</servlet-class>   </servlet>   <servlet-mapping>    <servlet-name>jcaptcha</servlet-name>    <url-pattern>/CheckCode.svl</url-pattern>   </servlet-mapping>

package com.ighost.cms.common.checkcode; import java.awt.image.BufferedImage; import java.io.ByteArrayOutputStream; import java.io.IOException; import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.ServletOutputStream; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.springframework.web.context.WebApplicationContext; import org.springframework.web.context.support.WebApplicationContextUtils; import com.octo.captcha.service.CaptchaServiceException; import com.octo.captcha.service.image.ImageCaptchaService; import com.sun.image.codec.jpeg.JPEGCodec; import com.sun.image.codec.jpeg.JPEGImageEncoder; /**  * 验证码生成Servlet  * @author ghost  *  */ @SuppressWarnings("serial") public class ImageCaptchaServlet extends HttpServlet {  //验证码生成类  private ImageCaptchaService imageCaptchaService;  //Spring中的配置名称  private String beanName = "imageCaptchaService";    /**   * 初始化ImageCaptchaService 对象   */  @Override  public void init(ServletConfig config) throws ServletException {   System.out.println("servlet init is in");   super.init(config);   WebApplicationContext context = WebApplicationContextUtils            .getWebApplicationContext(config.getServletContext());   imageCaptchaService = (ImageCaptchaService)context.getBean(beanName,ImageCaptchaService.class);  }    @Override  protected void doGet(HttpServletRequest req, HttpServletResponse resp)    throws ServletException, IOException {   byte[] captchaChallengeAsJpeg = null;   // the output stream to render the captcha image as jpeg into   ByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream();   try {    // get the session id that will identify the generated captcha.    // the same id must be used to validate the response, the session id    // is a good candidate!    String captchaId = req.getSession().getId();    // call the ImageCaptchaService getChallenge method    BufferedImage challenge = imageCaptchaService      .getImageChallengeForID(captchaId, req.getLocale());    // a jpeg encoder    JPEGImageEncoder jpegEncoder = JPEGCodec      .createJPEGEncoder(jpegOutputStream);    jpegEncoder.encode(challenge);   } catch (IllegalArgumentException e) {    resp.sendError(HttpServletResponse.SC_NOT_FOUND);    return;   } catch (CaptchaServiceException e) {    resp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);    return;   }   captchaChallengeAsJpeg = jpegOutputStream.toByteArray();   // flush it in the response   resp.setHeader("Cache-Control", "no-store");   resp.setHeader("Pragma", "no-cache");   resp.setDateHeader("Expires", 0);   resp.setContentType("image/jpeg");   ServletOutputStream responseOutputStream = resp.getOutputStream();   responseOutputStream.write(captchaChallengeAsJpeg);   responseOutputStream.flush();   responseOutputStream.close();  } }

Servlet中需要的类在Bean中的配置

<!-- 验证码生成器 -->  <bean id="fastHashMapCaptchaStore" class="com.octo.captcha.service.captchastore.FastHashMapCaptchaStore"/>  <bean id="captchaEngineEx" class="com.ighost.cms.common.checkcode.CaptchaEngineEx"/>  <bean id="imageCaptchaService" class="com.ighost.cms.common.checkcode.CaptchaService">   <constructor-arg type="com.octo.captcha.service.captchastore.CaptchaStore" index="0">    <ref bean="fastHashMapCaptchaStore"/>   </constructor-arg>   <constructor-arg type="com.octo.captcha.engine.CaptchaEngine" index="1">    <ref bean="captchaEngineEx"/>   </constructor-arg>   <constructor-arg index="2">    <value>180</value>      </constructor-arg>   <constructor-arg index="3">    <value>100000</value>      </constructor-arg>   <constructor-arg index="4">    <value>75000</value>      </constructor-arg>   </bean>

具体完成生成的类

package com.ighost.cms.common.checkcode; import com.octo.captcha.engine.CaptchaEngine; import com.octo.captcha.service.captchastore.CaptchaStore; import com.octo.captcha.service.image.DefaultManageableImageCaptchaService; /*  * 自定义的验证码生成器  */ public class CaptchaService extends DefaultManageableImageCaptchaService {  public CaptchaService(){   super();  }    /**   * @param minSeconds   * @param maxStoreSize 最大缓存大小   * @param loadBefore   */  public CaptchaService(int minSeconds, int maxStoreSize, int loadBefore){   super(minSeconds, maxStoreSize, loadBefore);  }    public CaptchaService(CaptchaStore captchaStore, CaptchaEngine captchaEngine,        int minSeconds, int maxStroreSize, int loadBefore){   super(captchaStore, captchaEngine, minSeconds, maxStroreSize, loadBefore);  }    /**   * 重写验证方法   * 掩盖异常 当出现异常时判定为验证失败   */  @Override  public Boolean validateResponseForID(String ID, Object response) {   Boolean isHuman;      try{    isHuman = super.validateResponseForID(ID, response);   }   catch(Exception e){    isHuman = false;      }      return isHuman;  } }

package com.ighost.cms.common.checkcode; import java.awt.Color; import com.octo.captcha.component.image.backgroundgenerator.BackgroundGenerator; import com.octo.captcha.component.image.backgroundgenerator.GradientBackgroundGenerator; import com.octo.captcha.component.image.color.SingleColorGenerator; 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.BaffleTextDecorator; import com.octo.captcha.component.image.textpaster.textdecorator.TextDecorator; import com.octo.captcha.component.image.wordtoimage.ComposedWordToImage; import com.octo.captcha.component.image.wordtoimage.WordToImage; import com.octo.captcha.component.word.wordgenerator.RandomWordGenerator; import com.octo.captcha.component.word.wordgenerator.WordGenerator; import com.octo.captcha.engine.image.ListImageCaptchaEngine; import com.octo.captcha.image.gimpy.GimpyFactory; /**  * 自定义的验证码生成引擎  * @author ghost  *  */ public class CaptchaEngineEx extends ListImageCaptchaEngine {  /**   * 生成验证码的具体方法   */  @Override  protected void buildInitialFactories() {      //验证码的最小长度   Integer minAcceptedWordLength = new Integer(4);   //验证码的最大长度   Integer maxAcceptedWordLength = new Integer(5);      //验证码图片的高度宽度设定   Integer imageHeight = new Integer(40);   Integer imageWidth = new Integer(100);      //验证码中显示的字体大小   Integer minFontSize = new Integer(20);   Integer maxFontSize = new Integer(22);      //随机字符生成   //abcdefghijklmnopqrstuvwxyz   WordGenerator wordGenerator = new RandomWordGenerator("0123456789");      //背景颜色随机生成   BackgroundGenerator backgroundGenerator = new GradientBackgroundGenerator(     imageWidth, imageHeight, Color.white,Color.white);     //字体随机生成   FontGenerator fontGenerator = new RandomFontGenerator(minFontSize, maxFontSize);      //验证码的颜色   SingleColorGenerator singleColor = new SingleColorGenerator(Color.blue);      BaffleTextDecorator baffleTextDecorator = new BaffleTextDecorator(1, Color.white);   //可以创建多个   //LineTextDecorator lineTextDecorator = new LineTextDecorator(1, Color.blue);   //TextDecorator[] textDecorator = new TextDecorator[2];   //textDecorator[0] = lineTextDecorator;   TextDecorator[] textDecorator = new TextDecorator[1];   textDecorator[0] = baffleTextDecorator;      TextPaster textPaster = new DecoratedRandomTextPaster(     minAcceptedWordLength, maxAcceptedWordLength, singleColor,textDecorator);   //生成图片输出   WordToImage wordToImage = new ComposedWordToImage(     fontGenerator, backgroundGenerator, textPaster);      addFactory(new GimpyFactory(wordGenerator, wordToImage));   } }

最后在jsp页面中只需使用如下调用即可

<img id="checkcode" alt="看不清，点击换一张" src="../CheckCode.svl" border="1px" onclick="this.src='../CheckCode.svl?date=' + new Date().getTime()">