stucts 里面用 jcaptcha 做登录验证码
jcaptcha是专业的解决方案，做到了极致，没必要自己去写了
下载之：http://sourceforge.net/projects/jcaptcha/files/
根据他官方的例子，在struts中集成方法如下
环境：struts 1.3.x? jcaptcha 1.0
1. 加载lib
把jcaptcha-1.0-all.jar 和 jcaptcha-integration-struts-1.0.jar 放到工程的lib里面，并设置包含之
2. 配置struts-config.xml
加plug-in描述
<!-- WizRtf2Html Charset=0 --><plug-in className=“com.octo.captcha.module.struts.CaptchaServicePlugin”/>加引用的 action
<!-- WizRtf2Html Charset=0 --><action-mappings>这个里面加以下代码<!– add the render action–><actionpath=“/jcaptcha”type=“com.octo.captcha.module.struts.image.RenderImageCaptchaAction”></action>即：可用 http://server/proj/jcaptcha.do 调用(如果你设置的是 *.do)?? http://server/proj/do/jcapcha(如果你设置的是 /do/*的话) 显示生成的图片
运行起来后，在浏览器中应该可以看到图片了
3. jsp中集成
如 login.jsp中
最前面加入taglib定义
<%– Add the jcaptcha taglib–%>
<%@ taglib uri=“http://jcaptcha.sourceforge.net” prefix=“jcaptcha”%>
增加显示和校验代码
<%– Add the jcaptcha form part–%>
<input type=“text” name=“jcaptcha_response” />
<!– 加入错误提示，改成用errors了–>
<font class=“required_error_font”>?<html:errors property=“jcaptcha_error_msg” /></font><br/>
<font size=“-1″ color=“#6f6f6f”><jcaptcha:question/></font><br/>
<%– Add the image–%>
<img name=“jcaptcha” id=“jcaptcha” onclick=“refresh_jcaptcha(this)” src=“<%=request.getContextPath()%>/do/jcaptcha” alt=“click to refresh” style=“cursor:pointer;”/>
增加了个点击刷新的功能，脚本如下
<!-- WizRtf2Html Charset=0 --><script language=“Javascript”>function refresh_jcaptcha(obj){//alert(obj);obj.src=”<%=request.getContextPath()%>/do/jcaptcha?” + Math.random();</script>
?
4. 在提交页面对应的Action.excute()中增加校验代码处理 request
我把他封装成了函数
<!-- WizRtf2Html Charset=0 -->public boolean isJcaptchaOK(HttpServletRequest request){log.debug(“enter captcha challenge verification”);CaptchaService service = CaptchaServicePlugin.getInstance().getService();String responseKey = CaptchaServicePlugin.getInstance().getResponseKey();String captchaID = CaptchaModuleConfigHelper.getId(request);String challengeResponse = request.getParameter(responseKey);if (log.isDebugEnabled())log.debug(“response for id “ + captchaID + ” : “ + challengeResponse);request.removeAttribute(responseKey);boolean isResponseCorrect = false;if (challengeResponse != null)try {isResponseCorrect = service.validateResponseForID(captchaID,challengeResponse).booleanValue();} catch (CaptchaServiceException e) {log.debug(“Error during challenge verification”, e);request.setAttribute(CaptchaServicePlugin.getInstance().getMessageKey(),CaptchaModuleConfigHelper.getMessage(request));log.debug(“forward to error with message : “ + CaptchaModuleConfigHelper.getMessage(request));throw(e);//抛出程序应用异常}if (isResponseCorrect) {log.debug(“correct : forward to success”);return true;//正确}if (log.isDebugEnabled()) {log.debug(“false : forward to failure with message : “+ CaptchaModuleConfigHelper.getMessage(request));log.debug(“in request attribute key : “+ CaptchaServicePlugin.getInstance().getMessageKey());}ActionErrors errors = new ActionErrors();//用ActionError替换了他自己的Messageerrors.add(“jcaptcha_error_msg”, new ActionMessage(“error.jcaptcha.error.inputInvalid”));this.addErrors(request, errors);return false;}—–
excute(…)中：
<!-- WizRtf2Html Charset=0 -->if(!isJcaptchaOK(request))????return mapping.findForward(“return_form”); //返回页面