cas添加驗證碼

cas添加驗證碼，折騰了很久，終於整理好了，很大部分都是借鑑http://binghejinjun.iteye.com/blog/1255293這個的。可是他的有一個很很差的地方就是不能提高驗證碼錯誤！

紅色字體的爲我添加的，能夠提示驗證碼錯誤！很簡單，感謝。原做者。謝謝。

 

1.   首先,我用的cas版本是3.4.6,驗證碼採用的是CAPTCHA,所需jar包能夠google搜索,部署好cas後.在web-info目錄下找到login-webflow.xml,打開,找到以下代碼: 

<view-state id="viewLoginForm" view="casLoginView" model="credentials"> 
        <var name="credentials" class="org.jasig.cas.authentication.principal.UsernamePasswordCredentials" /> 
        <binder> 
            <binding property="username" /> 
            <binding property="password" /> 
        </binder> 
        <on-entry> 
            <set name="viewScope.commandName" value="'credentials'" /> 
        </on-entry> 
<transition on="submit" bind="true" validate="true" to="realSubmit"> 
            <set name="flowScope.credentials" value="credentials" /> 
            <evaluate expression="authenticationViaFormAction.doBind(flowRequestContext, flowScope.credentials)" /> 
        </transition> 
</view-state> 

　　此段代碼的功能是綁定cas登陸過程當中的用戶名和密碼,再次咱們修改以下: 

<view-state id="viewLoginForm" view="casLoginView" model="credentials"> 
        <var name="credentials" class="org.jasig.cas.authentication.principal.UsernamePasswordCredentials" /> 
        <binder> 
            <binding property="username" /> 
            <binding property="password" /> 
        </binder> 
        <on-entry> 
            <set name="viewScope.commandName" value="'credentials'" /> 
        </on-entry> 
<transition on="submit" bind="true" validate="true" to="yzmSubmit"> 
            <set name="flowScope.credentials" value="credentials" /> 
            <evaluate expression="authenticationViaFormAction.doBind(flowRequestContext, flowScope.credentials)" /> 
        </transition> 
</view-state> 

　　也就是說,只須要修改realSubmit爲yzmSubmit便可.而後加入以下配置: 

  <!--fan add start--> 
<action-state id="yzmSubmit"> 
        <evaluate expression="yzmViaFormAction.submit(flowRequestContext，messageContext)" /> 
<transition on="success" to="realSubmit" /> 
<transition on="error" to="viewLoginForm" /> 
</action-state> 
<!--fan add end--> 

此段配置是自定義的驗證碼驗證器,用來驗證你提交的驗證碼的正確性. 
  2.在web-info下找到cas-servlet.xml,打開後,加入 

<!--fan add start--> 
<bean id="yzmViaFormAction" class="com.ivan.zhang.servlet.YzmAction" 
/> 

　　<!--fan add end-->此配置是註冊自定義的驗證碼 
  3.編寫以下類: 

package com.ivan.zhang.servlet; 

import com.ivan.zhang.CaptchaServiceSingleton; 
import com.octo.captcha.service.image.ImageCaptchaService; 
import java.io.PrintStream; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpSession; 
import org.jasig.cas.web.support.WebUtils; 
import org.springframework.webflow.core.collection.ParameterMap; 
import org.springframework.webflow.execution.RequestContext; 

public class YzmAction 
{ 
  public final String submit(RequestContext context) 
    throws Exception 
  { 
    Boolean flag = Boolean.valueOf(false); 
    System.out.println("YzmAction is submiting...................."); 
    String yzm = context.getRequestParameters().get("yzm"); 
    String captchaId = WebUtils.getHttpServletRequest(context).getSession().getId(); 
    flag = CaptchaServiceSingleton.getInstance().validateResponseForID(captchaId, 
      yzm); 
    if (flag.booleanValue()) { 
      return "success"; 
    } 
//我添加的改動。提示驗證碼錯誤

MessageBuilder msgBuilder = new MessageBuilder();
msgBuilder.defaultText("驗證碼錯誤！");
messageContext.addMessage(msgBuilder.error().build());

    return "error"; 
  } 
} 

　　其中,flag = CaptchaServiceSingleton.getInstance().validateResponseForID(captchaId, 
      yzm); 
此句話是爲了驗證提交的驗證碼和先前生成的驗證碼的正確性,以此做爲驗證結果跳轉的依據.CaptchaServiceSingleton此類是自定義類,稍後會附加完整的類供下載調試. 
4.打開web-info/view/jsp/default/ui/casLoginView.jsp,在密碼下面加入

<%--fan add start --%> 
<img alt="yzm" src="captcha.jpg"> 
<spring:message code="screen.welcome.label.yzm.accesskey" var="yzmAccessKey" /> 
<form:input cssClass="required" cssErrorClass="error" id="yzm" size="25" tabindex="1" accesskey="${yzmAccessKey}" path="yzm" autocomplete="false" htmlEscape="true" /> 
<%--fan add end --%> 

　　5. 最後一步則是註冊驗證碼生成器,打開web.xml文件,加入 

<servlet>  
        <servlet-name>jcaptcha</servlet-name>  
        <servlet-class>com.ivan.zhang.servlet.ImageCaptchaServlet</servlet-class>  
        <load-on-startup>0</load-on-startup>  
    </servlet> 
<servlet-mapping>  
        <servlet-name>jcaptcha</servlet-name>  
        <url-pattern>/captcha.jpg</url-pattern>  
    </servlet-mapping> 

　　ok,就這麼簡單.簡單解釋一下流程,web.xml中註冊的類是用來調用自定義的驗證碼生成器,以便在顯示登錄界面的時候繪製驗證碼圖片,並在session中生成標誌位並記錄,當用戶提交驗證碼和用戶名密碼時,會先走自定義的驗證碼驗證器(此時會先驗證驗證碼的正確性),若是正確,再走用戶名和密碼的驗證,若是不正確,則直接跳轉回登錄頁面.yzm.jar是自定義的驗證碼生成器和驗證類,直接打包好後放到web-info/lib下.