CAS添加验证码功能

1.  cas.war 下面的web-inf/web.xml  lib添加  kaptcha.jar

　　kaptcha.jar通过maven获取

 <dependency>
    <groupId>com.github.axet</groupId>
    <artifactId>kaptcha</artifactId>
    <version>0.0.9</version>
 </dependency>

这个maven 包含两个 jar 另一个是filters-2.0.235.jar

2. cas.war 下面的web-inf/web.xml添加验证码映射

<servlet>
        <servlet-name>Kaptcha</servlet-name>
        <servlet-class>com.google.code.kaptcha.servlet.KaptchaServlet</servlet-class>
        <init-param>
            <param-name>kaptcha.border</param-name>
            <param-value>no</param-value>
        </init-param>
        <init-param>
            <param-name>kaptcha.textproducer.char.space</param-name>
            <param-value>5</param-value>
        </init-param>
        <init-param>
            <param-name>kaptcha.textproducer.char.length</param-name>
            <param-value>5</param-value>
        </init-param>
    </servlet>  

    <servlet-mapping>
        <servlet-name>Kaptcha</servlet-name>
        <url-pattern>/captcha.jpg</url-pattern>
</servlet-mapping>  

3. cas中 UsernamePasswordCredentials 类增加验证码属性 authcode

/** The authcode. */
   @NotNull
   @Size(min=1, message = "required.authcode")
   private String authcode;  

public String getAuthcode() {
    return authcode;
}  

public void setAuthcode(String authcode) {
    this.authcode = authcode;
}  

/**
    * @return Returns the password.
    */
   public final String getPassword() {
       return this.password;
   }  

并且重写equals和hashCode方法

@Override
   public boolean equals(final Object o) {
       if (this == o) return true;
       if (o == null || getClass() != o.getClass()) return false;  

       UsernamePasswordCredentials that = (UsernamePasswordCredentials) o;  

       if (password != null ? !password.equals(that.password) : that.password != null) return false;
       if (username != null ? !username.equals(that.username) : that.username != null) return false;
       if (authcode != null ? !authcode.equals(that.authcode) : that.authcode != null) return false;
       return true;
   }  

   @Override
   public int hashCode() {
       int result = username != null ? username.hashCode() : 0;
       result = 31 * result + (password != null ? password.hashCode() : 0);
       result = 31 * result + (authcode != null ? authcode.hashCode() : 0);
       return result;
   }  

4. AuthenticationViaFormAction 类增加验证方法

public final String validatorCode(final RequestContext context,  final Credentials credentials, final MessageContext messageContext) throws Exception {
        final HttpServletRequest request = WebUtils.getHttpServletRequest(context);
        HttpSession session = request.getSession();
        String authcode = (String)session.getAttribute(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);
        session.removeAttribute(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);  

        UsernamePasswordCredentials upc = (UsernamePasswordCredentials)credentials;
        String submitAuthcode =upc.getAuthcode();
        if(!StringUtils.hasText(submitAuthcode) || !StringUtils.hasText(authcode)){
            populateErrorsInstance(new NullAuthcodeAuthenticationException(),messageContext);
            return "error";
        }
        if(submitAuthcode.equals(authcode)){
            return "success";
        }
        populateErrorsInstance(new BadAuthcodeAuthenticationException(),messageContext);
        return "error";
    }  

NullAuthcodeAuthenticationException 、BadAuthcodeAuthenticationException为定义的异常类，取得异常编码

/*
 * Licensed to Jasig under one or more contributor license
 * agreements. See the NOTICE file distributed with this work
 * for additional information regarding copyright ownership.
 * Jasig licenses this file to you under the Apache License,
 * Version 2.0 (the "License"); you may not use this file
 * except in compliance with the License.  You may obtain a
 * copy of the License at the following location:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.jasig.cas.authentication.handler;  

import org.jasig.cas.ticket.TicketException;  

/**
 * The exception to throw when we know the authcode is null
 *
 * @author Scott Battaglia
 * @version $Revision$ $Date$
 * @since 3.0
 */
public class NullAuthcodeAuthenticationException extends TicketException {  

    /** Serializable ID for unique id. */
    private static final long serialVersionUID = 5501212207531289993L;  

    /** Code description. */
    public static final String CODE = "required.authcode";  

    /**
     * Constructs a TicketCreationException with the default exception code.
     */
    public NullAuthcodeAuthenticationException() {
        super(CODE);
    }  

    /**
     * Constructs a TicketCreationException with the default exception code and
     * the original exception that was thrown.
     *
     * @param throwable the chained exception
     */
    public NullAuthcodeAuthenticationException(final Throwable throwable) {
        super(CODE, throwable);
    }}  

/*
 * Licensed to Jasig under one or more contributor license
 * agreements. See the NOTICE file distributed with this work
 * for additional information regarding copyright ownership.
 * Jasig licenses this file to you under the Apache License,
 * Version 2.0 (the "License"); you may not use this file
 * except in compliance with the License.  You may obtain a
 * copy of the License at the following location:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.jasig.cas.authentication.handler;  

import org.jasig.cas.ticket.TicketException;  

/**
 * The exception to throw when we know the authcoe is not correct
 *
 * @author Scott Battaglia
 * @version $Revision$ $Date$
 * @since 3.0
 */
public class BadAuthcodeAuthenticationException extends TicketException {  

    /** Serializable ID for unique id. */
    private static final long serialVersionUID = 5501212207531289993L;  

    /** Code description. */
    public static final String CODE = "error.authentication.authcode.bad";  

    /**
     * Constructs a TicketCreationException with the default exception code.
     */
    public BadAuthcodeAuthenticationException() {
        super(CODE);
    }  

    /**
     * Constructs a TicketCreationException with the default exception code and
     * the original exception that was thrown.
     *
     * @param throwable the chained exception
     */
    public BadAuthcodeAuthenticationException(final Throwable throwable) {
        super(CODE, throwable);
    }}  

5. login_webflow.xml 修改登录验证流程

<view-state id="viewLoginForm" view="casLoginView" model="credentials">
        <binder>
            <binding property="username" />
            <binding property="password" />
            <binding property="authcode" />
        </binder>
        <on-entry>
            <set name="viewScope.commandName" value="'credentials'" />
        </on-entry>
        <transition on="submit" bind="true" validate="true" to="authcodeValidate">
            <evaluate expression="authenticationViaFormAction.doBind(flowRequestContext, flowScope.credentials)" />
        </transition>
    </view-state>  

    <action-state id="authcodeValidate">
        <evaluate expression="authenticationViaFormAction.validatorCode(flowRequestContext, flowScope.credentials, messageContext)" />
        <transition on="error" to="generateLoginTicket" />
        <transition on="success" to="realSubmit" />
    </action-state> 

6. 增加国际化显示信息

在messages_zh_CN.properties文件中添加，其他国家语言类似添加

screen.welcome.label.authcode=\u9A8C\u8BC1\u7801:
screen.welcome.label.authcode.accesskey=a
required.authcode=\u5FC5\u987B\u5F55\u5165\u9A8C\u8BC1\u7801\u3002
error.authentication.authcode.bad=\u9A8C\u8BC1\u7801\u8F93\u5165\u6709\u8BEF\u3002  

7. 登录页面casLoginView.jsp添加验证码输入框

<div class="row fl-controls-left">
                      <label for="authcode"><spring:message code="screen.welcome.label.authcode" /></label>
                      <spring:message code="screen.welcome.label.authcode.accesskey" var="authcodeAccessKey" />
                        <table>
                        <tr>
                                <td>
                        <form:input cssClass="required" cssErrorClass="error" id="authcode" size="10" tabindex="2" path="authcode"  accesskey="${authcodeAccessKey}" htmlEscape="true" autocomplete="off" />
                        </td>
                                <td align="left" valign="bottom" style="vertical-align: bottom;">
                          <img alt="<spring:message code="required.authcode" />" onclick="this.src='captcha.jpg?'+Math.random()" width="93" height="30" src="captcha.jpg">
                    </td>
                        </tr>
                        </table>
                    </div>
                    <div class="row check">
                        <input id="warn" name="warn" value="true" tabindex="3" accesskey="<spring:message code="screen.welcome.label.warn.accesskey" />" type="checkbox" />
                        <label for="warn"><spring:message code="screen.welcome.label.warn" /></label>
                    </div> 

以上操作有些要修改源码，所以还是要把源码下载下来部署到Eclipse上修改比较方便，修改后编译成class文件放入到cas web里面