单点登录CAS服务端登录页添加验证码

啰嗦一句：这年头验证码一般用来防止帐号被暴力破解，若系统走专线（也就是说放在内网），那完全没必要搞验证码

1、由于CAS使用了SpringWebFlow，所以我们想在登录页表单中增加属性就直接找 /WEB-INF/login-webflow.xml

2、在第84行 <view-state id="viewLoginForm"> 中找到表单的两个属性，我们加一个

同样该标签中会发现model=”credential”配置，所以我们就在该文件找credential对应的实体类配置

发现是在第27行设置的，其值为org.jasig.cas.authentication.UsernamePasswordCredential

这是一个用来接收前台表单参数的JavaBean，我们这里要在表单上加一个参数captcha，所以继承它就行了

3、创建com.jadyer.sso.model.UsernamePasswordCaptchaCredential extends UsernamePasswordCredential

再加上captcha属性，及其对应的setter和getter

再修改login-webflow.xml第27行credential对应实体类为com.jadyer.sso.model.UsernamePasswordCaptchaCredential

4、接下来添加校验验证码的流程

继续看，这里我们会发现表单实际的提交等动作是由authenticationViaFormAction处理的

authenticationViaFormAction是被配置在cas-servlet.xml中的第233行

我们要在原有表单处理逻辑的基础上增加验证码，所以就扩展authenticationViaFormAction

创建com.jadyer.sso.authentication.AuthenticationViaCaptchaFormAction extends AuthenticationViaFormAction

在AuthenticationViaCaptchaFormAction中增加一个validateCaptcha()方法用来校验验证码

然后将cas-servlet.xml中的authenticationViaFormAction改为新扩展的AuthenticationViaCaptchaFormAction

同样login-webflow.xml中的三处authenticationViaFormAction改为新扩展的AuthenticationViaCaptchaFormAction

5、最后把messages.properties的一些提示文字改为中文

required.username=必须输入帐号

required.password=必须输入密码

required.captcha=必须输入验证码

error.authentication.captcha.bad=验证码不正确

authenticationFailure.AccountNotFoundException=登录失败–帐号不正确

authenticationFailure.FailedLoginException=登录失败–密码不正确

authenticationFailure.UNKNOWN=未知错误

代码

本文源码下载：（下面两个地址的文件的内容，都是一样的）

Github：https://github.com/v5java/demo-cas-server-web

CSDN下载：http://download.csdn.net/detail/jadyer/8906831

下面是 login-webflow.xml 中的改动部分

<!-- <var name="credential" class="org.jasig.cas.authentication.UsernamePasswordCredential"/> -->
<!-- 新加的用于接收前台表单验证码字段captcha的JavaBean -->
<var name="credential" class="com.jadyer.sso.model.UsernamePasswordCaptchaCredential"/>

<view-state id="viewLoginForm" view="casLoginView" model="credential">
    <binder>
        <binding property="username"/>
        <binding property="password"/>
        <!-- 前台添加表单添加验证码字段captcha -->
        <binding property="captcha"/>
    </binder>
    <on-entry>
        <set name="viewScope.commandName" value="'credential'"/>
    </on-entry>
    <transition on="submit" bind="true" validate="true" to="validateCaptcha">
        <evaluate expression="authenticationViaCaptchaFormAction.doBind(flowRequestContext, flowScope.credential)"/>
    </transition>
</view-state>

<!-- 新添加的校验验证码 -->
<action-state id="validateCaptcha">
    <evaluate expression="authenticationViaCaptchaFormAction.validateCaptcha(flowRequestContext, flowScope.credential, messageContext)"/>
    <transition on="error" to="generateLoginTicket"/>
    <transition on="success" to="realSubmit"/>
</action-state>

<action-state id="realSubmit">
    <evaluate expression="authenticationViaCaptchaFormAction.submit(flowRequestContext, flowScope.credential, messageContext)"/>
    <transition on="warn" to="warn"/>
    <transition on="success" to="sendTicketGrantingTicket"/>
    <transition on="successWithWarnings" to="showMessages"/>
    <transition on="authenticationFailure" to="handleAuthenticationFailure"/>
    <transition on="error" to="generateLoginTicket"/>
</action-state>

下面是扩展的 UsernamePasswordCaptchaCredential.java

package com.jadyer.sso.model;
import org.jasig.cas.authentication.UsernamePasswordCredential;

/**
 * 自定义的接收登录验证码的实体类
 * Created by 玄玉<https://jadyer.cn/> on 2015/07/14 16:28.
 */
public class UsernamePasswordCaptchaCredential extends UsernamePasswordCredential {
    private static final long serialVersionUID = 8317889802836113837L;
    private String captcha;
    /*-- setter和getter略 --*/
}

下面是扩展的 AuthenticationViaCaptchaFormAction.java

package com.jadyer.sso.authentication;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import org.jasig.cas.authentication.Credential;
import org.jasig.cas.web.flow.AuthenticationViaFormAction;
import org.jasig.cas.web.support.WebUtils;
import org.springframework.binding.message.MessageBuilder;
import org.springframework.binding.message.MessageContext;
import org.springframework.util.StringUtils;
import org.springframework.webflow.execution.RequestContext;
import com.jadyer.sso.model.UsernamePasswordCaptchaCredential;

/**
 * 自定义的处理验证码登录逻辑的Action
 * Created by 玄玉<https://jadyer.cn/> on 2015/07/14 16:28.
 */
public class AuthenticationViaCaptchaFormAction extends AuthenticationViaFormAction {
    public final String validateCaptcha(final RequestContext context, final Credential credential, final MessageContext messageContext){
        final HttpServletRequest request = WebUtils.getHttpServletRequest(context);
        HttpSession session = request.getSession();
        String rand = (String)session.getAttribute("rand");
        session.removeAttribute("rand");
        UsernamePasswordCaptchaCredential upc = (UsernamePasswordCaptchaCredential)credential;
        String captcha = upc.getCaptcha();
        System.out.println("获取Session验证码-->" + rand);
        System.out.println("获取表单输入验证码-->" + captcha);
        if(!StringUtils.hasText(rand) || !StringUtils.hasText(captcha)){
            messageContext.addMessage(new MessageBuilder().error().code("required.captcha").build());
            return "error";
        }
        if(captcha.equals(rand)){
            return "success";
        }
        //这段网上这么写的messageContext.addMessage(new MessageBuilder().code("required.captcha").build());
        //实际上这么写是org.springframework.binding.message.INFO级别的，这会导致前台表单无法显示这里的错误信息
        messageContext.addMessage(new MessageBuilder().error().code("error.authentication.captcha.bad").build());
        return "error";
    }
}

下面是 cas-servlet.xml 中的改动部分

<!--
<bean id="authenticationViaFormAction" class="org.jasig.cas.web.flow.AuthenticationViaFormAction"
        p:centralAuthenticationService-ref="centralAuthenticationService"
        p:warnCookieGenerator-ref="warnCookieGenerator"
        p:ticketRegistry-ref="ticketRegistry"/>
 -->
<!-- 新添加的用于校验验证码的Action -->
<bean id="authenticationViaCaptchaFormAction" class="com.jadyer.sso.authentication.AuthenticationViaCaptchaFormAction"
        p:centralAuthenticationService-ref="centralAuthenticationService"
        p:warnCookieGenerator-ref="warnCookieGenerator"
        p:ticketRegistry-ref="ticketRegistry"/>

下面是我的登录成功页 /WEB-INF/view/jsp/jadyer/ui/casGenericSuccess.jsp

<%@ page pageEncoding="UTF-8"%>
<body style="background-color:#CBE0C9;">
    <span style="color:red; font-size:64px; font-weight:bold;">登录成功</span>
</body>

下面是我的登录页 /WEB-INF/view/jsp/jadyer/ui/casLoginView.jsp

<%@ page pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%>

<c:set var="ctx" value="${pageContext.request.contextPath}" scope="session"/>

<!DOCTYPE HTML>
<html>
<head>
    <meta charset="UTF-8"/>
    <title>CAS单点登录系统</title>
    <link rel="icon" type="image/x-icon" href="${ctx}/favicon.ico"/>
    <script type="text/javascript" src="${ctx}/js/jquery-1.10.2.min.js"></script>
    <script type="text/javascript" src="${ctx}/js/jquery-ui-1.10.2.min.js"></script>
    <script type="text/javascript" src="${ctx}/js/cas.js"></script>
    <!--[if lt IE 9]>
        <script src="${ctx}/js/html5shiv-3.7.2.min.js" type="text/javascript"></script>
    <![endif]-->
</head>

<style>
body {background-color: #CBE0C9;}
#msg {padding:20px; margin-bottom:10px;}
#msg.errors {border:1px dotted #BB0000; color:#BB0000; padding-left:100px; background:url(${ctx}/images/error.gif) no-repeat 20px center;}
</style>

<body>
<c:if test="${not pageContext.request.secure}">
    <div id="msg" class="errors">
        <h2>Non-secure Connection</h2>
        <p>You are currently accessing CAS over a non-secure connection.  Single Sign On WILL NOT WORK.  In order to have single sign on work, you MUST log in over HTTPS.</p>
    </div>
</c:if>
<form:form method="post" commandName="${commandName}" htmlEscape="true">
    <!--
    cssClass用于指定表单元素CSS样式名,相当于HTML元素的class属性
    cssStyle用于指定表单元素样式,相当于HTML元素的style属性
    cssErrorClass用于指定表单元素发生错误时对应的样式
    path属性用于绑定表单对象的属性值,它支持级联属性,比如path="user.userName"将调用表单对象getUser.getUserName()绑定表单对象的属性值
     -->
    <form:errors path="*" id="msg" cssClass="errors" element="div" htmlEscape="false"/>
    <input type="hidden" name="lt" value="${loginTicket}"/>
    <input type="hidden" name="execution" value="${flowExecutionKey}"/>
    <input type="hidden" name="_eventId" value="submit"/>
    <table border="9">
        <tr>
            <td>
                <c:if test="${not empty sessionScope.openIdLocalId}">
                    <strong>${sessionScope.openIdLocalId}</strong>
                    <input type="hidden" name="username" value="${sessionScope.openIdLocalId}"/>
                </c:if>
                <c:if test="${empty sessionScope.openIdLocalId}">
                    <form:input tabindex="1" path="username" placeholder="帐号" htmlEscape="true" maxlength="16" size="25"/>
                </c:if>
            </td>
        </tr>
        <tr>
            <td>
                <form:password tabindex="2" path="password" placeholder="密码" htmlEscape="true" maxlength="16" size="25"/>
            </td>
        </tr>
        <tr>
            <td>
                <form:input tabindex="3" path="captcha" placeholder="验证码" htmlEscape="true" maxlength="4" size="15"/>
                <img style="cursor:pointer; vertical-align:middle;" src="captcha.jsp" onClick="this.src='captcha.jsp?time'+Math.random();">
            </td>
        </tr>
        <%--
        <tr>
            <td>
                <input type="checkbox" tabindex="3" name="warn" value="true"/>
                <label for="warn">转向其他站点前提示我</label>
            </td>
        </tr>
        --%>
        <tr>
            <td>
                <input type="submit" tabindex="3" value="登录"/>
            </td>
        </tr>
    </table>
</form:form>
</body>
</html>

最后是用到的用于生成验证码的 /WebRoot/captcha.jsp

<%@ page contentType="image/jpeg; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ page import="java.awt.Color"%>
<%@ page import="java.util.Random"%>
<%@ page import="java.awt.image.BufferedImage"%>
<%@ page import="java.awt.Graphics"%>
<%@ page import="java.awt.Font"%>
<%@ page import="javax.imageio.ImageIO"%>

<%--
这是一个用于生成随机验证码图片的JSP文件
这里contentType="image/jpeg"用来告诉容器：该JSP文件的输出格式为图片格式
登录网站时，通常要求输入随机生成的验证码，这是为了防止有些软件会自动生成破解密码
这些验证码一般都是通过图片显示出来的，并且图片上有很多不规则的线条或者图案来干扰，使得软件不容易识别图案上的验证码
--%>

<%!
/**
 * 定义验证码类型（1--纯数字，2--纯汉字）
 * 这里也支持数字和英文字母组合，但考虑到不好辨认，故注释了这部分代码，详见第69行
 */
int captchaType = 1;

/**
 * 生成给定范围内的随机颜色
 */
Color getRandColor(Random random, int fc, int bc){
    if(fc>255) fc = 255;
    if(bc>255) bc = 255;
    int r = fc + random.nextInt(bc-fc);
    int g = fc + random.nextInt(bc-fc);
    int b = fc + random.nextInt(bc-fc);
    return new Color(r, g, b);
}
%>

<%
//设置页面不缓存
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);

//创建随机类实例
Random random = new Random();
//定义图片尺寸
int width=60*this.captchaType, height=(this.captchaType==1)?20:30;
//创建内存图像
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
//获取图形上下文
Graphics g = image.getGraphics();
//设定背景色
g.setColor(this.getRandColor(random, 200, 250));
//设定图形的矩形坐标及尺寸
g.fillRect(0, 0, width, height);

String sRand = "";
if(this.captchaType == 1){
    //图片背景随机产生50条干扰线作为噪点
    g.setColor(this.getRandColor(random, 160, 200));
    g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
    for(int i=0; i<50; i++){
        int x11 = random.nextInt(width);
        int y11 = random.nextInt(height);
        int x22 = random.nextInt(width);
        int y22 = random.nextInt(height);
        g.drawLine(x11, y11, x11+x22, y11+y22);
    }
    //取随机产生的4个数字作为验证码
    //String str = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
    //String str = "abcdefghkmnpqrstwxyABCDEFGHJKLMNPRSTWXYZ123456789";
    for(int i=0; i<4; i++){
        //String rand = String.valueOf(str.charAt(random.nextInt(62)));
        //String rand = String.valueOf(str.charAt(random.nextInt(49)));
        String rand = String.valueOf(random.nextInt(10));
        sRand += rand;
        g.setColor(this.getRandColor(random, 10, 150));
        //将此数字画到图片上
        g.drawString(rand, 13*i+6, 16);
    }
}else{
    //设定备选汉字
    String base = "/u7684/u4e00/u4e86/u662f/u6211/u4e0d/u5728/u4eba/u4eec/u6709/u6765/u4ed6/u8fd9/u4e0a/u7740" +
                  "/u4e2a/u5730/u5230/u5927/u91cc/u8bf4/u5c31/u53bb/u5b50/u5f97/u4e5f/u548c/u90a3/u8981/u4e0b" +
                  "/u770b/u5929/u65f6/u8fc7/u51fa/u5c0f/u4e48/u8d77/u4f60/u90fd/u628a/u597d/u8fd8/u591a/u6ca1" +
                  "/u4e3a/u53c8/u53ef/u5bb6/u5b66/u53ea/u4ee5/u4e3b/u4f1a/u6837/u5e74/u60f3/u751f/u540c/u8001" +
                  "/u4e2d/u5341/u4ece/u81ea/u9762/u524d/u5934/u9053/u5b83/u540e/u7136/u8d70/u5f88/u50cf/u89c1" +
                  "/u4e24/u7528/u5979/u56fd/u52a8/u8fdb/u6210/u56de/u4ec0/u8fb9/u4f5c/u5bf9/u5f00/u800c/u5df1" +
                  "/u4e9b/u73b0/u5c71/u6c11/u5019/u7ecf/u53d1/u5de5/u5411/u4e8b/u547d/u7ed9/u957f/u6c34/u51e0" +
                  "/u4e49/u4e09/u58f0/u4e8e/u9ad8/u624b/u77e5/u7406/u773c/u5fd7/u70b9/u5fc3/u6218/u4e8c/u95ee" +
                  "/u4f46/u8eab/u65b9/u5b9e/u5403/u505a/u53eb/u5f53/u4f4f/u542c/u9769/u6253/u5462/u771f/u5168" +
                  "/u624d/u56db/u5df2/u6240/u654c/u4e4b/u6700/u5149/u4ea7/u60c5/u8def/u5206/u603b/u6761/u767d" +
                  "/u8bdd/u4e1c/u5e2d/u6b21/u4eb2/u5982/u88ab/u82b1/u53e3/u653e/u513f/u5e38/u6c14/u4e94/u7b2c" +
                  "/u4f7f/u5199/u519b/u5427/u6587/u8fd0/u518d/u679c/u600e/u5b9a/u8bb8/u5feb/u660e/u884c/u56e0" +
                  "/u522b/u98de/u5916/u6811/u7269/u6d3b/u90e8/u95e8/u65e0/u5f80/u8239/u671b/u65b0/u5e26/u961f" +
                  "/u5148/u529b/u5b8c/u5374/u7ad9/u4ee3/u5458/u673a/u66f4/u4e5d/u60a8/u6bcf/u98ce/u7ea7/u8ddf" +
                  "/u7b11/u554a/u5b69/u4e07/u5c11/u76f4/u610f/u591c/u6bd4/u9636/u8fde/u8f66/u91cd/u4fbf/u6597" +
                  "/u9a6c/u54ea/u5316/u592a/u6307/u53d8/u793e/u4f3c/u58eb/u8005/u5e72/u77f3/u6ee1/u65e5/u51b3" +
                  "/u767e/u539f/u62ff/u7fa4/u7a76/u5404/u516d/u672c/u601d/u89e3/u7acb/u6cb3/u6751/u516b/u96be" +
                  "/u65e9/u8bba/u5417/u6839/u5171/u8ba9/u76f8/u7814/u4eca/u5176/u4e66/u5750/u63a5/u5e94/u5173" +
                  "/u4fe1/u89c9/u6b65/u53cd/u5904/u8bb0/u5c06/u5343/u627e/u4e89/u9886/u6216/u5e08/u7ed3/u5757" +
                  "/u8dd1/u8c01/u8349/u8d8a/u5b57/u52a0/u811a/u7d27/u7231/u7b49/u4e60/u9635/u6015/u6708/u9752" +
                  "/u534a/u706b/u6cd5/u9898/u5efa/u8d76/u4f4d/u5531/u6d77/u4e03/u5973/u4efb/u4ef6/u611f/u51c6" +
                  "/u5f20/u56e2/u5c4b/u79bb/u8272/u8138/u7247/u79d1/u5012/u775b/u5229/u4e16/u521a/u4e14/u7531" +
                  "/u9001/u5207/u661f/u5bfc/u665a/u8868/u591f/u6574/u8ba4/u54cd/u96ea/u6d41/u672a/u573a/u8be5" +
                  "/u5e76/u5e95/u6df1/u523b/u5e73/u4f1f/u5fd9/u63d0/u786e/u8fd1/u4eae/u8f7b/u8bb2/u519c/u53e4" +
                  "/u9ed1/u544a/u754c/u62c9/u540d/u5440/u571f/u6e05/u9633/u7167/u529e/u53f2/u6539/u5386/u8f6c" +
                  "/u753b/u9020/u5634/u6b64/u6cbb/u5317/u5fc5/u670d/u96e8/u7a7f/u5185/u8bc6/u9a8c/u4f20/u4e1a" +
                  "/u83dc/u722c/u7761/u5174/u5f62/u91cf/u54b1/u89c2/u82e6/u4f53/u4f17/u901a/u51b2/u5408/u7834" +
                  "/u53cb/u5ea6/u672f/u996d/u516c/u65c1/u623f/u6781/u5357/u67aa/u8bfb/u6c99/u5c81/u7ebf/u91ce" +
                  "/u575a/u7a7a/u6536/u7b97/u81f3/u653f/u57ce/u52b3/u843d/u94b1/u7279/u56f4/u5f1f/u80dc/u6559" +
                  "/u70ed/u5c55/u5305/u6b4c/u7c7b/u6e10/u5f3a/u6570/u4e61/u547c/u6027/u97f3/u7b54/u54e5/u9645" +
                  "/u65e7/u795e/u5ea7/u7ae0/u5e2e/u5566/u53d7/u7cfb/u4ee4/u8df3/u975e/u4f55/u725b/u53d6/u5165" +
                  "/u5cb8/u6562/u6389/u5ffd/u79cd/u88c5/u9876/u6025/u6797/u505c/u606f/u53e5/u533a/u8863/u822c" +
                  "/u62a5/u53f6/u538b/u6162/u53d4/u80cc/u7ec6";
    //图片背景增加噪点
    g.setColor(this.getRandColor(random, 160, 200));
    g.setFont(new Font("Times New Roman", Font.PLAIN, 14));
    for(int i=0; i<6; i++){
        g.drawString("*********************************************", 0, 5*(i+2));
    }
    //设定验证码汉字的备选字体{"宋体", "新宋体", "黑体", "楷体", "隶书"}
    String[] fontTypes = {"/u5b8b/u4f53", "/u65b0/u5b8b/u4f53", "/u9ed1/u4f53", "/u6977/u4f53", "/u96b6/u4e66"};
    //取随机产生的4个汉字作为验证码
    for(int i=0; i<4; i++){
        int start = random.nextInt(base.length());
        String rand = base.substring(start, start+1);
        sRand += rand;
        g.setColor(this.getRandColor(random, 10, 150));
        g.setFont(new Font(fontTypes[random.nextInt(fontTypes.length)], Font.BOLD, 18+random.nextInt(4)));
        //将此汉字画到图片上
        g.drawString(rand, 24*i+10+random.nextInt(8), 24);
    }
}

//将验证码存入SESSION
session.setAttribute("rand", sRand);

//图像生效
g.dispose();
//输出图像到页面
ImageIO.write(image, "PNG", response.getOutputStream());

//若无下面两行代码，则每次请求生成验证码图片时
//尽管不会影响到图片的生成以及验证码的校验，但控制台都会滚动下面的异常
//java.lang.IllegalStateException: getOutputStream() has already been called for this response
out.clear();
out = pageContext.pushBody();
%>

效果图

来源：https://jadyer.cn/2015/07/16/sso-cas-login-captcha/