CAS client 端添加初始化参数传到server端

1. 修改client 端web应用的web.xml，如下：

<filter>
		<filter-name>CAS Authentication Filter</filter-name>
		<filter-class>org.jasig.cas.client.authentication.AuthenticationFilter</filter-class>
		<init-param>
			<param-name>casServerLoginUrl</param-name>
			<!-- CAS服务端地址-->
			<param-value>http://192.168.104.123:8080/cas/login</param-value>
		</init-param>
		<init-param>
			<param-name>service</param-name>
			<!-- 本地地址-->
			<param-value>http://192.168.104.101:8080/*</param-value>
		</init-param>
		<init-param>
			<param-name>renew</param-name>
			<param-value>false</param-value>
			<!-- 这个如果为true 每次登录子系统都要验证，就不能实现登陆一次，可以访问其他子系统的需求 -->
		</init-param>
		<init-param>
			<param-name>webRootKey</param-name>
			<param-value>test</param-value>
		</init-param>
	</filter>

其中webRootKey参数为client添加的初始化参数，想传到server端

2. 修改org.jasig.cas.client.authentication.AuthenticationFilter.java如下：
添加属性webRootKey

/**
	 * the web app root key
	 */
	private String webRootKey;

，
提供set方法

public final  void setWebRootKey(final String webRootKey){
    	this.webRootKey = webRootKey;
    }

修改initInternal方法，添加

setWebRootKey(getPropertyFromInitParams(filterConfig, "webRootKey", null));
            log.trace("Loaded WebRootKey parameter: " + this.webRootKey);

修改init方法，添加

 CommonUtils.assertNotNull(this.webRootKey, "webRootKey cannot be null.");

3 自定义Credentials类继承UsernamePasswordCredentials，内容如下：

private static final long serialVersionUID = 179318697348051866L;
    
    /** the web root key */
    private String webRootKey;

	public String getWebRootKey() {
		return webRootKey;
	}

	public void setWebRootKey(String webRootKey) {
		this.webRootKey = webRootKey;
	}

4 修改自定义验证类（继承 AbstractJdbcUsernamePasswordAuthenticationHandler）的authenticateUsernamePasswordInternal方法如下：

FinalUserCredentials finalUserCredentials = (FinalUserCredentials) credentials;
		String username = finalUserCredentials.getUsername();
		String password = finalUserCredentials.getPassword();
		
		/** get web root key */
		String webRootKey = finalUserCredentials.getWebRootKey();

既可以获得webRootKey扩展参数。