1.如果兩個網站域名的一級域名相同，可以使用cookie和filter實現單點登錄，因為網站有可能（具體看cookie的設置）可以共享cookie。例如：www.bbs.aa.cn www.news.aa.cn。
第一個網站在登錄后，把用戶信息寫到cookie中，當訪問第二個網站時，第二個網站先經過自己的filter，檢查session，如果沒有，查詢cookie，取出用戶信息，放在session中登錄。
public void doFilter(ServletRequest req, ServletResponse resp,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest) req;
if(request.getSession().getAttribute("user")== null){
Cookie[] cs = request.getCookies();
if (cs != null && cs.length > 0) {
for (Cookie c : cs) {
String cName = c.getName();
if (cName.equals("sso")) {
String userName = c.getValue();
request.getSession().setAttribute("user", userName);
}
}
}
}
chain.doFilter(request, resp);
}
2.如果兩個網站域名的一級域名不同，不可以使用cookie和filter實現單點登錄，因為網站不可以共享cookie。例如：www.bbs.cn www.news.cn。
使用cas框架服務實現單點登錄。1.部署cas服務端。2.在服務器端的ticketGrantingTicketCookieGenerator.xml中修改文件。<bean id="ticketGrantingTicketCookieGenerator" class="org.jasig.cas.web.support.CookieRetrievingCookieGenerator"
p:cookieSecure="false"http://使用http協議
p:cookieMaxAge="-1"http://cookie有效時間
p:cookieName="yjwname"http://cookie名稱
p:cookiePath="/" />//項目名稱
3.部署www.bbs.cn www.news.cn服務，在每個客戶端項目中加入casjar包，在web.xml中配置<?xml version="1.0" encoding="UTF-8"?>
<!--
Copyright (c) 2008, Martin W. Kirst
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name of the Martin W. Kirst nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-->
<web-app id="mywebapp" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<display-name>mywebapp</display-name>
<description>
Simple sample, how to use CAS Java Client 3.x.
In this sample exists a public area (/)
and a private area (/protected/*).
</description>
<!-- Sign out not yet implemented -->
<!--
<filter>
<filter-name>CAS Single Sign Out Filter</filter-name>
<filter-class>org.jasig.cas.client.session.SingleSignOutFilter</filter-class>
</filter>
-->
<filter>
<filter-name>CAS Authentication Filter</filter-name>
<filter-class>org.jasig.cas.client.authentication.AuthenticationFilter</filter-class>
<init-param>
<!--cas服務器地址-->
<param-name>casServerLoginUrl</param-name>
<param-value>http://www.service.com:8081/login</param-value>
</init-param>
<init-param>
<!--自己的地址-->
<param-name>serverName</param-name>
<param-value>http://www.bbs.com:8081</param-value>
</init-param>
<init-param>
<param-name>renew</param-name>
<param-value>false</param-value>
</init-param>
<init-param>
<param-name>gateway</param-name>
<param-value>false</param-value>
</init-param>
</filter>
<filter>
<filter-name>CAS Validation Filter</filter-name>
<filter-class>org.jasig.cas.client.validation.Cas20ProxyReceivingTicketValidationFilter</filter-class>
<init-param>
<param-name>casServerUrlPrefix</param-name>
<param-value>http://www.service.com:8081</param-value>
</init-param>
<init-param>
<param-name>serverName</param-name>
<param-value>http://www.bbs.com:8081</param-value>
</init-param>
</filter>
<filter>
<filter-name>CAS HttpServletRequest Wrapper Filter</filter-name>
<filter-class>org.jasig.cas.client.util.HttpServletRequestWrapperFilter</filter-class>
</filter>
<filter>
<filter-name>CAS Assertion Thread Local Filter</filter-name>
<filter-class>org.jasig.cas.client.util.AssertionThreadLocalFilter</filter-class>
</filter>
<!-- ************************* -->
<!-- Sign out not yet implemented -->
<!--
<filter-mapping>
<filter-name>CAS Single Sign Out Filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
-->
<filter-mapping>
<filter-name>CAS Authentication Filter</filter-name>
<!--此URL下的資源都需要驗證登錄-->
<url-pattern>/protected/*</url-pattern>
</filter-mapping>
<filter-mapping>
<filter-name>CAS Validation Filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<filter-mapping>
<filter-name>CAS HttpServletRequest Wrapper Filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<filter-mapping>
<filter-name>CAS Assertion Thread Local Filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<filter-mapping>
<filter-name>CAS Validation Filter</filter-name>
<url-pattern>/proxyCallback</url-pattern>
</filter-mapping>
<!-- *********************** -->
<!-- Sign out not yet implemented -->
<!--
<listener>
<listener-class>org.jasig.cas.client.session.SingleSignOutHttpSessionListener</listener-class>
</listener>
-->
</web-app>
4.啟動服務，這樣就可以實現單點登錄