自动根据单点登录系统的信息设置本系统的用户信息 filter

package com.newlifegroup.filter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;


import org.jasig.cas.client.validation.Assertion;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;

import com.newlifegroup.casClient.service.CasClientService;
import com.newlifegroup.casClient.service.CasClientServiceImpl;
import com.newlifegroup.casClient.service.bean.UserBean;

/**
 * 自动根据单点登录系统的信息设置本系统的用户信息
 *
 * @author 刘研
 *
 */

public class AutoSetUserAdapterFilter implements Filter {
	/**
	 * Default constructor. 
	 */
	public AutoSetUserAdapterFilter() {
	}

	public void destroy() {
		// TODO Auto-generated method stub

	}

	/**
	 * 过滤逻辑：首先判断单点登录的账户是否已经存在本系统中，
	 * 如果不存在使用用户查询接口查询出用户对象并设置在Session中
	 * @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain)
	 */
	
	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {

		HttpServletRequest httpRequest = (HttpServletRequest) request;
		
		// _const_cas_assertion_是CAS中存放登录用户名的session标志
		Object object = httpRequest.getSession().getAttribute("_const_cas_assertion_");
		if (object != null) {
			Assertion assertion = (Assertion) object;
			String loginName = assertion.getPrincipal().getName();
			UserBean user=(UserBean) httpRequest.getSession().getAttribute("user");
			
			// 第一次登录系统
			if (user == null) {
				
				WebApplicationContext wct = WebApplicationContextUtils.getWebApplicationContext(httpRequest
						.getSession().getServletContext());
				CasClientService casClientService=(CasClientServiceImpl)wct.getBean("casClientServiceImpl");
				// 保存用户信息到Session
				user=casClientService.findUserByLoginName(loginName);
				httpRequest.getSession().setAttribute("user", user);
			}
			
		}
		chain.doFilter(request, response);
		
		
		
		
	}

	public void init(FilterConfig arg0) throws ServletException {
		// TODO Auto-generated method stub

	}

}