获得HttpServletRequest 和HttpSession对象

package org.jeecgframework.core.util;  

import java.util.HashMap;  
import java.util.Map;  
import javax.servlet.http.HttpServletRequest;  
import javax.servlet.http.HttpSession;  
import org.springframework.web.context.request.RequestContextHolder;  
import org.springframework.web.context.request.ServletRequestAttributes;  

/** 
* @ClassName: ContextHolderUtils  
* @Description: TODO(上下文工具类)  
* @author  张代浩  
* @date 2012-12-15 下午11:27:39  
* 
*/  
public class ContextHolderUtils {  
/** 
* SpringMvc下获取request 
*  
* @return 
*/  
public static HttpServletRequest getRequest() {  
HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();  
return request;  

    }  

/** 
* SpringMvc下获取session 
*  
* @return 
*/  
public static HttpSession getSession() {  
HttpServletRequest request = getRequest();  
String tempSessionId = request.getParameter("sessionId");  
HttpSession session = request.getSession();  
String sessionId = session.getId();  
if(StringUtil.isNotEmpty(tempSessionId) && !tempSessionId.equals(sessionId)){  
sessionId = tempSessionId;  
if(sessionMap.containsKey(sessionId)){  
session = sessionMap.get(sessionId);  
            }  
        }  
if(!sessionMap.containsKey(sessionId)){  
sessionMap.put(sessionId, session);  
        }  
return session;  
    }  


private static final Map<String, HttpSession> sessionMap = new HashMap<String, HttpSession>();  

public static HttpSession getSession(String sessionId){  
HttpSession session = sessionMap.get(sessionId);  
return session == null ? getSession() : session;  
    }  

public static void removeSession(String sessionId){  
if(sessionMap.containsKey(sessionId)){  
sessionMap.remove(sessionId);  
        }  
    }