springmvc拦截器配置

@Override	public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1,   arg2, Exception arg3)			throws Exception {				// TODO Auto-generated method stub			}	@Override	public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1,   arg2, ModelAndView arg3)			throws Exception {				// TODO Auto-generated method stub			}	public boolean preHandle(HttpServletRequest request, HttpServletResponse response,  obj) throws Exception {				return true;	}

public boolean preHandle(HttpServletRequest request, HttpServletResponse response,  obj) throws Exception {				//获取判定登陆的session是否存在		String token = (String) request.getSession().getAttribute("token");		String postId = (String) request.getSession().getAttribute("postId");		if(token == null || token == ""){			String XRequested =request.getHeader("X-Requested-With");			if(" HttpRequest".equals(XRequested)){				response.getWriter().write("IsAjax");			}else{				response.sendRedirect("/m-web/");			}			return false;		}		if(postId == null || postId == ""){			String XRequested =request.getHeader("X-Requested-With");			if(" HttpRequest".equals(XRequested)){				response.getWriter().write("IsAjax");			}else{				response.sendRedirect("/m-web/");			}			return false;		}		return true;	}