一个工具类

	
    /**   
     * 得到几天前的时间   
     */   
   
    public static Date getDateBefore(Date d, int day) {    
        Calendar now = Calendar.getInstance();    
        now.setTime(d);    
        now.set(Calendar.DATE, now.get(Calendar.DATE) - day);    
        return now.getTime();    
    }    
   
    /**   
     * 得到几天后的时间   
     */   
        
    public static Date getDateAfter(Date d, int day) {    
        Calendar now = Calendar.getInstance();    
        now.setTime(d);    
        now.set(Calendar.DATE, now.get(Calendar.DATE) + day);    
        return now.getTime();    
    } 

//申明Calendar对象和日期格式对象
   Calendar calendar = Calendar.getInstance();
//DateTimeUtils.getCurrDate();
SimpleDateFormat sdFormate = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
//获取用户升级请求的时间,用于判断**审核的时间有效期是否超过3天.
    String createTime = infoForm.getCreateTime();
    try
    {
       //获取**点击邮件链接时的时间
       Date currentTime = sdFormate.parse(sdFormate.format(calendar.getTime()));
//获取**审批失效的日期
Date createTimeTemp = getDateAfter(sdFormate.parse(createTime),2);
//判断**在审批的时候，是否超过了审批有效日期.如果审批日期失效，转到信息提示页面提示isovertime.
 if(currentTime.compareTo(createTimeTemp) > 0)
  {
      actionMessages.add(
           SupportConstants.COMMON_LINK,
            new ActionMessage(
                SupportConstants.COMMON_RETURN,
                   "/support/index.jsp"));
                    actionMessages.add(
                 SupportConstants.COMMON_MESSAGE,
                     new ActionMessage    ("register.approve.prompt.info.isovertime"));
       return super.forwardMessagePage(request, mapping, actionMessages);
            }
        }
        catch (ParseException e)
        {
            e.printStackTrace();
        }