Java 日期处理

//查询条件日期时间段为空的话默认设置本月一号到明天（0时），查询时小于明天

String beginDate=request.getParameter("beginDate");
   String endDate=request.getParameter("endDate");

if(!CommonMethod.isNull(beginDate)){
    qm.setBeginDate(DateUtil.parseStringToDate(beginDate, "yyyy-MM-dd"));
   }else{
    qm.setBeginDate(DateUtil.parseStringToDate(DateUtil.getFormatDateStr(new Date(), "yyyy-MM")+"-01", "yyyy-MM-dd"));
   }
   if(!CommonMethod.isNull(endDate)){
    qm.setEndDate(DateUtil.getNextNDayDate(DateUtil.parseStringToDate(endDate, "yyyy-MM-dd"),1));
   }else{
    qm.setEndDate(DateUtil.getNextNDayDate(new Date(), 1));
   }

用到函数：

/**
  * @功能描述:將字符串轉換為日期
  * @param dateStr
  * @return
  * @创建时间 2008-7-13
  * @author Administrator
  */
 public static Date parseStringToDate(String dateStr, String formate)
   throws Exception {
  try {
   SimpleDateFormat sdf = getSimpleDateFormat(formate);
   return sdf.parse(dateStr);
  } catch (Exception ex) {
   return null;
  }
 }

/**
  * 获取当前日期
  * @return
  * @throws Exception
  */
 public static Date getCurrentDate() throws Exception {
  Date currTime = new Date(System.currentTimeMillis());
  return currTime;
 }
 /**
  * 获取date日期的n天后的日期
  * @param date
  * @param day
  * @return
  */
 public static Date getNextNDayDate(Date date, int day){
  Calendar c=Calendar.getInstance();
  c.setTime(date);
  c.add(Calendar.DATE, day);
//  long d = date.getTime();
//  long n = day * 24 * 60 * 60 * 1000;
//  d = d + n;
  return c.getTime();
 }

/**   * @功能描述:获取指定格式的字符串   * @return   * @创建时间 2008-7-26   * @author beedoor   */  public static String getFormatDateStr(Object obj, String format)    throws Exception {   Date d = null;   SimpleDateFormat sdf = getSimpleDateFormat(format);   if (obj instanceof String) {    d = sdf.parse(obj.toString());   } else if (obj instanceof Date) {    d = (Date) obj;

  }   if (null != d) {    return sdf.format(d);   }

  return "";  }