Date、String、Calendar類型之間的轉化

1.Calendar 轉化 String

  //獲取當前時間的具體情況,如年,月,日,week,date,分,秒等

  Calendar calendat = Calendar.getInstance();

  SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

  String dateStr = sdf.format(calendar.getTime());

 

2.String 轉化Calendar

  String str="2010-5-27";

  SimpleDateFormat sdf= new SimpleDateFormat("yyyy-MM-dd");

  Date date =sdf.parse(str);

  Calendar calendar = Calendar.getInstance();

  calendar.setTime(date);

 

3.Date 轉化String

  SimpleDateFormat sdf= new SimpleDateFormat("yyyy-MM-dd");

  String dateStr=sdf.format(new Date());

 

4.String 轉化Date

  String str="2010-5-27";

  SimpleDateFormat sdf= new SimpleDateFormat("yyyy-MM-dd");

  Date birthday = sdf.parse(str);

 

5.Date 轉化Calendar

  Calendar calendar = Calendar.getInstance();

  calendar.setTime(new java.util.Date());

 

6.Calendar轉化Date

  Calendar calendar = Calendar.getInstance();

  java.util.Date date =calendar.getTime();

 

下面有個例子，插入oralce表類型為DATE的數據

 

SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd HHmmss");

String date = sdf.format(new Date());

-----------------------------------------

String sql = "Insert into SM_SEND (*****************) " +

"values (*******************************

"',1," + "to_date('" +date+ "','YYYY-MM-DD HH24:MI:SS')" +

"," + "to_date('" +date+ "','YYYY-MM-DD HH24:MI:SS')" +

",0,null,null,null,null,null,null,null)";

注：date轉calendar時使用calendar.setTime();

有時當setTime的參數格式問題會導致轉換異常

 

實例 1

/** * 獲取上月十五日凌晨時間 * @author: WY * @rise: */
    public static String previousMonth15() throws ParseException{ Calendar calendar = Calendar.getInstance(); calendar.set(Calendar.MONTH, calendar.get(Calendar.MONTH)-1); calendar.set(Calendar.DAY_OF_MONTH,15); calendar.set(Calendar.HOUR_OF_DAY, 0); calendar.set(Calendar.SECOND,0); calendar.set(Calendar.MINUTE,0); Date strDateTo = calendar.getTime(); SimpleDateFormat sdf= new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); return sdf.format(strDateTo); }