Java中Calendar/SimpleDateFormat/Date常用方法总结

 1 //获取当前时刻yyyy-MM-dd HH:mm:ss

 2 Calendar calendar = Calendar.getInstance();

 3 SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");// 设置日期格式

 4 String now = sdf.format(calendar.getTime());

 5 System.out.println(now);

 6 

 7 //获取当前时刻yyyy-MM-dd

 8 Calendar calendar = Calendar.getInstance();

 9 SimpleDateFormat sdf1 = new SimpleDateFormat("yyyy-MM-dd");// 设置日期格式

10 String now1 = sdf1.format(calendar.getTime());

11 System.out.println(now1);

12 

13 //获取当前时刻yyyy-MM

14 Calendar calendar = Calendar.getInstance();

15 SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy-MM");// 设置日期格式

16 String now2 = sdf2.format(calendar.getTime());

17 System.out.println(now2);

18 

19 //获取当前时刻,年月日

20 Calendar calendar = Calendar.getInstance();

21 int year = calendar.get(Calendar.YEAR);

22 int month = calendar.get(Calendar.MONTH) + 1;

23 int day = calendar.get(Calendar.DAY_OF_MONTH);

24 System.out.println(year + "-" + month + "-" + day);

25 

26 //获取当前时刻时间戳

27 Calendar calendar = Calendar.getInstance();

28 long ts = calendar.getTimeInMillis();

29 System.out.println(ts);

30 

31 //获取上个月yyyy-MM

32 Calendar calendar = Calendar.getInstance();

33 calendar.add(Calendar.MONTH, -1);

34 String lastMonth = new SimpleDateFormat("yyyy-MM").format(calendar.getTime());

35 System.out.println(lastMonth);

36 

37 //获取昨天yyyy-MM-dd

38 Calendar calendar = Calendar.getInstance();

39 calendar.add(Calendar.DATE, -1);

40 String yesterday = new SimpleDateFormat("yyyy-MM-dd").format(calendar.getTime());

41 System.out.println(yesterday);

42 

43 //将指定年月日时分秒转换成时间戳

44 SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

45 Date date = simpleDateFormat.parse("2015-05-01 00:00:00");

46 long ts1 = date.getTime();

47 System.out.println(ts1);

48 //或者

49 Calendar calendar = Calendar.getInstance();

50 calendar.set(2015, 4, 1, 0, 0, 0);     //此处4即代表5月

51 long ts2 = calendar.getTimeInMillis();

52 System.out.println(ts2);

53 

54 //将指定时间戳转化为年月日时分秒

55 SimpleDateFormat format = new SimpleDateFormat( "yyyy-MM-dd HH:mm:ss" );

56 long ts = 1234567899L;

57 String date = format.format(ts);

58 Date date1 = format.parse(date);

59 System.out.println("Format To String(Date):" + date);

60 System.out.println("Format To Date:" + date1);