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);