測試代碼：

Calendar?calendar?=?Calendar.getInstance();

Date?today?=?new?Date();

calendar.setTime(today);

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

Date?yesterday?=?calendar.getTime();

calendar.add(Calendar.DATE,?2);

Date?tomorrow?=?calendar.getTime();

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

System.out.println(sdf.format(yesterday));

System.out.println(sdf.format(today));

System.out.println(sdf.format(tomorrow));

String?code?="201203123412";

SimpleDateFormat?sdf2?=?new?SimpleDateFormat(?"yyyyMMdd"?);

String?dateStr?=?code.substring(0,?8);

String?noStr?=?code.substring(8);

Date?dt?=?sdf2.parse(dateStr);

Long?no?=?Long.parseLong(noStr);

System.out.println(code);

System.out.println(sdf.format(dt));

System.out.println(no);

測試結果：

2016-04-12

2016-04-13

2016-04-14

201203123412

2012-03-12

3412