private void randomDataCreater() { Random random = new Random(); List<CoCoinRecord> createdCoCoinRecords = new ArrayList<>(); Calendar now = Calendar.getInstance(); Calendar c = Calendar.getInstance(); c.set(2015, 0, 1, 0, 0, 0); c.add(Calendar.SECOND, 1); while (c.before(now)) { for (int i = 0; i < RANDOM_DATA_NUMBER_ON_EACH_DAY; i++) { Calendar r = (Calendar) c.clone(); int hour = random.nextInt(24); int minute = random.nextInt(60); int second = random.nextInt(60); r.set(Calendar.HOUR_OF_DAY, hour); r.set(Calendar.MINUTE, minute); r.set(Calendar.SECOND, second); r.add(Calendar.SECOND, 0); int tag = random.nextInt(TAGS.size()); int expense = random.nextInt(RANDOM_DATA_EXPENSE_ON_EACH_DAY) + 1; CoCoinRecord coCoinRecord = new CoCoinRecord(); coCoinRecord.setCalendar(r); coCoinRecord.setMoney(expense); coCoinRecord.setTag(tag); coCoinRecord.setCurrency("RMB"); coCoinRecord.setRemark("备注:这里显示备注~"); createdCoCoinRecords.add(coCoinRecord); } c.add(Calendar.DATE, 1); } Collections.sort( createdCoCoinRecords, new Comparator<CoCoinRecord>() { @Override public int compare(CoCoinRecord lhs, CoCoinRecord rhs) { if (lhs.getCalendar().before(rhs.getCalendar())) { return -1; } else if (lhs.getCalendar().after(rhs.getCalendar())) { return 1; } else { return 0; } } }); for (CoCoinRecord coCoinRecord : createdCoCoinRecords) { saveRecord(coCoinRecord); } }