在java中计算月份和时差？
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【中文标题】在java中计算月份和时差？【英文标题】：Calculate month and time difference in java? 【发布时间】：2017-09-24 19:34:27 【问题描述】：我有这个代码来计算月份和时差，但是这个代码给出了错误的输出 当我测试这段代码时，它计算的 3 个月甚至实际月差为 1，并且在时间相同的情况下，请帮忙看看这段代码的问题在哪里......
public static void updateLinkDownTimeDate(ObjectId TimeDateId, TimeDatePojo TimeDatePojo)
try
List<DBObject> array = new ArrayList<>();
BasicDBObject match = new BasicDBObject();
match.put("_id", TimeDateId);
DBCollection collection = new MongoSetup().getDBCollection("TimeDate");
DBObject obj = TimeDatePojo.bsomFromPojo();
String newId = (String) obj.get("linkId");
SimpleDateFormat dates = new SimpleDateFormat("dd-MM-yyyy");
String startDate = dates.format(obj.get("startDate"));
String endDate = dates.format(obj.get("endDate"));
Date SD = dates.parse(startDate);
Date ED = dates.parse(endDate);
Calendar cal = Calendar.getInstance();
cal.setTime(SD);
int month = cal.get(Calendar.MONTH);
int year = cal.get(Calendar.YEAR);
String startTime = (String) obj.get("startTime"); //present start time
SimpleDateFormat forms = new SimpleDateFormat("dd-MM-yyyy");
SimpleDateFormat form = new SimpleDateFormat("HH:mm:ss");
Calendar currentStartDateCalendar = Calendar.getInstance();
currentStartDateCalendar.setTime(SD);
int currentSDate = currentStartDateCalendar.get(Calendar.DATE);
int currentStartMonth = currentStartDateCalendar.get(Calendar.MONTH);
int currentStartYear = currentStartDateCalendar.get(Calendar.YEAR);
Date STs = form.parse(startTime);
Calendar presentStartTime = Calendar.getInstance();
presentStartTime.setTime(STs);
int currentHour = presentStartTime.get(Calendar.HOUR);
int currentMin = presentStartTime.get(Calendar.MINUTE);
int currentSec = presentStartTime.get(Calendar.SECOND);
currentStartDateCalendar.set(currentStartYear, currentStartMonth, currentSDate, currentHour, currentMin, currentSec);
Date PSDate = currentStartDateCalendar.getTime();
String endTime = (String) obj.get("endTime"); //present end time
Date ETs = form.parse(endTime);
Calendar currentEndDateCalender = Calendar.getInstance();
currentEndDateCalender.setTime(ED);
int currentEDate = currentEndDateCalender.get(Calendar.DATE);
int currentEndMonth = currentEndDateCalender.get(Calendar.MONTH);
int currentEYear = currentEndDateCalender.get(Calendar.YEAR);
Calendar presentEndTime = Calendar.getInstance();
presentEndTime.setTime(ETs);
int currentEndHour = presentEndTime.get(Calendar.HOUR);
int currentEndMin = presentEndTime.get(Calendar.MINUTE);
int currentEndSec = presentEndTime.get(Calendar.SECOND);
currentEndDateCalender.set(currentEYear, currentEndMonth, currentEDate, currentEndHour, currentEndMin, currentEndSec);
Date PEDate = currentEndDateCalender.getTime();
BasicDBObject getSavedDate = new BasicDBObject();
getSavedDate.append("_id", linkDownTimeDateId);
getSavedDate.append("linkId", newId);
DBObject seeSaved = collection.findOne(getSavedDate);
Date savedSDate = (Date) seeSaved.get("startDate");
Date savedEDate = (Date) seeSaved.get("endDate");
String savedStartTime = (String) seeSaved.get("startTime");
String savedEndTime = (String) seeSaved.get("endTime");
Date SSD = null;
Date SED = null;
if (savedSDate.compareTo(SD) == 0 && savedEDate.compareTo(ED) == 0)
Calendar saveStartTimeCalendar = Calendar.getInstance();
saveStartTimeCalendar.setTime(savedSDate);
int savedYear = saveStartTimeCalendar.get(Calendar.YEAR);
int savedMonth = saveStartTimeCalendar.get(Calendar.MONTH);
int savedDate = saveStartTimeCalendar.get(Calendar.DATE);
Date SSTs = form.parse(savedStartTime);
Calendar savedStartTimeCal = Calendar.getInstance();
savedStartTimeCal.setTime(SSTs);
int hour = savedStartTimeCal.get(Calendar.HOUR);
int mins = savedStartTimeCal.get(Calendar.MINUTE);
int secs = savedStartTimeCal.get(Calendar.SECOND);
saveStartTimeCalendar.set(savedYear, savedMonth, savedDate, hour, mins, secs);
SSD = saveStartTimeCalendar.getTime();
Calendar saveEndTimeCalendar = Calendar.getInstance();
saveStartTimeCalendar.setTime(savedEDate);
int savedEndYear = saveEndTimeCalendar.get(Calendar.YEAR);
int savedEndMonth = saveEndTimeCalendar.get(Calendar.MONTH);
int savedEndDates = saveEndTimeCalendar.get(Calendar.DATE);
Date ESTs = form.parse(savedEndTime);
Calendar savedEndTimeCal = Calendar.getInstance();
savedEndTimeCal.setTime(ESTs);
int endhour = savedStartTimeCal.get(Calendar.HOUR);
int endmins = savedStartTimeCal.get(Calendar.MINUTE);
int endsecs = savedStartTimeCal.get(Calendar.SECOND);
saveEndTimeCalendar.set(savedEndYear, savedEndMonth, savedEndDates, endhour, endmins, endsecs);
SED = saveEndTimeCalendar.getTime();
else if (savedSDate.compareTo(SD) == -1 || savedEDate.compareTo(ED) == -1)
Calendar saveStartTimeCalendar = Calendar.getInstance();
saveStartTimeCalendar.setTime(SD);
int savedYear = saveStartTimeCalendar.get(Calendar.YEAR);
int savedMonth = saveStartTimeCalendar.get(Calendar.MONTH);
int savedDate = saveStartTimeCalendar.get(Calendar.DATE);
Date SSTs = form.parse(savedStartTime);
Calendar savedStartTimeCal = Calendar.getInstance();
savedStartTimeCal.setTime(SSTs);
int hour = savedStartTimeCal.get(Calendar.HOUR);
int mins = savedStartTimeCal.get(Calendar.MINUTE);
int secs = savedStartTimeCal.get(Calendar.SECOND);
saveStartTimeCalendar.set(savedYear, savedMonth, savedDate, hour, mins, secs);
SSD = saveStartTimeCalendar.getTime();
Calendar saveEndTimeCalendar = Calendar.getInstance();
saveStartTimeCalendar.setTime(ED);
int savedEndYear = saveEndTimeCalendar.get(Calendar.YEAR);
int savedEndMonth = saveEndTimeCalendar.get(Calendar.MONTH);
int savedEndDates = saveEndTimeCalendar.get(Calendar.DATE);
Date ESTs = form.parse(savedEndTime);
Calendar savedEndTimeCal = Calendar.getInstance();
savedEndTimeCal.setTime(ESTs);
int endhour = savedStartTimeCal.get(Calendar.HOUR);
int endmins = savedStartTimeCal.get(Calendar.MINUTE);
int endsecs = savedStartTimeCal.get(Calendar.SECOND);
saveEndTimeCalendar.set(savedEndYear, savedEndMonth, savedEndDates, endhour, endmins, endsecs);
SED = saveEndTimeCalendar.getTime();
List<DBObject> lists = (List<DBObject>) seeSaved.get("linkDownTime");
int down = 0;
for (DBObject dating : lists)
down = (int) dating.get("downTime"); //saved down time
String startHour = "00:00:00";
String endHour = "24:00:00";
long minutesInOneDay = 1440;
int numberOfDays = 0;
long dateDifference = 0l;
int totalCalculatedMins = 0;
try
dateDifference = ED.getTime() - SD.getTime();
long days = dateDifference / (24 * 60 * 60 * 1000);
numberOfDays = (int) days;
if (numberOfDays == 0)
int min = (int) minutesInOneDay;
SimpleDateFormat format2 = new SimpleDateFormat("HH:mm:ss");
Date parsedStartTime = format2.parse(startTime);
Date parsedEndTime = format2.parse(endTime);
Date parsedOriginalStartHour = format2.parse(startHour);
Date parsedOriginalEndHour = format2.parse(endHour);
long excludeStartTime = parsedOriginalEndHour.getTime() - parsedStartTime.getTime();
long excludedStartMins = minutesInOneDay - (excludeStartTime / (60 * 1000));
int excludedMins = (int) excludedStartMins;
long excludeEndTime = parsedEndTime.getTime() - parsedOriginalStartHour.getTime();
long excludeEndMins = 1440 - (excludeEndTime / (60 * 1000));
int excludeMins2 = (int) excludeEndMins;
long calculation = min - excludedMins - excludeMins2;
totalCalculatedMins = (int) calculation;
else
long minuetes = (minutesInOneDay * numberOfDays);
int min = (int) minuetes;
SimpleDateFormat format2 = new SimpleDateFormat("HH:mm:ss");
Date parsedStartTime = format2.parse(startTime);
Date parsedEndTime = format2.parse(endTime);
Date parsedOriginalStartHour = format2.parse(startHour);
Date parsedOriginalEndHour = format2.parse(endHour);
long excludeStartTime = parsedOriginalEndHour.getTime() - parsedStartTime.getTime();
long excludedStartMins = excludeStartTime / (60 * 1000);
int excludedMins = (int) excludedStartMins;
long excludeEndTime = parsedEndTime.getTime() - parsedOriginalStartHour.getTime();
long excludeEndMins = 1440 + (-(excludeEndTime / (60 * 1000)));
int excludeMins2 = (int) excludeEndMins;
long calculation = min + excludedMins - excludeMins2;
totalCalculatedMins = (int) calculation;
catch (Exception e)
System.out.println("Exception being :-" + e);
DBObject sub = new BasicDBObject();
sub.put("linkId", newId);
sub.put("year", year);
sub.put("month", month);
sub.put("downTime", totalCalculatedMins);
array.add(sub);
obj.put("linkDownTime", array);
BasicDBObject update = new BasicDBObject();
update.put("$set", obj);
collection.update(match, update, true, false);
BasicDBObject newQuery = new BasicDBObject("linkId", obj.get("linkId"))
.append("startDate", obj.get("startDate"))
.append("endDate", obj.get("endDate"));
DBObject findNewQuery = collection.findOne(newQuery);
DBCollection collection2 = new MongoSetup().getDBCollection("linkTotalDownTime");
List<DBObject> list = (List<DBObject>) findNewQuery.get("linkDownTime");
for (DBObject data : list)
String linkId = (String) data.get("linkId");
int years = (int) data.get("year");
int months = (int) data.get("month");
int downTime = (int) data.get("downTime"); // current downTime
BasicDBObject look = new BasicDBObject();
look.append("linkID", linkId).append("Year", year).append("month", month);
DBObject findData = collection2.findOne(look);
int dataget = (int) findData.get("totaldownTime"); //totaldowntime
int finalValue = 0;
int finalTotalValue = 0;
if (collection2.count() == 1)
if (PSDate.compareTo(SSD) == 1)
if (downTime > down)
finalValue = down - downTime;
finalTotalValue = (int) (dataget - finalValue);
else if (down > downTime)
finalValue = down - downTime;
finalTotalValue = (int) (dataget - finalValue);
else if (PSDate.compareTo(SSD) == -1)
if (downTime > down)
finalValue = downTime - down;
finalTotalValue = (int) (dataget + finalValue);
else if (down > downTime)
finalValue = down - downTime;
finalTotalValue = (int) (dataget + finalValue);
else if (PEDate.compareTo(SED) == 1)
if (downTime > down)
finalValue = downTime - down;
finalTotalValue = (int) (dataget + finalValue);
else if (down > downTime)
finalValue = down - downTime;
finalTotalValue = (int) (dataget + finalValue);
else if (PEDate.compareTo(SED) == -1)
if (downTime > down)
finalValue = downTime - down;
finalTotalValue = (int) (dataget - finalValue);
else if (down > downTime)
finalValue = down - downTime;
finalTotalValue = (int) (dataget - finalValue);
else if (collection2.count() > 1)
if (PSDate.compareTo(SSD) == 1)
if (downTime > down)
finalValue = downTime - down;
finalTotalValue = (int) (dataget - finalValue);
else if (down > downTime)
finalValue = down - downTime;
finalTotalValue = (int) (dataget - finalValue);
else if (PSDate.compareTo(SSD) == -1)
if (downTime > down)
finalValue = downTime - down;
finalTotalValue = (int) (dataget + finalValue);
else if (down > downTime)
finalValue = down - downTime;
finalTotalValue = (int) (dataget + finalValue);
else if (PEDate.compareTo(SED) == 1)
if (downTime > down)
finalValue = downTime - down;
finalTotalValue = (int) (dataget + finalValue);
else if (down > downTime)
finalValue = down - downTime;
finalTotalValue = (int) (dataget + finalValue);
else if (PEDate.compareTo(SED) == -1)
if (downTime > down)
finalValue = downTime - down;
finalTotalValue = (int) (dataget - finalValue);
else if (down > downTime)
finalValue = down - downTime;
finalTotalValue = (int) (dataget - finalValue);
BasicDBObject update_two = new BasicDBObject();
update_two.put("linkID", linkId);
update_two.put("Year", years);
update_two.put("month", months);
update_two.put("totaldownTime", finalTotalValue);
collection2.update(findData, update_two, true, false);
System.out.println("Updated Successfully ...");
catch (Exception ex)
ex.printStackTrace();
【问题讨论】：
您应该遵循@LukeJanyga 的建议并使用java.time 框架。停止使用原始 java.util.Date 对象并开始使用 LocalDateTime、LocalDate、LocalTime 等。 你能告诉我代码中的错误在哪里，为什么它没有给出正确的月差和时差？ 我现在没有空来看看你的代码。对您来说最好的方法是切换到 java 时间：因为您可以更快地工作，从而减少代码行数。 看看java time javadoc和this article。 【参考方案1】：请使用目前 Java 的标准 JSR-310（称为 ThreeTen）。它提供了像 Duration 或 ChronoUnit 这样的类，其中包含所有必要的工具。
例如ChronoUnit.MONTHS.between() 将计算两个日期之间的跨度（以月为单位）
【讨论】：
【参考方案2】：String calculateTime(String strDate) throws ParseException
String result = "";
SimpleDateFormat dateFormat = new SimpleDateFormat("ddMMHHmm");
Date currDate = new Date();
String date = dateFormat.format(currDate);
currDate = dateFormat.parse(date);
Date postDate = dateFormat.parse(strDate);
//calculate day diff
long timeDiff = currDate.getTime() - postDate.getTime();
long daysDiff = TimeUnit.MILLISECONDS.toDays(timeDiff);
Calendar calendar = GregorianCalendar.getInstance();
calendar.setTime(postDate);
if (daysDiff == 1)
result = "yesterday";
result = result + " at " + getHour(calendar.get(Calendar.HOUR)) + ":"
+ setPrefix(calendar.get(Calendar.MINUTE))+ " " + getAM_PM(calendar.get(Calendar.AM_PM));
else if (daysDiff > 1)
result = calendar.get(Calendar.DATE) + " " + getMonthForInt(calendar.get(Calendar.MONTH));
result = result + " at " + getHour(calendar.get(Calendar.HOUR)) + ":"
+ setPrefix(calendar.get(Calendar.MINUTE)) + " " + getAM_PM(calendar.get(Calendar.AM_PM));
else
long minDiff = TimeUnit.MILLISECONDS.toMinutes(timeDiff);
if (minDiff == 0)
result = "just now";
else if (minDiff < 60)
if (minDiff == 1)
result = minDiff + " min ago";
else if(minDiff > 1)
result = minDiff + " mins ago";
else
long hourDiff = TimeUnit.MILLISECONDS.toHours(timeDiff);
if (hourDiff == 1)
result = hourDiff + " hr ago";
else if(hourDiff > 1)
result = hourDiff + " hrs ago";
return result;
【讨论】：
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