Java .lastModified format

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DCagigas
DCagigas 2017-8-4
评论： DCagigas 2017-8-7
Hi everyone,
I am trying to implement a (date,time) check using the ".lastModified" field of a Java file object.
However, I am do not understand the format of the answer:
>> FileObj = java.io.File(getenv('WINDIR'));
>> FileObj.lastModified ans = 1.498033301774000e+12
Are these the milliseconds elapsed since 01.Jan.1970? If so the following code should provide today's date (04.Aug.2017):
>> secs = FileObj.lastModified/1000;
>> [today.y,today.m,today.d,today.h,today.mi,today.s] = datevec(datenum([1970 1 1 0 0 secs]));
>> today
today =
y: 2017
m: 6
d: 21
h: 8
mi: 21
s: 41.774000000001251
Any ideas? Thanks in advance.
Cheers
  1 个评论
DCagigas
DCagigas 2017-8-4
编辑：DCagigas 2017-8-4
My bad...
If I check my "C:Windows" folder it was indeed modified on the 21.Jun.17, at 10:21:41. Which means 2 hours have to be added to the script:
[today.y,today.m,today.d,today.h,today.mi,today.s] = datevec(datenum([1970 1 1 2 0 Millisecs/1000]));
today =
y: 2017
m: 6
d: 21
h: 10
mi: 21
s: 41.774000000004889

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回答（1 个）

Sindhu Yerragunta
编辑：Sindhu Yerragunta 2017-8-7
Hi Dicagigas,
Please refer the following Java documentation
https://docs.oracle.com/javase/7/docs/api/java/io/File.html#lastModified()
The returned milliseconds from lastModified are measured since the epoch (00:00:00 GMT, January 1, 1970). So you need to add GMT difference of your country to the hour argument of 'datenum' function.
For example, for India the time is GMT+5.30, so you need to add an offset of 5 hours 30 minutes.
[today.y,today.m,today.d,today.h,today.mi,today.s] = datevec(datenum([1970 1 1 5 30 secs]));
Hope this answers your query.
-Sindhu
  1 个评论
DCagigas
DCagigas 2017-8-7
Thanks Sindhu for the quick reply.
May I ask you one further question? Are there any files/folders that will keep the "true" data/time even if the user modifies Windows date/time?
Cheers

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