How to convert Google proto timestamp to Java LocalDate?

Asked 4/10, 2018 at 11:24 Answered 9/6, 2022 at 15:7

We need to convert Google Proto buffer time stamp to a normal date. In that circumstance is there any way to convert Google Proto buffer timestamp to a Java LocalDate directly?

Logorrhea answered 4/10, 2018 at 11:24 Comment(5)

Do you mean by Java8 Date LocalDate? Date itself is Java 1 :-) – Bowlin 4/10, 2018 at 11:29

Sorry Its typo. changed the question now @LuCio, – Logorrhea 4/10, 2018 at 11:32

Actually Google Proto Buffer returning com.google.protobuf.Timestamp instance. In that place we need to convert it into LocalDate or what ever its ! – Logorrhea 4/10, 2018 at 11:33

Use Instant.ofEpochSecond(yourTimestamp.getSeconds(), yourTimestamp.getNanos()) and continue from the Instant you get. If in doubt, search for how to convert Instant to LocalDate, it’s described in many places. – Hexane 4/10, 2018 at 12:13

Dear Down-Voter, please leave a criticism along with your vote to explain how this Question is not helpful, constructive, or well-formed. Seems to me to be a perfectly fine Question for Stack Overflow. – Touchhole 4/10, 2018 at 16:40

tl;dr

As a moment in UTC, convert to java.time.Instant. Then apply a time zone to get a ZonedDateTime. Extract the date-only portion as a LocalDate.

One-liner:

Instant
.ofEpochSecond( ts.getSeconds() , ts.getNanos() ) 
.atZone( ZoneId.of( "America/Montreal" ) ) 
.toLocalDate()

Convert

First step is to convert the Timestamp object’s count of seconds and fractional second (nanoseconds) to the java.time classes. Specifically, java.time.Instant. Just like Timestamp, an Instant represents a moment in UTC with a resolution of nanoseconds.

Instant instant =  Instant.ofEpochSecond( ts.getSeconds() , ts.getNanos() ) ;

Determining a date requires a time zone. For any given moment, the date varies around the globe by zone.

Apply a ZoneId to our Instant to get a ZonedDateTime. Same moment, same point on the timeline, different wall-clock time.

ZoneId z = ZoneId( "Pacific/Auckland" ) ; 
ZonedDateTime zdt = instant.atZone( z ) ;

Extract the date-only portion as a LocalDate. A LocalDate has no time-of-day and no time zone.

LocalDate ld = zdt.toLocalDate() ;

Caution: Do not use LocalDateTime class for this purpose, as unfortunately shown in another Answer. That class purposely lacks any concept of time zone or offset-from-UTC. As such it cannot represent a moment, is not a point on the timeline. See class documentation.

Convert

Best to entirely avoid the terribly troublesome legacy date-time classes including Date, Calendar, SimpleDateFormat. But if you must interoperate with old code not yet updated to java.time you can convert back-and-forth. Call new conversion methods added to the old classes.

GregorianCalendar gc = GregorianCalendar.from( zdt ) ;

To represent a date-only value as a GregorianCalendar we must specify a time-of-day and a time zone. You’ll likely want to use the first moment of the day as the time-of-day component. Never assume the first moment is 00:00:00. Anomalies such as Daylight Saving Time mean the first moment might be another time such as 01:00:00. Let java.time determine first moment.

ZonedDateTime firstMomentOfDay = ld.atZone( z ) ;
GregorianCalendar gc = GregorianCalendar.from( firstMomentOfDay ) ;

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes.

Where to obtain the java.time classes?

Java SE 8, Java SE 9, Java SE 10, Java SE 11, and later - Part of the standard Java API with a bundled implementation.
- Java 9 adds some minor features and fixes.
Java SE 6 and Java SE 7
- Most of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport.
Android
- Later versions of Android bundle implementations of the java.time classes.
- For earlier Android (<26), the ThreeTenABP project adapts ThreeTen-Backport (mentioned above). See How to use ThreeTenABP….

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.

Touchhole answered 4/10, 2018 at 16:26 Comment(2)

Thanks for the suggestions @Basil Bourque And can you please help me like how do we convert into Calendar instance too ( java.util.calendar) – Logorrhea 5/10, 2018 at 7:29

@Logorrhea I added “Convert” section. – Touchhole 5/10, 2018 at 15:58

First some heads up: Protobuf's TimeStamp has a higher resolution (Seconds and fractions of seconds) than Java's LocalDate (Days) so you will be loosing some information by converting from TimeStamp to a LocalDate

See this excerpt of TimeStamp's JavaDoc:

A Timestamp represents a point in time independent of any time zone or calendar, represented as seconds and fractions of seconds at nanosecond resolution in UTC Epoch time.

This very same JavaDoc tells us, the value is a representation based on Epoch time, that means we can use Java's LocalDateTime#ofEpochSeconds to convert without loss (because LocalDateTime also stores time) and from there on strip the time to get a LocalDate.

By using a LocalDateTime (em: Local) we can make sure we use the same TimeZone offset as the TimeStamp Class does, which is UTC (thats again from the JavaDoc):

final Timestamp ts1 = Timestamp.newBuilder().setSeconds((60 * 60 * 24) - 1).build();
final Timestamp ts2 = Timestamp.newBuilder().setSeconds((60 * 60 * 24)).build();

final LocalDate ld1 = LocalDateTime.ofEpochSecond(ts1.getSeconds(), ts1.getNanos(), ZoneOffset.UTC).toLocalDate();
final LocalDate ld2 = LocalDateTime.ofEpochSecond(ts2.getSeconds(), ts2.getNanos(), ZoneOffset.UTC).toLocalDate();

System.out.println(ts1 + " = " + ld1);
System.out.println(ts2 + " = " + ld2);

Output

seconds: 86399 = 1970-01-01

seconds: 86400 = 1970-01-02

EDIT after asking for conversion to java.util.Date

Looking at possible constructors for Date and their JavaDoc we find:

Allocates a Date object and initializes it to represent the specified number of milliseconds since the standard base time known as "the epoch", namely January 1, 1970, 00:00:00 GMT.

And because GMT beeing the older Standard for zoned time representation and it is basically UTC +/- 0, this constructor fits our needs:

TimeZone.setDefault(TimeZone.getTimeZone("UTC"));
// making sure the Date objects use UTC as timezone

final Timestamp ts1 = Timestamp.newBuilder().setSeconds((60 * 60 * 24) - 1).build();
final Timestamp ts2 = Timestamp.newBuilder().setSeconds((60 * 60 * 24)).build();

final Date d1 = new Date(ts1.getSeconds() * 1000);
final Date d2 = new Date(ts2.getSeconds() * 1000);

System.out.println(ts1 + " = " + d1);
System.out.println(ts2 + " = " + d2);

Output:

seconds: 86399 = Thu Jan 01 23:59:59 CET 1970

seconds: 86400 = Fri Jan 02 00:00:00 CET 1970

Yevetteyew answered 4/10, 2018 at 12:5 Comment(4)

And more thing like is there any way to convert java.util.Date from proto timestamp instead of LocalDate. – Logorrhea 4/10, 2018 at 13:38

Incorrect. LocalDateTime is exactly the wrong class to be using here. That class cannot represent a moment, as explained in its class documentation. That class represents a range of potential moments along a range of about 26-27 hours (the range of time zones around the globe). Instead, use java.time.Instant to represent a moment in UTC. – Touchhole 4/10, 2018 at 16:8

@BasilBourque I agree that Instant would be more elegant by hiding all the epoch/time zone stuff, though it would not be that much of an explanation to OP of what exactly happens. You are right saying that LocalDateTime can represent a range. But by specifying the time zone offset non of that matters. That would be the same as saying don't use int for numbers between 0 and 10, because int can also be 10.000. – Yevetteyew 5/10, 2018 at 6:44

@BasilBourque and could you please provide an example where my conversion aproach doesn't work? Because I am really open to learn new things and that would be a justification for the downvote and the bold 'incorrect' labeling. Thanks in advance! – Yevetteyew 5/10, 2018 at 6:50

long millis = com.google.protobuf.util.Timestamps.toMillis(protoTimestamp);

LocalDate result = Instant.ofEpochMilli(millis).atZone(ZoneId.systemDefault()).toLocalDate();

see @ https://developers.google.com/protocol-buffers/docs/reference/java/com/google/protobuf/util/Timestamps.html#toMillis-com.google.protobuf.Timestamp-

Lubricous answered 9/6, 2022 at 15:7 Comment(0)

The simplest way to do it is to extract the date from the buffer Timestamp to a String so it can be multiused and then:

Timestamp timestamp;
String sDate1 = timestamp.toString();  
Date date1 = new SimpleDateFormat("dd/MM/yyyy").parse(sDate1);

In case you want to make it a LocalDate you do the following:

Timestamp timestamp;
String sDate1 = timestamp.toString();    
LocalDate localDate = LocalDate.parse(sDate1);

In case you cannot extract the String timestamp and you have Miliseconds you can also create the LocalDate and Date object from that as well, as they both have contractors for it.

    Timestamp timestamp;
    long timeInMilliSeconds = Timestamp.toMillis(timestamp);
    Date currentDate = new Date(timeInMilliSeconds);
    LocalDate date = Instant.ofEpochMilli(timeInMilliSeconds).atZone(ZoneId.systemDefault()).toLocalDate();

Tropaeolin answered 4/10, 2018 at 11:27 Comment(10)

Actually Google Proto Buffer returning com.google.protobuf.Timestamp instance. In that place we need to convert it into LocalDate or what ever its ! – Logorrhea 4/10, 2018 at 11:34

@Logorrhea there has to be a way to make the timestamp a String. After you manage that it is very easy to do whatever you want with it – Tropaeolin 4/10, 2018 at 11:35

Actually google proto buffter timestamp returning the below value seconds: 988221139 nanos: 516000000 – Logorrhea 4/10, 2018 at 11:40

Can you pls check com.google.protobuf.Timestamp class ? @hedgehog – Logorrhea 4/10, 2018 at 11:42

i did and i saw that both toString and getMili exists. i edited my answer, refresh and check @Logorrhea – Tropaeolin 4/10, 2018 at 11:47

@Logorrhea use this and you will be fine: LocalDate date = Instant.ofEpochMilli(timeInMilliSeconds).atZone(ZoneId.systemDefault()).toLocalDate(); – Tropaeolin 4/10, 2018 at 11:49

I'm using com.google.protobuf.Timestamp not com.google.protobuf.util.Timestamps – Logorrhea 4/10, 2018 at 12:3

@Logorrhea just go in here and see the methods that we are telling you. com.google.protobuf.Timestamp , toSeconds(), toNanoSeconds() is there. USE THEM!!! – Tropaeolin 4/10, 2018 at 12:19

@OleV.V. As you can see i have different examples for Date and LocalDate, I only added date for future reference to others getting help from this post. – Tropaeolin 4/10, 2018 at 12:20

According to the documentation there is no getTime method. – Hexane 4/10, 2018 at 12:21

-1

PubsubMessage pubsubMessage = message.getPubsubMessage();
String data = pubsubMessage.getData().toStringUtf8();
//System.out.println(pubsubMessage.getMessageId());
Timestamp timestamp = pubsubMessage.getPublishTime();
//System.out.println(timestamp);
Instant instant =  Instant.ofEpochSecond(timestamp.getSeconds() , 
timestamp.getNanos());
ZoneId z = ZoneId.of("America/Montreal");
ZonedDateTime zdt = instant.atZone(z);
LocalDateTime ldt = zdt.toLocalDateTime();
System.out.println("today's date==> "+ldt.getDayOfMonth());

The above code will definitely work.

Misinform answered 26/3, 2020 at 4:59 Comment(1)

Thanks for wanting to contribute. Are you contributing much that isn’t already in the other answers? It’s more the explanations that we learn from, so if you could add some, please? I believe that your code works. – Hexane 26/3, 2020 at 6:24

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tl;dr

Convert

Convert

About java.time

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