Storing java 8 LocalDate in mongo DB

Question

Using Spring Boot 1.5.4.RELEASE and Mongo driver 3.4.2.

I want to store LocalDate in mongo DB, but I am facing a weird problem:

LocalDate startDate = LocalDate.now();
LocalDate endDate = LocalDate.of(2020,12,01);
System.out.println("---- StartDate : ---"+startDate); 
System.out.println("-----End Date : ----"+endDate);
        
        repository.save(new Person("Mehraj","Malik", startDate, endDate));

Output on console:

---- StartDate : ---2017-08-26

-----End Date : ----2020-12-01

But In MongoDb it is storing incorrect dates.

Following is the json from MongoDb:

"startDate" : ISODate("2017-08-25T18:30:00.000Z"),

"endDate" :ISODate("2020-11-30T18:30:00.000Z")

Also, I have noticed that the stored time is also incorrect according to Indian time.

Why the dates are correct on console but not in MongoDB and how to resolve this problem?

Solution 1

The mongo-java client for a date object returns as instance of java.util.Date.

The problem could possibly be that while you save the startDate and the endDate value, its toString() method would probably use the JVM's default time zone to update the value.

The doc here states that The official BSON specification refers to the BSON Date type as the UTC datetime. and that could be the reason your LocalDateTime attributes were converted to the UTC time zone prior to being saved to the DB.

Also to avoid such confusion would suggest using the bson type timestamp to update date fields.

Solution 2

In the MongoDB Java Driver 3.7 release : http://mongodb.github.io/mongo-java-driver/3.7/whats-new/ we can see that the driver now support LocalDate :

JSR-310 Instant, LocalDate & LocalDateTime support Support for Instant, LocalDate and LocalDateTime has been added to the driver.

Comments

[Guillaume F.]

I dream of the day where specifications won't destroy data based on assumptions, and just store the data as this. Just like Java 8 did with its new date format.