JPA @OrderBy Annotation - Ordering Strings

Question

I am using the @OrderBy annotation in my entity class to sort a collection that is eagerly fetched. The column I am ordering on is of type String. However, in some instances, these strings may contain numbers. How do I ensure that the OrderBy annotation will order numbers stored as strings in their numeric order instead of 1,10,2,3,4,5,6,7,8,9 ?

score 1 · Answer 1 · edited May 23 '17 at 12:31

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@OrderBy will sort according to the database since it will be part of your SQL query. Using @SortComparator with a custom comparator will achieve your result. You can also consider combining the 2 as well (@OrderBy so that you return in some consistent order from the database, then the @SortComparator for the desired order)

Not sure if you have an idea of how to write the comparator, but this question is a start to that.

edited May 23 '17 at 12:31

Community

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answered Apr 24 '14 at 08:29

Shiraaz.M

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Where `@SortComparable` come from? – wypieprz Apr 24 '14 at 10:37
Typo, it's meant to be @SortComparator .. updating my answer for this – Shiraaz.M Apr 24 '14 at 10:48

score 0 · Answer 2 · edited May 23 '17 at 12:07

You may want to consider storing the strings as 0-prefix to a fixed maximum length, eg: 001, 023, 234 etc. Ordering will then work correctly using the normal string alpha comparison.

See Ordering results by computed value in Hibernate for a JPA specific implementation way of achiveing close to the same thing.

Another option is to store your collection in a TreeSet with a custom comparator.

JPA @OrderBy Annotation - Ordering Strings

2 Answers2