Recursive JSON view of an entity with one-to-many relationship in REST controller

Question

I\'m using SpringBoot and JPA to build a REST interface.

Now, I have a strange JSON returned for the list of products fetched from the database. Let\'s say that I h

Answer 1

You're not doing anything wrong (at least at the code level it's rather conceptual) - json serializer just goes like this:

1. Product - serialize it, but wait - there is a category field, so serializer must serialize the category field
2. Category - serialize it, but wait - there is a products field, so serializer must serialize each of the product in the list
3. Product - because your collection contains the product & product contains category it goes in a endless loop untill a timeout.

You must use a view or just skip it.

1. Use @JsonView

2. Use a view as a POJO Return new ProductView that has all fields of product and a reference (category) to new CategoryView (you can end at this point) that has collection of (products) new ProductViewWithoutReferences, and so on

3. Use @JsonIgnore on a collection of products

And as a side note - if it's a @RestController and you're invoking "all-products" then it's a bit unusual to return something else than a list. Wrapping the response in a map is redundant. Many rest clients expect a list when they invoke list() method.

Answer 2

Adding @JsonIgnore worked for me

@OneToMany(mappedBy = "policy")
@JsonIgnore
private List<Payment> payments;

@JeanValjean your are the best

Answer 3

I know it's a bit late, but adding it here in case anybody faces the same problem. Here is another relevant answer I could find which discuss about similar topic

https://stackoverflow.com/a/3359884/6785908

quoting it here

Jackson 1.6 has annotation-based support for handling such parent/child linkage, see http://wiki.fasterxml.com/JacksonFeatureBiDirReferences.

You can of course already exclude serialization of parent link already using most JSON processing packages (jackson, gson and flex-json at least support it), but the real trick is in how to deserialize it back (re-create parent link), not just handle serialization side. Although sounds like for now just exclusion might work for you.

EDIT (April 2012): Jackson 2.0 now supports true identity references, so you can solve it this way also.