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Editorial Team
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Asked: 2026-06-14T21:47:22+00:00

I’m trying to implement the HAL standard for JSON in a JAX-RS service. My

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I’m trying to implement the HAL standard for JSON in a JAX-RS service. My project consists of Users containing many Projects containing many Nodes containing a variety of data and pointers to other Nodes.

So when an endpoint is hit, I’d like to embed objects one level deep, and link after that:

  • /user has user data and “_embedded” projects, but those projects only
    contain “_links” to nodes (and self)
  • /project/1234 has “_embedded” nodes, but those nodes “_links” to further data.

And so on.

The Jackson JSONFilters look close, but I’m not quite grasping it. Especially relevant is that sometimes a property will be mapped in a collection of “_embedded” and sometimes in “_links” using different techniques.

Any one ever try something like this?

There is HalBuilder, but it seems like it requires hand serialization, which I’d like to avoid. Then again, Jackson seems to be almost as much code as hand serializing.

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1 Answer

  1. Editorial Team

    You’ll need to implement your custom Jackson Serializer ( http://jackson.codehaus.org/1.7.9/javadoc/org/codehaus/jackson/map/JsonSerializer.html )

    Take a look at Spring Hateoas project. They have implemented a jackson extension HalJacksonModule ( https://github.com/SpringSource/spring-hateoas/commit/61e73107c1213556c025dc8f68a8784daf089796
    ) to enable HAL serialization to Jackson. I think you can use it or adapt it to your needs.

    Additionally, the project “Spring Data Rest” (http://www.springsource.org/spring-data/rest) provides a way to export your JPA model to REST (with hateoas) using Spring Hateoas. You may look at the code to get inspiration or simply use the framework in your code. (Remember to register the HalJacksonModule into the ObjectMapper).

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