Object mapper is the principal actor elegance of Jackson library. Object mapper magnificence object mapper gives functionality for analyzing and writing JSON, either to and from fundamental POJOs (simple antique java items) or to and from a trendy-cause JSON tree model (JsonNode), as well as related functionality for acting conversions. It is also fairly customizable to paintings both with distinctive sorts of JSON content material and to help more superior item standards inclusive of polymorphism and object identity. Object mapper also acts as a factory for extra superior object reader and object writer lessons.

The easiest way to achieve this goal is to set the hibernate.types.Jackson.object.mapper configuration property in the hibernate.properties file:

hibernate.types.jackson.object.mapper=com.vladmihalcea.hibernate.type.json.loader.CustomObjectMapperSupplier

What’s high-quality about customizing the hibernate-types project is that you may use both the hibernate-precise hibernate.Properties or you could provide a hibernate-types.properties report in case you can not alter hibernate.properties.

You can even supply a different Java properties file via the hibernate-types.properties.path System property.

The CustomObjectMapperSupplier can look as follows:

        ObjectMapper objectMapper = new ObjectMapper().findAndRegisterModules();

        SimpleModule simpleModule = new SimpleModule(

            new Version(1, 0, 0, null, null, null)

        simpleModule.addSerializer(new MoneySerializer());

        objectMapper.registerModule(simpleModule);

Here, we are the usage of a custom ObjectMapper that uses our MoneySerializer for managing BigDecimal java item types:

                JsonGenerator jsonGenerator,

                SerializerProvider provider)

            value.setScale(2, BigDecimal.ROUND_HALF_UP).toString()

    public Class<BigDecimal> handledType() {

So, if you are persisting the following Book entity which has a JSON properties attribute:

        "   \"title\": \"High-Performance Java Persistence\"," +

        "   \"author\": \"Vlad Mihalcea\"," +

        "   \"publisher\": \"Amazon\"," +

When fetching the Book entity, we can see that the BigDecimal takes only two decimals:

    book.getProperties().get("price").asText()

For even more flexibility, you can use the programmatic configuration.

Assuming we have the following Object type that we want to serialize as JSON:

    //Getters and setters omitted for brevity

And, we have an Event entity that maps the Location Java Object to a JSON PostgreSQL column type:

In this blog, we will discuss How to customize the Jackson ObjectMapper used by Hibernate-Types

How to customize the Jackson Object Mapper used by Hibernate-Types

Considering we have a Book entity that defines a properties attribute that is associated with a JSON column in the database.

The Book entity can be mapped as follows:

Persisting and fetching the Book entity:-

Now, let’s assume we have added the following Book entity in our database:

        "   "title": "High-Performance Java Persistence"," +

        "   "author": "Vlad Mihalcea"," +

When persisting the Book entity, Hibernate will issue the proper SQL INSERT statement:

        "title":"High-Performance Java Persistence",

Now, we fetching the Book entity by its natural identifier, we can see that the properties JSON attribute is fetched as a JsonNode:

    book.getProperties().get("title").asText()

Now, if we want to fetch the properties entity attribute using JPQL, we can execute the following query:

    "where b.isbn = :isbn", JsonNode.class)

And everything works properly since the JPQL query is parsed and the underlying Hibernate Type that handles the properties attribute is going to be known when building the result.

Fetching the JSON attribute using native SQL:-

However, if we try to do the same using a native SQL query:

JsonNode properties = (JsonNode) entityManager

Hibernate will throw the following MappingException:

javax.persistence.PersistenceException: org.hibernate.MappingException: No Dialect mapping for JDBC type: 1111

The 1111 JDBC type corresponds to Types.OTHER is what the PostgreSQL JDBC Driver uses for JSON column types.

Mapping Types.OTHER to JsonNodeBinaryType:-

object mapper

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Trending Blogposts on object mapper

How to customize the Jackson Object Mapper used by Hibernate-Types

How to fix the Hibernate “No Dialect mapping for JDBC type” issue

Popular Discussions on object mapper