hibernate-pg-json

Provide json/jsonb mapping for hibernate

Configuration

1) Import dependency in maven

    <dependency>
      <groupId>com.datapublica.pg</groupId>
      <artifactId>hibernate-json</artifactId>
      <version>${hibernate-pg-json.version}</version>
    </dependency>

NB: This has not direct dependency to avoid version clashes.

2) Configure the dialect Use com.datapublica.pg.dialect.PostgreSQLJsonDialect as the DatabasePlatform.

If you have Hibernate 5, you can use PostgreSQL94JsonDialect which includes 9.4 new make_* functions.

3) Import types Add com.datapublica.pg.types to your entity packages to scan.

4) [Test] To use H2 in tests Configure the dialect com.datapublica.pg.dialect.H2JsonDialect

Example

@Type(type = "JsonSet", parameters = {
        @Parameter(name = "type", value = "String")
})
private Set<String> tags;

This will map the field tags to a jsonb column which is a list of strings (structured as Set in your domain).

If you want to map to a simple json column, do the following.

@Type(type = "JsonSet", parameters = {
        @Parameter(name = "type", value = "String"),
        @Parameter(name = "binary", value = "false")
})
private Set<String> tags;

Generic Types

As stated previously, all types support the parameter binary which is by default true which selects jsonb over json.

Classes references are any class name available via Class.forName. A default prefix may be given to enhance readability.

Json

Map a complex object directly.

Object class is given via parameter type (default prefix java.lang.).

JsonList

Map a list of objects.

List content class is given via parameter type (default prefix java.lang.).

JsonSet

Map a set of objects.

Set content class is given via parameter type (default prefix java.lang.).

JsonMap

Map a map object.

Key class is given via parameter key (default prefix java.lang.).

Value class is given via parameter value (default prefix java.lang.).

JsonCollection

Map a generic collection.

Collection content class is given via parameter type (default prefix java.lang.).

Container class name must be given via parameter container (default prefix java.util.)

Specific type

If you want to define a complex type composition like Map<String, List<Integer>> you have to create a new type.

public class MyComplexType extends JsonType {
    public MyComplexType() {
        TypeFactory tf = MAPPER.getTypeFactory();
        CollectionType listIntegerType = tf.constructCollectionType(List.class, Integer.class);
        // First parameter is the jackson type, second is the binary parameter.
        init(tf.constructMapType(HashMap.class, SimpleType.construct(String.class), listIntegerType), true);
    }
}

After that you can use @Type(type = "a.b.c.MyComplexType").

You can either use the JsonType(JavaType, boolean) constructor or the method to have a later initialization (to create parametrized types)

Mapper customization

The jackson Object Mapper is (currently) defined as static final in com.datapublica.pg.types.JsonType (field MAPPER). If you want more customization on this (say for date serialization for instant), feel free to add options.

Raw Types

If you want to store a blob of json without mappers you can use the types RawJson and RawJsonb. The field will need to be in String type.

@Type(type = "RawJsonb")
private String payload;

In this example, payload will be stored as a jsonb column and can be queried as such.

Debug helper

• Unknown SQL type code 1999 or 2000

You forgot to include the dialect (database-platform) in your configuration.

• Unknown type Json

You forgot to import types (packages to scan) in your configuration.

• Class not found PostgreSQL94Dialect

You are using Hibernate 4.x and therefore cannot use PostgreSQL94JsonDialect in your code, just use PostgreSQLJsonDialect.