Supporting PostgreSQL JSON types in jOOQ using Jackson. Adapted from the GSON example found at https://www.jooq.org/doc/3.9/manual/code-generation/custom-data-type-bindings/

jooq-db-config.xml

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<configuration xmlns="http://www.jooq.org/xsd/jooq-codegen-3.9.0.xsd">
    <jdbc>
        <driver>org.postgresql.Driver</driver>
        <url>jdbc:postgresql://localhost:5432/foo</url>
        <user>foo</user>
        <password>bar</password>
    </jdbc>
    <generator>
        <name>org.jooq.util.JavaGenerator</name>
        <database>
            <name>org.jooq.util.postgres.PostgresDatabase</name>
            <includes>.*</includes>
            <excludes/>
            <inputSchema>public</inputSchema>
            <outputSchemaToDefault>true</outputSchemaToDefault>
            <forcedTypes>
                <forcedType>
                    <userType>com.fasterxml.jackson.databind.JsonNode</userType>
                    <binding>com.pledgepot.data.access.db.jooq.JsonBinder</binding>
                    <expression>.*JSON.*</expression>
                    <types>.*</types>
                </forcedType>
            </forcedTypes>
        </database>
        <target>
            <packageName>com.example.jooq.generated</packageName>
            <directory>modules/db-access//src/main/java</directory>
        </target>
    </generator>
</configuration>

JsonBinder.java

package be.objectify.example.jooq;

import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;
import java.sql.Types;
import java.util.Objects;
import com.fasterxml.jackson.databind.JsonNode;
import org.jooq.Binding;
import org.jooq.BindingGetResultSetContext;
import org.jooq.BindingGetSQLInputContext;
import org.jooq.BindingGetStatementContext;
import org.jooq.BindingRegisterContext;
import org.jooq.BindingSQLContext;
import org.jooq.BindingSetSQLOutputContext;
import org.jooq.BindingSetStatementContext;
import org.jooq.Converter;
import org.jooq.impl.DSL;
import play.libs.Json;

/**
 * @author Steve Chaloner (steve@objectify.be)
 */
public class JsonBinder implements Binding<Object, JsonNode> {

    @Override
    public Converter<Object, JsonNode> converter() {
        return new Converter<Object, JsonNode>() {
            @Override
            public JsonNode from(Object t) {
                return t == null ? Json.newObject() : Json.parse("" + t);
            }

            @Override
            public Object to(JsonNode u) {
                return u == null ? null : Json.stringify(u);
            }

            @Override
            public Class<Object> fromType() {
                return Object.class;
            }

            @Override
            public Class<JsonNode> toType() {
                return JsonNode.class;
            }
        };
    }

    @Override
    public void sql(final BindingSQLContext<JsonNode> ctx) throws SQLException {
        ctx.render().visit(DSL.val(ctx.convert(converter()).value())).sql("::json");
    }

    @Override
    public void register(final BindingRegisterContext<JsonNode> ctx) throws SQLException {
        ctx.statement()
           .registerOutParameter(ctx.index(),
                                 Types.VARCHAR);
    }

    @Override
    public void set(final BindingSetStatementContext<JsonNode> ctx) throws SQLException {
        ctx.statement()
           .setString(ctx.index(),
                      Objects.toString(ctx.convert(converter()).value(),
                                       null));
    }

    @Override
    public void set(final BindingSetSQLOutputContext<JsonNode> ctx) throws SQLException {
        throw new SQLFeatureNotSupportedException();
    }

    @Override
    public void get(final BindingGetResultSetContext<JsonNode> ctx) throws SQLException {
        ctx.convert(converter()).value(ctx.resultSet().getString(ctx.index()));
    }

    @Override
    public void get(final BindingGetStatementContext<JsonNode> ctx) throws SQLException {
        ctx.convert(converter()).value(ctx.statement().getString(ctx.index()));
    }

    @Override
    public void get(final BindingGetSQLInputContext<JsonNode> ctx) throws SQLException {
        throw new SQLFeatureNotSupportedException();
    }
}