The best way to write a custom Spring Data Repository

Introduction In this article, I’m going to show you the best way to write a custom Spring Data Repository. While the default JpaRepository methods, as well as the query methods, are very convenient in many situations, there might be times when you need custom Repository methods that can take advantage of any JPA provider-specific functionality.

JPA AttributeConverter – A Beginner’s Guide

Introduction In this article, we are going to see how the JPA AttributeConverter works and how we can use it to customize the entity attribute to the database column mapping. For instance, we could use a JPA AttributeConverter to map a Java MonthDay to a database DATE column because Hibernate doesn’t offer a built-in MonthDayType to handle this particular mapping.

The best way to use a Hibernate ResultTransformer

Introduction In this article, I’m going to present the best way to use a Hibernate ResultTransformer so that you can customize the result set of a given JPA or Hibernate query. As I already explained, the Hibernate ResultTransformer is a very powerful mechanism, allowing you to customize a JPQL, Criteria API, or native SQL query result set in any possible way.

MySQL 8 support for custom SQL CHECK constraints

Introduction In this article, we are going to test the MySQL 8 implementation of custom SQL CHECK constraints. Although the CHECK clause is a standard SQL feature, prior to MySQL 8.0.16, the clause was parsed and ignored, so this functionality could only be emulated via BEFORE INSERT and UPDATE triggers.

How to map a PostgreSQL HStore entity property with JPA and Hibernate

Introduction The Hypersistence Utils open-source project allows you to map a great variety of database types that are not supported natively by Hibernate ORM (e.g. JSON, ARRAY, YearMonth, Month, INET addresses). In this article, we are going to see how you can map a PostgreSQL HStore type, which allows you to store key/value pairs, to a Java Map entity property when using JPA and Hibernate.

How to map a PostgreSQL Enum ARRAY to a JPA entity property using Hibernate

Introduction The Hypersistence Utils OSS project allows you to map JSON, ARRAY, YearMonth, Month or database-specific columns (e.g., INET addresses). In this article, we are going to see how you can map a PostgreSQL Enum ARRAY type to a Java array entity property when using JPA and Hibernate.

How to bind custom Hibernate parameter types to JPA queries

Introduction In this article, we are going to see how we can bind a custom Hibernate parameter type to a JPA query. I decided to write this article after one of my hibernate-types framework users created this very interesting issue on GitHub.

How to map java.time Year and Month with JPA and Hibernate

Introduction In this article, we are going to see how you can map the java.time.Year and java.time.Month with both JPA and Hibernate. As explained in this article, JPA 2.2 supports LocalDate, LocalTime, LocalDateTime, OffsetTime, OffsetDateTime from the java.time package. Hibernate has been supporting the Java 8 Date/Time classes since 5.0 via the hibernate-java8 dependency, but since version 5.2, this dependency was merged with hibernate-core so you get the Duration, Instant and ZonedDateTime types in addition to the ones supported by JPA 2.2. However, neither JPA nor Hibernate supports the java.time.Year type out-of-the-box…. Read More

How to customize the Hypersistence Utils JSON Serializer

Introduction The Hypersistence Utils open-source project allows you to map JSON, ARRAY, and PostgreSQL ENUM types and provides a simple way of adding immutable Hibernate Types. After adding support for customizing the Jackson ObjectMapper, the next most-wanted issue was to provide a way to customize the JSON serializing mechanism. In this article, you are going to see how you can customize the JSON serializer used by the JSON Types.

The hibernate-types open-source project is born

Introduction Recently, I got a very interesting request from one of my readers. Since I’ve been providing many custom types to support JSON, ARRAY, or nullable Character types, I decided to start a new open-source project to make it easier for you to get these extra Hibernate Types.