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Table of contents
1.
Introduction
2.
What is Spring Data JPA?
3.
Features of Spring Data JPA 
4.
Reasons to use Spring Data JPA
4.1.
No-code Repository
4.2.
Reduced boilerplate code
4.3.
Generated queries
5.
Spring Data Repository
6.
Spring Boot Starter Data JPA
7.
FAQs
8.
Key Takeaways 
Last Updated: Mar 27, 2024

Spring Data JPA

Author Juhi Sinha
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Introduction

When developing a new application, we should concentrate on the business logic instead of technical complexity and boilerplate code. That's why the Java Persistent API (JPA) and Spring Data JPA specifications are so popular.

This article will learn about Spring Data JPA. So, without any further ado, let's get started!

What is Spring Data JPA?

Spring Data JPA is a member of the Spring Data family of frameworks. Spring Data makes it easier to create Spring-driven applications that use non-relational databases, map-reduction frameworks, cloud services, and advanced relational database support, as well as traditional relational database support.

Most of the JDBC-based database access and ORM is handled by Spring Data JPA (Object Relational Mapping). It reduces the boilerplate code that JPA requires. It simplifies and accelerates the implementation of our persistence layer. Spring Data JPA aims to simplify data access layer implementation by limiting the effort required.

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Features of Spring Data JPA 

The features of Spring Data JPA are as follows:

  • Support for constructing repositories using Spring and JPA.
  • Querydsl predicates are supported, resulting in type-safe JPA queries.
  • Auditing of domain classes in a transparent manner.
  • Support for pagination, dynamic query execution, and incorporating custom data access code.
  • At the bootstrap time, @Query annotated queries are validated.
  • Entity mapping based on XML is supported.
  • By introducing @EnableJpaRepositories, JavaConfig-based repository configuration is now possible.

Reasons to use Spring Data JPA

Our job becomes easier with Spring Data. They can integrate JPA into the Spring stack due to the additional layer on top of JPA. They also provide functionality that we would otherwise have to implement.

Spring Data JPA is useful for a variety of reasons that are as follows:

No-code Repository

The repository pattern is popular persistence-related patterns. It hides the data store's implementation details, allowing us to write business code at a higher abstraction level.

The pattern isn't difficult to implement, but writing the standard CRUD operations for each entity generates repetitive code. We can extend a set of repository interfaces provided by Spring Data JPA to define a specific repository for one of our entities.

Reduced boilerplate code

Spring Data JPA makes things even easier by including a default implementation for each method defined by one of its repository interfaces. That means we don't have to worry about implementing basic read and write operations. Even though none of these operations require much code, not having to implement them makes life easier and reduces the risk of stupid bugs.

Generated queries

Another useful feature of Spring Data JPA is the ability to generate database queries based on method names. As long as our query isn't too complicated, we have to create a method on our repository interface that begins with find...By. The method name is then parsed, and a query is created for it by Spring.

Spring Data Repository

The three repositories provided by Spring Data JPA are as follows:

Spring Data Repository Description
CrudRepository It includes standard functions such as create, delete, read, and update. It has methods such as delete(), findOne(), findAll(), save(), and so on.
PagingAndSortingRepository It adds the findAll methods to the CrudRepository and extends it. It enables us to paginate the sorting and retrieval of data.
JpaRepository It's a JPA repository. Spring Data JPA is where it's defined. It extends both the CrudRepository and the PagingAndSortingRepository repositories. It includes JPA-specific methods such as flush(), which is used for flushing the persistence context.

 

Spring Boot Starter Data JPA

Spring Boot includes the spring-boot-starter-data-jpa dependency for efficiently connecting Spring applications to relational databases. The spring-boot-starter-data-jpa uses the dependency of spring-boot-jpa. Now let us see the code:

 

<dependency>  
<groupId>org.springframework.boot</groupId>  
<artifactId>spring-boot-starter-data-jpa</artifactId>  
<version>2.2.2.RELEASE</version>  
</dependency> 

 

Tables/relations are used to construct databases. Previously, writing SQL queries was the method of choice. The data from objects will be stored in the table and vice versa using JPA.

On the other hand, JPA emerged from a different way of thinking. Before JPA, these frameworks were known as ORM.

JPA allows us to map application classes to database tables:

  • Entity Manager: Once we've defined the mapping, it'll take care of all database interactions.
  • JPQL (Java Persistence Query Language): It allows us to write queries that will run searches against entities. It's not the same as SQL queries. JPQL queries already understand the mapping between entities. If necessary, we can add more conditions.
  • Criteria API: It defines a Java-based API for performing database searches.

Read More. spring mvc vs spring boot

FAQs

  1. What is Spring Data JPA?
    Spring Data JPA is a member of the Spring Data family of frameworks. Spring Data makes it easier to create Spring-driven applications that use non-relational databases, map-reduction frameworks, cloud services, and advanced relational database support, as well as traditional relational database support.
     
  2. What is JPA?
    Spring Boot JPA (Java Persistence API) is a Java standard for managing relational data in Java programs. It enables data to be accessed and stored between Java objects/classes and relational databases.
     
  3. What are the features of Spring Data JPA?
    The features of Spring Data JPA are as follows:
  • Support for constructing repositories using Spring and JPA.
  • Querydsl predicates are supported, resulting in type-safe JPA queries.
  • Auditing of domain classes in a transparent manner.
  • Support for pagination, dynamic query execution, and incorporating custom data access code.
  • At the bootstrap time, @Query annotated queries are validated.
  • Entity mapping based on XML is supported.
  • By introducing @EnableJpaRepositories, JavaConfig-based repository configuration is now possible.

 

Key Takeaways 

This article has learned about Spring Data JPA features, Repository, and why to use Spring Data JPA. 

You can read our previous blogs on Spring Boot JPA. If you are eager to learn advanced front-end web development, Coding Ninjas is here with one of the best courses available, which you can find here

 

Thank you for reading!

 

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