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This version is still in development and is not considered stable yet. For the latest stable version, please use Spring Data JPA 3.4.1! |
Getting Started
An easy way to bootstrap setting up a working environment is to create a Spring-based project via start.spring.io or create a Spring project in Spring Tools.
Examples Repository
The GitHub spring-data-examples repository hosts several examples that you can download and play around with to get a feel for how the library works.
Hello World
Let’s start with a simple entity and its corresponding repository:
@Entity
class Person {
@Id @GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String name;
// getters and setters omitted for brevity
}
interface PersonRepository extends Repository<Person, Long> {
Person save(Person person);
Optional<Person> findById(long id);
}Create the main application to run, as the following example shows:
@SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
@Bean
CommandLineRunner runner(PersonRepository repository) {
return args -> {
Person person = new Person();
person.setName("John");
repository.save(person);
Person saved = repository.findById(person.getId()).orElseThrow(NoSuchElementException::new);
};
}
}Even in this simple example, there are a few notable things to point out:
-
Repository instances are automatically implemented. When used as parameters of
@Beanmethods, these will be autowired without further need for annotations. -
The basic repository extends
Repository. We suggest to consider how much API surface you want to expose towards your application. More complex repository interfaces areListCrudRepositoryorJpaRepository.
