Spring @Repository Annotation Example

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In this quick article, we will discuss how to use the Spring or Spring Boot @Repository annotation with an example.

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Spring @Repository Overview  

DAO or Repository classes usually represent the database access layer in an application and should be annotated with @Repository annotation.

As of Spring 2.5, this annotation also serves as a specialization of @Component, allowing for implementation classes to be autodetected through classpath scanning.

 
@Repository annotation internally annotated with @Component annotation as shown in the below diagram:

Whenever we annotated a class with @Repository annotation then Spring Container will automatically create a Spring bean for that class.

@Repository Annotation Example

Let's create a simple Spring boot application to bootstrap quickly. Add the below dependencies to your pom.xml file.

<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency>

Create User JPA Entity

Let's create a simple User JPA entity that maps with the users table in the database:

@Entity @Table(name = "users") class User { @Id @GeneratedValue(strategy = GenerationType.AUTO) private int id; private String name; public User(int id, String name) { super(); this.id = id; this.name = name; } public User() {} public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } }

Create UserRepository

Next, create a UserRepository interface and annotate with @Repository annotation:

@Repository interface UserRepository extends JpaRepository < User, Integer > { }

Note Spring Data JPA automatically provides an implementation for the above interface.

Create UserService and UserServiceImpl

interface UserService { public void saveUser(User user); } @Service class UserServiceImpl implements UserService { @Autowired private UserRepository userRepository; @Override public void saveUser(User user) { userRepository.save(user); } }

Testing

Let's write a code to test UserRepository to save user objects into database table:

@SpringBootApplication public class DemoApplication { public static void main(String[] args) { ConfigurableApplicationContext applicationContext = SpringApplication.run(DemoApplication.class, args); UserService userService = (UserService) applicationContext.getBean("userServiceImpl"); userService.saveUser(new User(10, "Ramesh")); } }

Complete Code

Here is the complete code for your reference:

import jakarta.persistence.*; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.context.ConfigurableApplicationContext; import org.springframework.data.jpa.repository.JpaRepository; import org.springframework.stereotype.Repository; import org.springframework.stereotype.Service; @SpringBootApplication public class DemoApplication { public static void main(String[] args) { ConfigurableApplicationContext applicationContext = SpringApplication.run(DemoApplication.class, args); UserService userService = (UserService) applicationContext.getBean("userServiceImpl"); userService.saveUser(new User(10, "Ramesh")); } } @Entity @Table class User { @Id @GeneratedValue(strategy = GenerationType.AUTO) private int id; private String name; public User(int id, String name) { super(); this.id = id; this.name = name; } public User() {} public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } } @Repository interface UserRepository extends JpaRepository < User, Integer > { } interface UserService { public void saveUser(User user); } @Service class UserServiceImpl implements UserService { @Autowired private UserRepository userRepository; @Override public void saveUser(User user) { userRepository.save(user); } }

Note that we have created ApplicationContext and retrieved bean using the getBean() method:

ConfigurableApplicationContext applicationContext = SpringApplication.run(DemoApplication.class, args); UserService userService = (UserService) applicationContext.getBean("userServiceImpl"); userService.saveUser(new User(10, "Ramesh"));

Usage of @Repository annotation in Spring Data JPA Repository

@Repository interface UserRepository extends JpaRepository < User, Integer > { }

Related Spring and Spring Boot Annotations

• Spring Boot @Bean Annotation Example
• Spring @Qualifier Annotation Example
• Spring @Autowired Annotation with Example
• Spring @Bean Annotation with Example
• Spring @Configuration Annotation with Example
• Spring @PropertySource Annotation with Example
• Spring @Import Annotation with Example
• Spring @ImportResource Annotation Example
• Spring - @Lazy Annotation Example
• Spring - @Primary Annotation Example
• Spring @PostConstruct and @PreDestroy Example
• Spring @Repository Annotation
• Spring @Service Annotation 
• The Spring @Controller and @RestController Annotations
• Spring Boot @Component, @Controller, @Repository and @Service
• Spring @Scope annotation with Prototype Scope Example
• Spring @Scope annotation with Singleton Scope Example
• Spring Boot @PathVariable
• Spring Boot @ResponseBody
• Spring @RequestBody - Binding Method Parameters to Request Body
• Spring Boot @ResponseStatus Annotation
• Spring Boot - Creating Asynchronous Methods using @Async Annotation
• @SpringBootTest Spring Boot Example
• @SpringBootTest vs @WebMvcTest
• @DataJpaTest Spring Boot Example
• Spring @PostConstruct and @PreDestroy Example
• Spring @GetMapping, @PostMapping, @PutMapping, @DeleteMapping and @PatchMapping
• Spring Boot @EnableAutoConfiguration Annotation with Example
• Spring Boot @SpringBootApplication Annotation with Example

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