In Spring Boot, using JPA for database operations usually requires the following steps:
1. Add dependencies
Add the Spring Data JPA dependency in the pom.xml file:
```xml
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
```
2. Configure data source
Configure data source information in the application.properties or application.yml file:
```
spring.datasource.url=jdbc:mysql://localhost:3306/test?useSSL=false&serverTimezone=UTC&useUnicode=true&characterEncoding=utf8mb4
spring.datasource.username=root
spring.datasource.password=root
spring.jpa.hibernate.ddl-auto=update
```
3. Create entity class
Use JPA annotations to create entity classes and specify mapping relationships with database tables:
```java
@Entity
@Table(name = "user")
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
@Column(name = "username")
private String username;
@Column(name = "password")
private String password;
// getters and setters
}
```
4. Create Repository interface
Create the Repository interface and annotate it with JPA annotations:
```java
public interface UserRepository extends JpaRepository<User, Long> {
List<User> findByUsername(String username);
}
```
5. Create Service class
Create a Service class, inject into Repository and implement related business logic:
```java
@Service
public class UserService {
@Autowired
private UserRepository userRepository;
public List<User> findByUsername(String username) {
return userRepository.findByUsername(username);
}
}
```