Spring Boot JPA Stored Procedure Example - Call SQL Procedures with Ease

• Employee: Represents the entity that maps to the result of the stored procedure.
• EmployeeRepository: Defines a method to call the stored procedure using the @Procedure annotation.
• EmployeeService: Calls the repository method to fetch employee details.
• EmployeeController: Exposes a REST API to fetch employee details based on the employeeId parameter.

The annotations @Procedure and @NamedStoredProcedureQuery are used to map the method to the stored procedure in the database. The service and controller layer interact to expose this functionality through a REST API.

In Spring Boot, you can call a stored procedure using Spring Data JPA by defining a method in a repository interface and annotating it with @Procedure. Below is an example to demonstrate how to call a stored procedure using Spring Boot with JPA.

1. Create the Stored Procedure

Assume you have a stored procedure in your database like this:

CREATE PROCEDURE GetEmployeeDetails(IN employeeId INT)
BEGIN
    SELECT * FROM employees WHERE id = employeeId;
END;

2. Define an Entity Class

You need to create an entity class that maps to the result of the stored procedure. Here's an example:

@Entity
public class Employee {

    @Id
    private Integer id;

    private String name;
    private String position;
    
    // Getters and Setters
}

3. Create a Repository Interface

In the repository, you can define a method to call the stored procedure. You will use the @Procedure annotation to call the procedure.

public interface EmployeeRepository extends JpaRepository<Employee, Integer> {

    @Procedure(name = "GetEmployeeDetails")
    List<Employee> getEmployeeDetails(@Param("employeeId") Integer employeeId);
}

4. Configure the Stored Procedure in the Entity

You need to specify the name of the stored procedure in the entity or repository. You can use @Procedure to specify the procedure name.

@Entity
@NamedStoredProcedureQuery(
    name = "GetEmployeeDetails",
    procedureName = "GetEmployeeDetails",
    parameters = {
        @StoredProcedureParameter(mode = ParameterMode.IN, name = "employeeId", type = Integer.class)
    },
    resultClasses = Employee.class
)
public class Employee {
    // Same entity code as before
}

5. Call the Stored Procedure in a Service

In your service class, you can call the repository method to execute the stored procedure.

@Service
public class EmployeeService {

    @Autowired
    private EmployeeRepository employeeRepository;

    public List<Employee> getEmployeeDetails(Integer employeeId) {
        return employeeRepository.getEmployeeDetails(employeeId);
    }
}

6. Use the Service in a Controller

Finally, you can expose this functionality via a REST API.

@RestController
@RequestMapping("/employees")
public class EmployeeController {

    @Autowired
    private EmployeeService employeeService;

    @GetMapping("/details")
    public List<Employee> getEmployeeDetails(@RequestParam Integer employeeId) {
        return employeeService.getEmployeeDetails(employeeId);
    }
}

7. Application Properties

Ensure that you have the correct database configuration in your application.properties or application.yml.

spring.datasource.url=jdbc:mysql://localhost:3306/your_database
spring.datasource.username=root
spring.datasource.password=password
spring.jpa.hibernate.ddl-auto=update

Summary

This example demonstrates how to define and call a stored procedure in Spring Boot using JPA. The key points are:

• Use @Procedure to map a stored procedure.
• Use @NamedStoredProcedureQuery to specify the procedure details in the entity class.
• Define the parameters and return types accordingly.

This approach can be easily adapted for different types of stored procedures.