CRUD Example Using Spring Boot JPA + H2 + Gradle

In this tutorial we will demo a Spring Boot CRUD application using REST + Spring Boot JPA + H2 + Gradle.

Create a spring boot project with below dependencies:

build.gradle:

dependencies {
	implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
	implementation 'org.springframework.boot:spring-boot-starter-web'
	compileOnly 'org.projectlombok:lombok'
	runtimeOnly 'com.h2database:h2'
	annotationProcessor 'org.projectlombok:lombok'
	testImplementation 'org.springframework.boot:spring-boot-starter-test'
}

application.properties:

spring.h2.console.enabled=true
spring.datasource.url=jdbc:h2:mem:testdb
spring.data.jpa.repositories.bootstrap-mode=default

Model class:

@Data
@NoArgsConstructor
@AllArgsConstructor
@Entity
public class Person {
	@Id
	@GeneratedValue
	private int id;
	private String name;
	private Integer age;
}

Repository:

@Repository
public interface MyRepository extends CrudRepository<Person,String>{
}

Service class:

@Service
public class MyService {
	@Autowired
    MyRepository myRepository;

	public Iterable<Person> getPersons() {
		return myRepository.findAll();
	}

	public Person addPerson(Person person) {
        return myRepository.save(person);
    }

	public Person updatePerson(Person person, String id) {
		Person person2 = myRepository.findById(id).get();
		person2.setName(person.getName());
		person2.setAge(person.getAge());

		return myRepository.save(person2);
	}

	public Person getPersonById(String id) {
		Person person = myRepository.findById(id).get();
		return person;
	}

	public void deletePerson(String id) {
		myRepository.deleteById(id);
	}
}

Controller class:

@RestController
@CrossOrigin(origins="http://localhost:4200/")
@RequestMapping("/api")
public class MyController {
	@Autowired
	MyService myService;

	@GetMapping("/getPersons")
	public Iterable<Person> getPersons() {
		return myService.getPersons();
	}
	
	@PostMapping("/addPerson")
    //@ResponseStatus(HttpStatus.CREATED)
    public Person addPerson(@RequestBody Person person){
        return myService.addPerson(person);
    }

	@PutMapping("/updatePerson/{id}")
	public Person updatePerson(@RequestBody Person person, @PathVariable String id){
		return myService.updatePerson(person,id);
	}

	@GetMapping("getPersonById/{id}")
	public Person getPersonById(@PathVariable String id){
		return myService.getPersonById(id);
	}

	@DeleteMapping("/deletePerson/{id}")
	public void deletePerson(@PathVariable String id) {
		myService.deletePerson(id);
	}
}

Now start the application.
Do a POST call to below url with the below request:

http://localhost:8080/api/addPerson

{
    "name": "Prasanna Kumar",
    "age": 46
}

Here is the screenshot for the same:

To see the DB console: http://localhost:8080/h2-console

Hit “Connect” without any password.
You will land up in the console. There you can see all the tables:

Similarly you can test other API endpoints for – GET, PUT and DELETE operations.

Source code of the above example is here: https://github.com/heapsteep/ReST

If you want to know how to create a Spring Boot ReST with MongoDB click here.