DevConfig*****************************************
@Configuration
public class DevConfig {

	@Autowired
	private DbService dbService;

	@Value("${spring.jpa.hibernate.ddl-auto}")
	private String strategy;

	@Bean
	public boolean inicializaBancoDeDados() throws ParseException {
		if (!"create".equals(strategy)) {
			return false;
		}
		dbService.inicializaBancoDeDados();
		return true;
	}

}

DbService****************************************
@Service
public class DbService {

	@Autowired
	private CategoriaRepository categoriaRepository;

	@Autowired
	private EstadoRepository estadoRepository;

	public void inicializaBancoDeDados() throws ParseException {

		Categoria cat1 = new Categoria(null, "Informática");
		Categoria cat2 = new Categoria(null, "Escritório");
		Categoria cat3 = new Categoria(null, "Cama mesa e banho");
		Categoria cat4 = new Categoria(null, "Eletrônicos");
		Categoria cat5 = new Categoria(null, "Jardinagem");
		Categoria cat6 = new Categoria(null, "Decoração");
		Categoria cat7 = new Categoria(null, "Perfumaria");
		categoriaRepository.saveAll(Arrays.asList(cat1, cat2, cat3, cat4, cat5, cat6, cat7));

	}

}


CATEGORIA RESOURCE***********************

@RestController
@RequestMapping(value="/categorias")
public class CategoriaResource {

	@Autowired
	private CategoriaService service;

	//BUSCAR POR ID
	@RequestMapping(value="/{id}",method=RequestMethod.GET)
	public ResponseEntity<Categoria> find(@PathVariable Integer id){
		Categoria obj = service.find(id);
		return ResponseEntity.ok().body(obj);
	}

	//INSERIR
	@RequestMapping(method=RequestMethod.POST)
	public ResponseEntity<Void>insert(@RequestBody Categoria obj){
		obj = service.insert(obj);
		URI uri = ServletUriComponentsBuilder.fromCurrentRequest().
				path("/{id}").buildAndExpand(obj.getId()).toUri();
		return ResponseEntity.created(uri).build();
	}

	//ATUALIZAR
	@RequestMapping(value="/{id}", method=RequestMethod.PUT)
	public ResponseEntity<Void> update(@RequestBody Categoria obj, @PathVariable Integer id){
		obj.setId(id);
		obj = service.update(obj);
		return ResponseEntity.noContent().build();
	}


	//EXCLUIR
	@RequestMapping(value="/{id}", method=RequestMethod.DELETE)
	public ResponseEntity<Void> delete(@PathVariable Integer id) {
		service.delete(id);
		return ResponseEntity.noContent().build();
	}

	//LISTAR TODAS
	@RequestMapping(method=RequestMethod.GET)
	public ResponseEntity<List<CategoriaDTO>> findAll() {
		List<Categoria> lista = service.findAll();
		//ou for para percorrer a lista
		List<CategoriaDTO> listaDTO = lista.stream().map(obj -> new CategoriaDTO(obj)).collect(Collectors.toList());
		return ResponseEntity.ok().body(listaDTO);
	}

}

CATEGORIA SERVICE********************
@Service
public class CategoriaService {

	@Autowired
	private CategoriaRepository rep;

	//BUSCAR POR ID
	public Categoria find (Integer id) {
		Optional<Categoria> obj = rep.findById(id);
		return obj.orElse(null);
	}

	//INSERIR
	public Categoria insert (Categoria obj) {
		obj.setId(null);
		return rep.save(obj);
	}

	//ATUALIZAR
	public Categoria update (Categoria obj) {
		find(obj.getId());
		return rep.save(obj);
	}

	//DELETAR
	public void delete (Integer id) {
		find(id);
		rep.deleteById(id);
	}

	//LISTAR TODAS
	public List<Categoria> findAll(){
		return rep.findAll();
	}


POM.XML*****************************

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

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-devtools</artifactId>
</dependency>

application.properties**********************************

spring.datasource.url=jdbc:mysql://localhost:3306/pweb_quarta?useTimezone=true&serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=root
spring.jpa.hibernate.ddl-auto=create
spring.jpa.show-sql=true
spring.jpa.properties.hibernate.format_sql=true