Uma visão geral de como construir APIs de forma produtiva utilizando os frameworks Spring Boot, Spring Data e Spring MVC integrados. Apresentação TDC São Paulo 2017, trilha de Java EE

1. Trilha Java EE
Emmanuel Neri
CONSTRUINDO APIS DE FORMA PRODUTIVA
COM SPRING BOOT, SPRING DATA E
SPRING MVC

2. EMMANUEL NERI
‣ Mestre em Desenvolvimento de Tecnologia
‣ Desenvolvedor desde 2010
‣ Atualmente desenvolvedor back-end na Navita
)(

3. PROBLEMA
Quais os obstáculos da construção de APIs?
Ambiente Objeto <—> JSON Acessos aos dados

4. AGENDA
Spring Boot
Spring MVC Spring Data

5. SPRING BOOT
Spring Boot
AUTO
CONFIGURAÇÃO
EMBEDDED
SERVLET
CONTAINERS
GERENCIAMENTO
DE DEPENDÊNCIAS

6. GERENCIAMENTO DE DEPENDÊNCIAS
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<version>1.5.3.RELEASE</version>
</dependency>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>1.5.3.RELEASE</version>
</plugin>
</plugins>
</build>

7. GERENCIAMENTO DE DEPENDÊNCIAS

8. AUTO CONFIGURAÇÃO
@SpringBootApplication
public class AppConfig {
public static void main(String[] args) {
SpringApplication.run(AppConfig.class, args);
}
}
@EnableAutoConfiguration
@AutoConfigureTestDatabase
@AutoConfigureMockMvc

9. AUTO CONFIGURAÇÃO
=========================
AUTO-CONFIGURATION REPORT
=========================
Positive matches:
-----------------
EmbeddedServletContainerAutoConfiguration matched:
...
DataSourceConfiguration.Tomcat matched:
...
Negative matches:
-----------------
ActiveMQAutoConfiguration:
Did not match:
RedisAutoConfiguration:
Did not match:
mvn spring-boot:run -Ddebug

10. AUTO CONFIGURAÇÃO
/src/main/resources/application.properties
spring.profiles.active=dev
server.port=8090
server.context-path=/api
spring.http.encoding.charset=UTF-8
spring.datasource.url=jdbc:postgresql://localhost:5432/db
spring.datasource.username=postgres
spring.datasource.password=postgres
spring.datasource.driver-class-name=org.postgresql.Driver
spring.jpa.show-sql=true

11. AUTO CONFIGURAÇÃO
spring.profiles.active=
spring.mail.host=
spring.sendgrid.api-key=
flyway.enabled=true # Enable flyway
liquibase.enabled=true
spring.data.cassandra.cluster-name=
spring.data.elasticsearch.cluster-name=
spring.data.mongodb.database=test
spring.data.redis.repositories.enabled=true
spring.activemq.broker-url=
….
https://docs.spring.io/spring-boot/docs/current/reference/html/common-application-properties.html

12. EMBEDDED SERVLET CONTAINERS
mvn spring-boot:run
s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>

13. SPRING MVC
Spring MVC
FACILIDADE NA
LEITURA DE
PARÂMETROS
ABSTRAÇÃO NA
SERIALIZAÇÃO /
DESERIALIZAÇÃO
SIMPLICIDADE NA
EXPOSIÇÃO DE APIS
CONSTRUÇÃO
SIMPLES
ESTRUTURA DE
RETORNO
TRATAMENTO DE
ERROS

14. SIMPLICIDADE NA EXPOSIÇÃO DE APIS
@RestController
@RequestMapping("/customers")
public class CustomerController {
@RequestMapping(method = RequestMethod.GET)
public List<Customer> findAll() {
return customerService.findAll();
}
}
http://localhost:8080/customers

15. ABSTRAÇÃO NA SERIALIZAÇÃO / DESERIALIZAÇÃO
@RequestMapping(method = RequestMethod.GET)
public List<Customer> findAll() {
return customerService.findAll();
}
@RequestMapping(method = RequestMethod.POST)
public void save(@RequestBody BillDTO billDTO) {
billService.save(billDTO);
}

16. ABSTRAÇÃO NA SERIALIZAÇÃO / DESERIALIZAÇÃO
import com.fasterxml.jackson.annotation.JsonFormat;
public final class BillDTO {
@JsonFormat(pattern = "yyyy-MM")
private YearMonth yearMonth;

17. FACILIDADE NA LEITURA DE PARÂMETROS
@RequestMapping(value = "/byUk/{customerId}/{identifier}/{yearMonth}",
method = RequestMethod.GET)
public Bill findByUk(@PathVariable("customerId") Long customerId,
@PathVariable("identifier") String identifier,
@PathVariable("yearMonth") YearMonth yearMonth) {
return billService.findByUk(customerId, identifier, yearMonth);
}
@RequestMapping(value = "/search", method = RequestMethod.GET)
public List<Customer> search(
@RequestParam(value = "id", required = false) Long id,
@RequestParam(value = "name", required = false) String name){
return customerService.search(new CustomerSearchTO(id, name));
}

18. CONSTRUÇÃO SIMPLES ESTRUTURA DE RETORNO
ResponseEntity.ok(bill);
ResponseEntity.badRequest().build();
@RequestMapping(method = RequestMethod.GET)
public ResponseEntity ok() {
return ResponseEntity.ok().build();
}
200
400
200
{
"id":1,
"customer":{
"name":"Customer"
},
"carrier":{
"name":"TIM"
},
"identifier":"23326",
“yearMonth”:"2017/06"
}
ResponseEntity.status(UNAUTHORIZED).build(); 401

19. TRATAMENTO DE ERROS
@ControllerAdvice
public class GlobalExceptionHandler {
@ExceptionHandler(BusinessException.class)
public ResponseEntity<Set<ExceptionTO>> handleError(BusinessException ex) {
return ResponseEntity.status(HttpStatus.BAD_REQUEST)
.body(Collections.singleton(new ExceptionTO(ex.getMessage())));
}
@ExceptionHandler(ConstraintViolationException.class)
public ResponseEntity<Set<ExceptionTO>> handleError(ConstraintViolationException
ex) {
final Set<ExceptionTO> erros = ex.getConstraintViolations().stream()
.map(c -> new ExceptionTO(c.getMessage()))
.collect(Collectors.toSet());
return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(erros);
}
@ExceptionHandler(Exception.class)
public ResponseEntity handleError(Exception ex) {
return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR)
.body("O sistema se encontra indisponível”);
}

20. SPRING DATA
Spring Data
SUPORTE A
DIFERENTE
FONTES DE
DADOS
ABSTRAÇÃO NO
ACESSO AOS
DADOS
IMPLEMENTAÇÕES
PADRÕES
CACHE

21. IMPLEMENTAÇÕES PADRÕES
public interface BillRepository extends JpaRepository<Bill, Long> {
‣ findAll()
‣ save(T object)
‣ save(Iterable<T> objects)
‣ flush()
‣ getOne(ID id)
‣ delete(ID id)
‣ deleteInBatch(Iterable<T> objects)

22. ABSTRAÇÃO NO ACESSO AOS DADOS
public Customer save(Customer customer) {
return customerRepository.save(customer);
}
public List<Customer> findAll() {
return customerRepository.findAll();
}
public Page<Customer> findPaginable(int page, int size) {
final Sort sort = new Sort(Sort.Direction.DESC, "name");
return customerRepository.findAll(
new PageRequest(page, size, sort));
}

23. ABSTRAÇÃO NO ACESSO AOS DADOS
Bill findByCustomerIdAndIdentifierAndYearMonth(Long customerId,
String identifier, YearMonth yearMonth);
@Modifying
@Query("delete from BillItem where bill.id = :#{#billId}")
void deleteByBillItem(@Param("billId") Long billId);
Hibernate: select bill… from bill bill0_ where bill0_.customer_id=? and
bill0_.identifier=? and bill0_.year_month=?
Hibernate: delete from bill where id=?

24. ABSTRAÇÃO NO ACESSO AOS DADOS
‣ Integração com QueryDSL
public interface BillRepository extends JpaRepository<Bill, Long>,
QueryDslPredicateExecutor<Bill> {
public Page<Bill> search(BillSearchTO searchTO) {
return billRepository.findAll(searchTO.toPredicate(),
new PageRequest(searchTO.getPage(), searchTO.getSize(),
new Sort(Sort.Direction.DESC, "id")));
}
public class BillSearchTO {
public BooleanBuilder toPredicate() {
final QBill qBill = QBill.bill;
final BooleanBuilder predicate = new BooleanBuilder();
if(!Strings.isNullOrEmpty(identifier)) {
predicate.and(qBill.identifier.eq(identifier));
}
if(initYearMonth != null) {
predicate.and(qBill.yearMonth.goe(initYearMonth));
}

25. ACESSO AOS DADOS
‣ Repositorios customizados
public interface BillRepositoryCustom {
Page<BillDTO> findAll(BillSearchTO searchTO);
}
public interface BillRepository extends JpaRepository<Bill, Long>,
QueryDslPredicateExecutor<Bill>, BillRepositoryCustom {
...
public class BillRepositoryImpl implements BillRepositoryCustom {
@PersistenceContext
private EntityManager entityManager;
@Override
public Page<BillDTO> findAll(BillSearchTO searchTO) {
final JPQLQuery jpaQuery = new JPAQuery(entityManager)
.from(qBill)
.join(qBill.carrier).fetchJoin()
.join(qBill.customer).fetchJoin()
.join(qBill.items).fetchJoin();
...

26. SUPORTE A DIFERENTE FONTES DE DADOS
‣ Módulos da Spring
‣ Módulos da comunidade
JPA LDAP
REST

27. SUPORTE A DIFERENTE FONTES DE DADOS
public interface BillFileRepository extends MongoRepository<BillFile, String> {
}
import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;
@Document(collection = "bill_file")
@Getter
public class BillFile {
@Id
private String id;
private String date;
private String content

28. CACHE
@SpringBootApplication
@EnableCaching
public class AppConfig {
@Cacheable("carriers")
public List<Carrier> findAll() {
return carrierRepository.findAll();
}
‣ JSR-107
‣ Caffeine
‣ Guava cache
‣ EhCache
‣ GemFire

29. FIM …
OBRIGADO!
https://github.com/emmanuelneri/productivity-with-spring
emmanuelnerisouza@gmail.com
https://github.com/emmanuelneri
@emmanuelnerii
www.emmanuelneri.com.br