Giriş
Şu satırı dahil ederiz
import org.springframework.cloud.netflix.feign.FeignClient;
configuration Alanı
Örnek - Basic Authentication
import feign.auth.BasicAuthRequestInterceptor;
public class ZephyrFeignClientConfiguration {
@Value("${zephyr.api.username}")
private String jiraApiUsername;
@Value("${zephyr.api.password}")
private String jiraApiPassword;
@Bean
public BasicAuthRequestInterceptor basicAuthRequestInterceptor() {
return new BasicAuthRequestInterceptor(jiraApiUsername, jiraApiPassword);
}
}
@FeignClient(name = "...", url = "...",
configuration = ZephyrFeignClientConfiguration.class)
public interface ZephyrFeignClient {
@RequestMapping(value = "/execution", method = RequestMethod.GET)
ExecutionListResponseDto getListOfExecutions(@RequestParam(name = "issueId")
String issueId);
}
Notice — do not mark the whole class as @Configuration. This would make the BasicAuthRequestInterceptor bean available in the whole Spring context and therefore it would be picked up by other Feign Clients.
Örnek - Token Authentication
import feign.RequestInterceptor;
import feign.RequestTemplate;
public class SlackFeignClientConfiguration {
@Value("${slack.app.oauth.accessToken}")
private String slackOauthAccessToken;
@Bean
public RequestInterceptor bearerTokenRequestInterceptor() {
return new RequestInterceptor() {
@Override
public void apply(RequestTemplate template) {
template.header("Authorization",
String.format("Bearer %s", slackOauthAccessToken));
}
};
}
}
@FeignClient(name = "Slack", url = "...",
configuration = SlackFeignClientConfiguration.class)
public interface SlackFeignClient {
@RequestMapping(
value = "/chat.postMessage",
method = RequestMethod.POST,
consumes = "application/json",
produces = "application/json")
SlackMessageResponseDto postSlackMessage(@RequestBody(required = true)
SlackMessageRequestDto messageRequest);
}fallback Alanı
Bu alanın çalışması için application.properties dosyasına şu
eklenir. Böylece servis çalışmıyorsa fallback metodu çağrılır
feign.circuitbreaker.enabled=true
Örnek
@FeignClient(name="score-segment", fallback = ScoreSegmentFallback.class)
public interface ScoreSegmentProxy {
@GetMapping("/score-segment/{idNumber}")
public ScoreSegmentResponse retrieveExchangeValue(@PathVariable BigInteger idNumber);
}
@Component
public class ScoreSegmentFallback implements ScoreSegmentProxy {
@Override
public ScoreSegmentResponse retrieveExchangeValue(BigInteger idNumber) {
return new ScoreSegmentResponse(BigInteger.ONE);
}
}name Alanı
url belirtilmediği için Eureka sunucusundan servisi bulur
Örnek
import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import com.example.EmployeeDashBoardService.domain.model.EmployeeInfo;
@FeignClient(name="EmployeeSearch" )//Service Id of EmployeeSerach service
public interface EmployeeServiceProxy {
@RequestMapping("/employee/find/{id}")
public EmployeeInfo findById(@PathVariable(value="id") Long id);
@RequestMapping("/employee/findall")
public Collection<EmployeeInfo> findAll();
}
Feign dynamically generates the implementation of the interface we created, so Feign has to know which service to call beforehand. That's why we need to give a name for the interface, which is the {Service-Id} of EmployeeService. Now, Feign contacts the Eureka server with this Service Id, resolves the actual IP/hostname of the EmployeeService, and calls the URL provided in Request Mapping.
url Alanı
Eğer Eureka kullanmıyorsak, URL ile adresi belirtmek gerekir.
Örnek - application.properties
application.properties şöyle
olsunzephyr:
api:
baseUrl: https://jira.my-company.com/jira/rest/zapi/latest@FeignClient(name = "Zephyr", url = "${zephyr.api.baseUrl}",
configuration = ZephyrFeignClientConfiguration.class)
public interface ZephyrFeignClient {
@RequestMapping(value = "/execution", method = RequestMethod.GET)
ExecutionListResponseDto getListOfExecutions(@RequestParam(name = "issueId")
String issueId);
}
Örnek - dynamic URL
Şöyle yaparız
import java.net.URI;
@FeignClient(name = "exchangeratelistfeignservice",url = "https://dummy.com")
public interface ExchangeRateListFeignService {
@GetMapping("")
ResponseEntity<String> getAllExchangeRates(URI baseUrl);
}
@GetMapping Örnekleri
Örnek
@FeignClient(name = "jsonplaceholder", url = "https://...")
public interface PostClient {
@GetMapping
List<PostDTO> getPosts();
}Örnek
@FeignClient(url = "<host:port for serviceB>", name = "serviceB")
public interface ServiceBClient{
@GetMapping("/hello")
public ResponseEntity<String> sayHello();
}Örnek - @PathVariable İle Parametre
@FeignClient(name = "products", url = "https://dummyjson.com/products")
public interface ProductClient {
@GetMapping("/{id}")
Product fetchProduct(@PathVariable int id);
}@RequestMapping Örnekleri
Örnek - @RequestMapping ile Get
@FeignClient(name = “external-service”, url = “${external-service.url}”,
configuration = ServiceConfiguration.class)
public interface ExternalServiceClient {
@RequestMapping(method = RequestMethod.GET, value = “/external- data/{time}”,
consumes = “application/json”)
Data load(@PathVariable(“time”) Long time);
}
Örnek
@FeignClient(name = "bonus", url = "http://localhost:8081/bonus")
public interface BonusClient {
@RequestMapping(value = "/register", method = RequestMethod.POST)
String register();
}
@FeignClient(name = "notification", url = "http://localhost:8082/notification")
public interface NotificationClient {
@PostMapping("/send")
String send(@RequestBody NotificationRequest notificationRequest);
}
@RestController
@RequestMapping("/bonus")
public class BonusController {
@PostMapping("/register")
String register() {
...
}
}
@RestController
@RequestMapping("/notification")
public class NotificationController {
@PostMapping("/send")
String send(@RequestBody NotificationRequest notificationRequest) {
...
}
}Örnek - RequestMapping + BasicAuthRequestInterceptor
BasicAuthentication kullanarak Get isteği göndermek için şöyle
yaparız. Burada Spring MVC'ye aiıt
@DeleteMapping
@GetMapping
@PostMapping
@PutMapping
kullanılabilir.
Parametre geçmek için
@PathVariable
@RequestHeader
@RequestParam
kullanılabilir.
import org.springframework.cloud.openfeign.FeignClient;
@FeignClient(name = "Zephyr", url = "${zephyr.api.baseUrl}",
configuration = ZephyrFeignClientConfiguration.class)
public interface ZephyrFeignClient {
@RequestMapping(value = "/execution",method = RequestMethod.GET)
Foo getListOfExecutions(@RequestParam(name = "issueId") String issueId);
}
Burada url değeri application.yml dosyasında şöyle
tanımlızephyr:
api:
baseUrl: https://jira.my-company.com/jira/rest/zapi/latest
import feign.auth.BasicAuthRequestInterceptor;
public class ZephyrFeignClientConfiguration {
@Value("${zephyr.api.username}")
private String jiraApiUsername;
@Value("${zephyr.api.password}")
private String jiraApiPassword;
@Bean
public BasicAuthRequestInterceptor basicAuthRequestInterceptor() {
return new BasicAuthRequestInterceptor(jiraApiUsername, jiraApiPassword);
}
}
Kullanmak için şöyle
yaparız@Service
@RequiredArgsConstructor
public class MyService {
private final ZephyrFeignClient zephyrClient;
public void fetchData() {
Foo foo = zephyrClient.getListOfExecutions("5112096");
...
}
}
