<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-openfeign</artifactId>
        <version>3.1.3</version> <!-- 與Spring Boot版本匹配 -->
    </dependency>
</dependencies>

@SpringBootApplication
@EnableFeignClients // 關(guān)鍵注解
public class DemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;

@FeignClient(
    name = "thirdPartyApi", 
    url = "https://api.example.com" // 第三方接口基地址
)
public interface ThirdPartyClient {

    // 示例：GET請(qǐng)求
    @GetMapping("/users/{id}")
    UserResponse getUser(@PathVariable("id") Long userId);

    // 示例：POST請(qǐng)求
    @PostMapping("/orders")
    OrderResponse createOrder(@RequestBody OrderRequest request);
}

// 請(qǐng)求示例
public class OrderRequest {
    private String productId;
    private Integer quantity;
    // getters/setters
}

// 響應(yīng)示例
public class UserResponse {
    private Long id;
    private String name;
    private String email;
    // getters/setters
}

@Service
public class ApiService {

    @Autowired
    private ThirdPartyClient thirdPartyClient; // 注入Feign客戶(hù)端

    public UserResponse fetchUser(Long userId) {
        return thirdPartyClient.getUser(userId); // 調(diào)用第三方API
    }

    public void createNewOrder(OrderRequest request) {
        OrderResponse response = thirdPartyClient.createOrder(request);
        System.out.println("Order created: " + response.getOrderId());
    }
}

@FeignClient(name = "authApi", url = "https://api.example.com")
public interface AuthClient {

    @GetMapping("/profile")
    ProfileResponse getProfile(
        @RequestHeader("Authorization") String token // 動(dòng)態(tài)傳遞Header
    );
}

feign:
  client:
    config:
      default:
        connectTimeout: 5000  # 連接超時(shí)(ms)
        readTimeout: 10000     # 讀取超時(shí)(ms)

@Configuration
public class FeignConfig {
    @Bean
    Logger.Level feignLoggerLevel() {
        return Logger.Level.FULL; // 輸出完整請(qǐng)求日志
    }
}

logging:
  level:
    com.example.demo.client.ThirdPartyClient: DEBUG

public class CustomErrorDecoder implements ErrorDecoder {
    @Override
    public Exception decode(String methodKey, Response response) {
        if (response.status() == 404) {
            return new ResourceNotFoundException("API resource not found");
        }
        return new FeignException.BadRequest("API request failed");
    }
}

@Bean
public ErrorDecoder errorDecoder() {
    return new CustomErrorDecoder();
}

@RestController
public class DemoController {

    @Autowired
    private ApiService apiService;

    @GetMapping("/user/{id}")
    public UserResponse getUser(@PathVariable Long id) {
        return apiService.fetchUser(id);
    }
}