定义api消费侧的接口，采用@FeignClient注解，会动态生成实现类。根据cloud-payment-service的名称去eureka上找应用。

@Service
@FeignClient(value="cloud-payment-service")
public interface PaymentFeignService {
    @GetMapping(value="/payment/get/{id}")
    public CommonResult<Payment> getPaymentById(@PathVariable("id") Long id);
    
    @GetMapping(value="/payment/feign/timeout")
    public String paymentFeignTimeout();
    
}

调用方通过使用该声明的接口，就可以调用相关api。

@RestController
@RequestMapping(value="/consumer")
public class OrderFeignController {
    @Autowired
    private PaymentFeignService paymentFeignService;

    @GetMapping(value="/payment/get/{id}")
    public CommonResult<Payment> getPaymentById(@PathVariable("id") Long id){
        return paymentFeignService.getPaymentById(id);
    }
    
    @GetMapping(value="/payment/feign/timeout")
    public String paymentFeignTimeout() {
        return paymentFeignService.paymentFeignTimeout();
    }
}

采用@EnableFeignClients注解，启用openfeign

@SpringBootApplication
@EnableFeignClients
public class CloudConsumerFeignOrder80 {
    public static void main(String[] args) {
        SpringApplication.run(CloudConsumerFeignOrder80.class, args);
    }
}

配置文件如下

# 端口号80可以不带端口
server:
  port: 80

# 声明应用名称
spring:
  application:
    name: cloud-consumer-order


# eureka注册中心地址，定义实例名称，选择ip的方式
eureka:
  client:
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka/
  instance:
    prefer-ip-address: true
    instance-id: ${spring.application.name}:${server.port}
    
# openfeign 定义连接超时时间，以及logger日志级别    
feign:
  client:
    config:
      default:
        connect-timeout: 5000
        read-timeout: 5000
        logger-level: basic
        
# 类的日志级别        
logging:
  level:
    com.example.springcloud.service.PaymentFeignService: debug