Feign是一个声明式的http客户端，官方地址：https://github.com/OpenFeign/feign
1.引入依赖
org.springframework.cloud
spring-cloud-starter-openfeign
2.在order-service的启动类添加@EnableFeignClients注解开启Feign的功能：
@MapperScan("cn.itcast.order.mapper")
@SpringBootApplication
@EnableFeignClients
public class OrderApplication {
public static void main(String[] args) {
SpringApplication.run(OrderApplication.class, args);
}
3.编写feign客户端
@FeignClient("userservice")
public interface UserClient {
@GetMapping("/user/{id}")
User findById(@PathVariable("id") Long id);
}
4.用feign客户端代替RestTemplate
@Autowired
private UserClient userClient;
public Order queryOrderById(Long orderId) {
// 1.查询订单
Order order = orderMapper.findById(orderId);
//2.利用Feign远程调用
User user = userClient.findById(order.getUserId());
//3.封装User到Order
order.setUser(user);
// 4.返回
return order;
}
