07.http客户端Feign

07.http客户端Feign

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;
    }