基于Feigh发送Http请求，替代RestTemplate

下载依赖

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>

需要在启动类上开启配置，Feigh默认自带负载均衡配置

@SpringBootApplication
@EnableFeignClients
public class OrderApplication {

    public static void main(String[] args) {
        SpringApplication.run(OrderApplication.class, args);
    }

}

新建一个接口

@FeignClient("userservice")//提供者的服务名
public interface UserClients {

    @GetMapping("/user/{id}")
    User findById(@PathVariable("id") Long id);
}

 直接使用即可

@Autowired
    private UserClients userClients;

    public Order queryOrderById(Long orderId) {
        // 1.查询订单
        Order order = orderMapper.findById(orderId);  //忽略,和知识点无关
        order.setUser(userClients.findById(orderId));

        return order;
    }