How is the result of the @ FeignClient http call handled within the class it annotates?

@FeignClient(name = "china-mobile-api",
             url = "${url.cn.mobile}",
             configuration = FeignConfig.class          
 )
@RequestMapping(value = "/order/v2",
                consumes = {"application/x-www-form-urlencoded;charset=UTF-8"},
                produces = {"*;charset=UTF-8"})
public interface IOrderService{
    @PostMapping("/get_order_info")
    String getOrderInfo(@RequestBody String param);

   
    @PostMapping("/order/is_exist")
    String checkExist(@RequestBody String orderId);
}

for example, in the above code, the return value after calling the http interface is a little complicated. I want to deal with the response in the IOrderService class, and then return a simple value to the external call instead of letting the external call parse the result. Is there anything you can do?