[Spring] Argument Resolver

Argument Resolver ?

• 컨트롤러 메소드의 인자로 사용자가 임의의 값을 전달하는 방법을 제공하고자할 때 사용하는 방법

User

@Builder
@Getter
public class User {
    private String id;
}

UserArgumentResolver

public class UserArgumentResolver implements HandlerMethodArgumentResolver {
    @Override
    public boolean supportsParameter(MethodParameter parameter) {
        return parameter.getParameterType() == User.class;
    }

    @Override
    public Object resolveArgument(
        MethodParameter parameter,
        ModelAndViewContainer container,
        NativeWebRequest request,
        WebDataBinderFactory webDataBinderFactory
    ) throws Exception {
        return User.builder()
            .id(request.getHeader("id"))
            .build();
    }
}

WebMvcConfig

@Configuration
public class WebMvcConfig implements WebMvcConfigurer {
    @Override
    public void addArgumentResolvers(List<HandlerMethodArgumentResolver> resolvers) {
        resolvers.add(new UserArgumentResolver());
    }
}

UserController

@RestController
public class UserController {
    @GetMapping("/api/user")
    public User getUser(User user) {
        return user;
    }
}

요청

curl --location --request GET 'http://localhost:8080/api/user' \
--header 'id: helloworld'

응답

{
    "id": "helloworld"
}