회원등록 API // api 개발시 dto를 사용해야하는 이유

1. 전체코드

package jpabook.jpashop.api;

import javax.validation.Valid;
import javax.validation.constraints.NotEmpty;
import jpabook.jpashop.domain.Member;
import jpabook.jpashop.service.MemberService;
import lombok.Data;
import lombok.RequiredArgsConstructor;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;

@RestController //data를 바로 json,xml으로 보냄
@RequiredArgsConstructor
public class MemberApiController {

    private final MemberService memberService;

    @PostMapping("/api/v1/members")
    public CreateMemberResponse saveMemberV1(
            @RequestBody @Valid Member member) {//json 데이터를 member로 바꿔줘, Member클래스로가서 @들 검증해줘
        Long id = memberService.join(member);
        return new CreateMemberResponse(id);
    }
    //문제 : 외부에 엔티티 파라미터 노출은 위험, member 변수명 변경시 api 다 터짐

    //해결 : DTO
    // member 변수명 변경시 컴파일 오류로 알려줌
    @PostMapping("/api/v2/members")
    public CreateMemberResponse saveMemberV2(
            @RequestBody @Valid CreateMemberRequest request) {//json 데이터를 member로 바꿔줘, Member클래스로가서 @들 검증해줘
        Member member = new Member();
        member.setName(request.getName());

        Long id = memberService.join(member);
        return new CreateMemberResponse(id);
    }


    @Data
    static class CreateMemberResponse {
        private Long id;

        public CreateMemberResponse(Long id) {
            this.id = id;
        }
    }

    @Data
    static class CreateMemberRequest {
        @NotEmpty
        private String name;
    }
}

1.