[스프링 입문] 섹션 3, 4, 5

1. 회원 관리

비즈니스 요구사항
가장 단순한 걸로 개발 시작 !!

회원 도메인과 레포지토리

• 회원 객체

package hello.hellospring.domain;

public class Member {
    private Long id; //고객이 아니라 시스템이 저장하는 id
    private String name; //이름

    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}

• 회원 레포지토리 인터페이스

package hello.hellospring.repository;
import hello.hellospring.domain.Member;
import java.util.List;
import java.util.Optional;
public interface MemberRepository {
    Member save(Member member);
    Optional<Member> findById(Long id); //없으면 null로 반환이 되는데 optional로 감싸줌
    Optional<Member> findByName(String name);
    List<Member> findAll();
}

-회원 레포지토리 메모리 구현체

package hello.hellospring.repository;
import hello.hellospring.domain.Member;
import java.util.*;
/**
 * 동시성 문제가 고려되어 있지 않음, 실무에서는 ConcurrentHashMap, AtomicLong 사용 고려
 */
public class MemoryMemberRepository implements MemberRepository {
    private static Map<Long, Member> store = new HashMap<>(); //저장을 하기 위한 변수, 실무에서는 concurrent로
    private static long sequence = 0L;
    @Override
    public Member save(Member member) {
        member.setId(++sequence); //시퀀스 값 올려줌
        store.put(member.getId(), member);
        return member;
    }
    @Override
    public Optional<Member> findById(Long id) {
        return Optional.ofNullable(store.get(id)); //null값을 감싸주기 위해성
    }
    @Override
    public List<Member> findAll() {
        return new ArrayList<>(store.values()); //member 반환
    }
    @Override
    public Optional<Member> findByName(String name) {
        return store.values().stream()
                .filter(member -> member.getName().equals(name)) //같은 name만 반환
                .findAny();
    }
}

테스트 케이스 작성

    public void clearStore() { //MemoryMemberReposity.java에 추가
        store.clear();
    }

package hello.hellospring.repository;
import hello.hellospring.domain.Member;
import org.assertj.core.api.Assertions;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.Test;
import java.util.List;
import java.util.Optional;
import static org.assertj.core.api.Assertions.*;
class MemoryMemberRepositoryTest { //클래스 레벨만 따로 테스트 가능
    MemoryMemberRepository repository = new MemoryMemberRepository();

    @AfterEach
    public void afterEach() { //실행이 끝날때마다
        repository.clearStore(); //계속 clearStore
    }


    @Test //테스트로 실행, 아무런 내용 없이도 메소드 실행 가능
    public void save() {
        //given
        Member member = new Member();
        member.setName("spring"); //command+shift+enter 단축키 배움
        //when
        repository.save(member);
        //then
        Member result = repository.findById(member.getId()).get(); //optional에서 값 꺼내기
        assertThat(result).isEqualTo(member); // static import
        //Assertions.assertEquals(member, result);

    }

    @Test
    public void findByName() {
        //given
        Member member1 = new Member();
        member1.setName("spring1");
        repository.save(member1);

        Member member2 = new Member();
        member2.setName("spring2");
        repository.save(member2);
        //when
        Member result = repository.findByName("spring1").get(); //spring2를 넣으면 다른 객체라고 경고
        //then
        assertThat(result).isEqualTo(member1);
    }

    @Test
    public void findAll() {
        //given
        Member member1 = new Member();
        member1.setName("spring1");
        repository.save(member1);

        Member member2 = new Member();
        member2.setName("spring2");
        repository.save(member2);
        //when
        List<Member> result = repository.findAll();
        //then
        assertThat(result.size()).isEqualTo(2);
    }

}

회원 서비스 개발
실제 비즈니스 로직을 작성하는 !..

package hello.hellospring.service;

import hello.hellospring.domain.Member;
import hello.hellospring.repository.MemberRepository;
import hello.hellospring.repository.MemoryMemberRepository;

import java.util.List;
import java.util.Optional;

public class MemberService {
    private final MemberRepository memberRepository = new
            MemoryMemberRepository();

    //회원가입
    public Long join(Member member) {
        validateDuplicateMember(member); //중복 회원 검증
        memberRepository.save(member);
        return member.getId();//result.orElseGet()
    }
    private void validateDuplicateMember(Member member) {
        memberRepository.findByName(member.getName())
                .ifPresent(m -> { //null이 아니면, optional이라서 가능한 일
                    throw new IllegalStateException("이미 존재하는 회원입니다.");
                });
    }
    //회원조회
    public List<Member> findMembers() {
        return memberRepository.findAll();
    }
    public Optional<Member> findOne(Long memberId) {
        return memberRepository.findById(memberId);
    }
}

테스트 !!
클래스 명에서 command + shift + t

private final MemberRepository memberRepository;

    public MemberService(MemberRepository memberRepository) {
        this.memberRepository = memberRepository;
    }

-> MemberService.java constructor 수정사항

package hello.hellospring.service;

import hello.hellospring.domain.Member;
import hello.hellospring.repository.MemoryMemberRepository;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import static org.assertj.core.api.Assertions.*;
import static org.junit.jupiter.api.Assertions.*;
class MemberServiceTest {
    MemberService memberService;
    MemoryMemberRepository memberRepository;
    @BeforeEach
    public void beforeEach() {
        memberRepository = new MemoryMemberRepository();
        memberService = new MemberService(memberRepository);
    }
    @AfterEach
    public void afterEach() {
        memberRepository.clearStore();
    }
    @Test
    public void 회원가입() throws Exception { //테스트니까 과감하게 한글로 해도 됨
        //Given
        Member member = new Member();
        member.setName("hello");
        //When
        Long saveId = memberService.join(member); //검증
        //Then
        Member findMember = memberRepository.findById(saveId).get();
        assertEquals(member.getName(), findMember.getName());
    }
    @Test
    public void 중복_회원_예외() throws Exception {
        //Given
        Member member1 = new Member();
        member1.setName("spring");
        Member member2 = new Member();
        member2.setName("spring");
        //When
        memberService.join(member1);
        IllegalStateException e = assertThrows(IllegalStateException.class,
                () -> memberService.join(member2));//예외가 발생해야 한다.
        assertThat(e.getMessage()).isEqualTo("이미 존재하는 회원입니다.");
        /*
        memberService.join(member1);
        try {
        memberService.join(member2);
        fail();
        } catch (IllegalStateException e) {
        assertThat(e.getMessage()).isEqualTo("이미 존재하는 회원입니다.");
        }
         */
    }
}

2. 스프링 빈과 의존관계

컴포넌트 스캔과 자동 의존관계 설정
컨트롤러와 클래스 간의 연결 -> could not be found 생김 -> @Service 추가 (등록하는 과정) -> @Repository도 마찬가지 -> 의존관계 주입을 위해 MemberService.java에 @AutoWired추가 (생성자 도출 및 컨테이너에 주입)

스프링 빈
스프링 빈 등록 방법
1. 컴포넌트 스캔 : 골뱅이파티(@Component)
2. 자바 코드 //하위 패키지가 아닌 친구들은 등록되지 않는 위험성이 있으니 ..

package hello.hellospring;
import hello.hellospring.repository.MemberRepository;
import hello.hellospring.repository.MemoryMemberRepository;
import hello.hellospring.service.MemberService;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class SpringConfig {
 @Bean
 public MemberService memberService() {
 return new MemberService(memberRepository());
 }
 @Bean
 public MemberRepository memberRepository() {
return new MemoryMemberRepository();
 }
}

• 필드주입 -> 생성자를 빼고 냅다 주입하기 (별로 좋지 않음)
• set주입 -> 나중에 호출, 누군가가 호출했을때 public이어야만 함

3. 웹 MVC 개발

회원 웹 기능 - 홈 화면 추가
회원 웹 기능 - 등록

@PostMapping(value = "/members/new")
    public String create(MemberForm form) {
        Member member = new Member();
        member.setName(form.getName());
        memberService.join(member);
        return "redirect:/";
    }

회원 웹 기능 - 조회

@GetMapping(value = "/members")
    public String list(Model model) {
        List<Member> members = memberService.findMembers();
        model.addAttribute("members", members);
        return "members/memberList";
    }