feat: Member API 구현

src/main/java/com/example/hello/member/MemberController.java

@@ -0,0 +1,28 @@
+package com.example.hello.member;
+
+import com.example.hello.member.domain.Member;
+import com.example.hello.member.dto.MemberResponse;
+import com.example.hello.member.service.MemberService;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RequestMapping("/api/members")
+@RestController
+public class MemberController {
+
+    private final MemberService memberService;
+
+    public MemberController(final MemberService memberService) {
+        this.memberService = memberService;
+    }
+
+    @GetMapping("/{memberId}")
+    public ResponseEntity<MemberResponse> findById(@PathVariable Long memberId) {
+        Member member = memberService.findById(memberId);
+        MemberResponse memberResponse = MemberResponse.from(member);
+        return ResponseEntity.ok(memberResponse);
+    }
+}

src/main/java/com/example/hello/member/domain/Member.java

@@ -0,0 +1,26 @@
+package com.example.hello.member.domain;
+
+public class Member {
+
+    private final Long id;
+    private final String name;
+    private final String imageUrl;
+
+    public Member(final Long id, final String name, final String imageUrl) {
+        this.id = id;
+        this.name = name;
+        this.imageUrl = imageUrl;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public String getImageUrl() {
+        return imageUrl;
+    }
+}

src/main/java/com/example/hello/member/dto/MemberResponse.java

@@ -0,0 +1,25 @@
+package com.example.hello.member.dto;
+
+
+import com.example.hello.member.domain.Member;
+
+public class MemberResponse {
+
+    private final Long id;
+    private final String name;
+    private final String imageUrl;
+
+    public MemberResponse(final Long id, final String name, final String imageUrl) {
+        this.id = id;
+        this.name = name;
+        this.imageUrl = imageUrl;
+    }
+
+    public static MemberResponse from(final Member member) {
+        return new MemberResponse(
+                member.getId(),
+                member.getName(),
+                member.getImageUrl()
+        );
+    }
+}

src/main/java/com/example/hello/member/repository/MemberRepository.java

@@ -0,0 +1,9 @@
+package com.example.hello.member.repository;
+
+import com.example.hello.member.domain.Member;
+import java.util.Optional;
+
+public interface MemberRepository {
+
+    Optional<Member> findById(Long memberId);
+}

src/main/java/com/example/hello/member/repository/MockMemberRepository.java

@@ -0,0 +1,22 @@
+package com.example.hello.member.repository;
+
+import com.example.hello.member.domain.Member;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public class MockMemberRepository implements MemberRepository {
+
+    private final Map<Long, Member> members;
+
+    public MockMemberRepository() {
+        this.members = new HashMap<>();
+    }
+
+    @Override
+    public Optional<Member> findById(final Long memberId) {
+        return Optional.ofNullable(members.get(memberId));
+    }
+}

src/main/java/com/example/hello/member/service/MemberService.java

@@ -0,0 +1,8 @@
+package com.example.hello.member.service;
+
+import com.example.hello.member.domain.Member;
+
+public interface MemberService {
+
+    Member findById(Long memberId);
+}

src/main/java/com/example/hello/member/service/MockMemberService.java

@@ -0,0 +1,21 @@
+package com.example.hello.member.service;
+
+import com.example.hello.member.domain.Member;
+import com.example.hello.member.repository.MemberRepository;
+import org.springframework.stereotype.Service;
+
+@Service
+public class MockMemberService implements MemberService {
+
+    private final MemberRepository memberRepository;
+
+    public MockMemberService(final MemberRepository memberRepository) {
+        this.memberRepository = memberRepository;
+    }
+
+    @Override
+    public Member findById(final Long memberId) {
+        return memberRepository.findById(memberId)
+                .orElseThrow(() -> new IllegalArgumentException("Member does not exist"));
+    }
+}