Feat: json 관련 어노테이션 - @JsonManagedReference & @JsonBackReference

json-util/src/main/java/com/example/demo/JsonUtilApplication.java

@@ -1,7 +1,11 @@
 package com.example.demo;
 
+import com.example.demo.domain.Board;
+import com.example.demo.domain.Comment;
 import com.example.demo.domain.Member;
 import com.example.demo.domain.Team;
+import com.example.demo.infrastructure.BoardRepository;
+import com.example.demo.infrastructure.CommentRepository;
 import com.example.demo.infrastructure.MemberRepository;
 import com.example.demo.infrastructure.TeamRepository;
 import org.springframework.boot.CommandLineRunner;
@@ -12,20 +16,32 @@
 @SpringBootApplication
 public class JsonUtilApplication {
 
-	public static void main(String[] args) {
-		SpringApplication.run(JsonUtilApplication.class, args);
-	}
-
-	@Bean
-	public CommandLineRunner commandLineRunner(MemberRepository memberRepository, TeamRepository teamRepository) {
-		return args -> {
-			Team team1 = teamRepository.save(new Team("teamA"));
-			Team team2 = teamRepository.save(new Team("teamB"));
-
-			memberRepository.save(new Member(team1, "member1", 10));
-			memberRepository.save(new Member(team2, "member2", 20));
-			memberRepository.save(new Member(team2, "member3", 30));
-		};
-	}
+    public static void main(String[] args) {
+        SpringApplication.run(JsonUtilApplication.class, args);
+    }
+
+    @Bean
+    public CommandLineRunner commandLineRunner(MemberRepository memberRepository,
+                                               TeamRepository teamRepository,
+                                               BoardRepository boardRepository,
+                                               CommentRepository commentRepository) {
+        return args -> {
+            Team team1 = teamRepository.save(new Team("teamA"));
+            Team team2 = teamRepository.save(new Team("teamB"));
+
+            memberRepository.save(new Member(team1, "member1", 10));
+            memberRepository.save(new Member(team2, "member2", 20));
+            memberRepository.save(new Member(team2, "member3", 30));
+
+            Board board1 = boardRepository.save(new Board("title1", "content1"));
+            Board board2 = boardRepository.save(new Board("title2", "content2"));
+
+            commentRepository.save(new Comment(board1, "board1-comment1"));
+            commentRepository.save(new Comment(board1, "board1-comment2"));
+            commentRepository.save(new Comment(board1, "board1-comment3"));
+            commentRepository.save(new Comment(board2, "board2-comment1"));
+            commentRepository.save(new Comment(board2, "board2-comment2"));
+        };
+    }
 
 }

json-util/src/main/java/com/example/demo/application/CustomController.java

@@ -16,6 +16,10 @@
 import com.example.demo.application.dto.jsonview.JsonViewResponse;
 import com.example.demo.application.dto.jsonview.View.DetailResponse;
 import com.example.demo.application.dto.jsonview.View.SummaryResponse;
+import com.example.demo.domain.Board;
+import com.example.demo.domain.Comment;
+import com.example.demo.infrastructure.BoardRepository;
+import com.example.demo.infrastructure.CommentRepository;
 import com.example.demo.infrastructure.MemberRepository;
 import com.example.demo.infrastructure.TeamRepository;
 import com.fasterxml.jackson.annotation.JsonView;
@@ -35,6 +39,8 @@ public class CustomController {
 
     private final MemberRepository memberRepository;
     private final TeamRepository teamRepository;
+    private final BoardRepository boardRepository;
+    private final CommentRepository commentRepository;
 
     @GetMapping("/property")
     public JsonPropertyResponseData getDataUsingJsonProperty() {
@@ -116,5 +122,14 @@ public JsonViewResponse getDataUsingJsonViewByDetail() {
     }
 
 
+    @GetMapping("/managed-reference")
+    public List<Board> getDataUsingJsonManagedReference() {
+        return boardRepository.findAll();
+    }
+
+    @GetMapping("/back-reference")
+    public List<Comment> getDataUsingJsonBackReference() {
+        return commentRepository.findAll();
+    }
 
 }

json-util/src/main/java/com/example/demo/domain/Board.java

@@ -0,0 +1,35 @@
+package com.example.demo.domain;
+
+import com.fasterxml.jackson.annotation.JsonManagedReference;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.OneToMany;
+import java.util.ArrayList;
+import java.util.List;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Entity
+@Data
+@NoArgsConstructor
+@AllArgsConstructor
+public class Board {
+
+    @Id @GeneratedValue
+    private Long id;
+    private String title;
+    private String content;
+
+    @OneToMany(mappedBy = "board")
+    @JsonManagedReference
+    private List<Comment> comments = new ArrayList<>();
+
+    public Board(String title, String content) {
+        this.title = title;
+        this.content = content;
+    }
+}

json-util/src/main/java/com/example/demo/domain/Comment.java

@@ -0,0 +1,32 @@
+package com.example.demo.domain;
+
+import com.fasterxml.jackson.annotation.JsonBackReference;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import jakarta.persistence.ManyToOne;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Entity
+@Data
+@NoArgsConstructor
+@AllArgsConstructor
+public class Comment {
+
+    @Id @GeneratedValue
+    private Long id;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JsonBackReference
+    private Board board;
+
+    private String content;
+
+    public Comment(Board board, String content) {
+        this.board = board;
+        this.content = content;
+    }
+}

json-util/src/main/java/com/example/demo/infrastructure/BoardRepository.java

@@ -0,0 +1,8 @@
+package com.example.demo.infrastructure;
+
+import com.example.demo.domain.Board;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface BoardRepository extends JpaRepository<Board, Long> {
+
+}

json-util/src/main/java/com/example/demo/infrastructure/CommentRepository.java

@@ -0,0 +1,8 @@
+package com.example.demo.infrastructure;
+
+import com.example.demo.domain.Comment;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface CommentRepository extends JpaRepository<Comment, Long> {
+
+}