ソリッド設計

ドメインモデルの例

@Entity
@Getter @Setter
@NoArgsConstructor(access = AccessLevel.PROTECTED)
@ToString(of = {"id","username","age"})
public class Member {

    @Id @GeneratedValue
    @Column(name ="member_id")
    private Long id;
    private String username;
    private int age;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "team_id")
    private Team team;

    public Member(String username, int age, Team team) {
        this.username = username;
        this.age = age;
        if(team != null){
            changeTeam(team);
        }
    }

	//연관관계 편의 메소드
    public void changeTeam(Team team) {
        this.team = team;
        team.getMembers().add(this);
    }

    public Member(String username, int age) {
        this(username,age,null);
    }

    public Member(String username) {
        this(username,0);
    }
}

@Getter @Setter
@Entity
@NoArgsConstructor(access = AccessLevel.PROTECTED)
@ToString(of = {"id", "name"})
public class Team {

    @Id @GeneratedValue
    private Long id;
    private String name;

    @OneToMany(mappedBy = "team")
    private List<Member> members = new ArrayList<>();

    public Team(String name){
        this.name = name;
    }
}