jap设置两个表中oneToMany/ManyToOne

素颜马尾好姑娘i 2022-05-28 10:21 205阅读 0赞

多对一的关系我们通常在多的一方来维护。现在使用tbUser和tbRole来完成例子，一个人只能有一个角色。  
在user表中我们使用ManyToOne注解来完成关系映射，JoinColumn来设置关联的外键在数据库中的名称。

@Entity
    @Table(name = "tb_user")
    @SequenceGenerator(name = "tb_user_sq",sequenceName = "tb_user_sqe")
    public class TbUser extends BaseEntity{ 
    
    
        /** * 用户名 */
        private String userName;
        /** * 登录名 */
        private String loginName;
        /** * 登陆密码 */
        private String passWord;
        /** * 手机号 */
        private String telPhone;
        /** * 一个用户只有一个角色 */
        private TbRole tbRole;
    
        public String getUserName() {
            return userName;
        }
    
        public void setUserName(String userName) {
            this.userName = userName;
        }
    
        public String getLoginName() {
            return loginName;
        }
    
        public void setLoginName(String loginName) {
            this.loginName = loginName;
        }
    
        public String getPassWord() {
            return passWord;
        }
    
        public void setPassWord(String passWord) {
            this.passWord = passWord;
        }
    
        public String getTelPhone() {
            return telPhone;
        }
    
        public void setTelPhone(String telPhone) {
            this.telPhone = telPhone;
        }
    
        @Id
        @Override
        @GeneratedValue(generator = "tb_user_sq",strategy = GenerationType.SEQUENCE)
        public Long getId() {
            return this.id;
        }
        @ManyToOne(cascade = CascadeType.REMOVE)
        @JoinColumn(name = "tb_role_id")
        public TbRole getTbRole() {
            return tbRole;
        }
    
        public void setTbRole(TbRole tbRole) {
            this.tbRole = tbRole;
        }
    }

在role中我们如果想直接使用这个关系的话，同样添加一个外键字段，在外键字段上添加注解OneToMany(mappedBy = “tbRole”)，mappdBy对应的是当前实体在外键实体中的字段名。

@Entity
    @Table(name = "tb_role")
    @SequenceGenerator(name = "tb_role_sq",sequenceName = "tb_role_sqe")
    public class TbRole extends BaseEntity{ 
    
    
        @Override
        @Id
        @GeneratedValue(generator = "tb_role_sq",strategy = GenerationType.SEQUENCE)
        public Long getId() {
            return this.id;
        }
    
        private String roleName;
    
        private List<TbUser> tbUserList=new ArrayList<>();
    
        public String getRoleName() {
            return roleName;
        }
    
        public void setRoleName(String roleName) {
            this.roleName = roleName;
        }
        @OneToMany(mappedBy = "tbRole")
        public List<TbUser> getTbUserList() {
            return tbUserList;
        }
    
        public void setTbUserList(List<TbUser> tbUserList) {
            this.tbUserList = tbUserList;
        }
    }