Java 实体类的id定义方式

(1) id自增一：

@Id
@SequenceGenerator(name="seq",sequenceName="oracle_seq")
@GeneratedValue(strategy=GenerationType.SEQUENCE, generator="seq")
private long id;

 

(2) UUID：

  @Id
  @GenericGenerator(name = "uuid", strategy = "uuid")
  @GeneratedValue(generator = "uuid")
  @Column(length = 32, name = "s_id")
  private String id;

 

(3)普通id：

 

@Id
@Column(length = 20, name = "id")
private String id;

 

eg:
@Entity
@Table(name = "b_stationregiontree")
@JsonIgnoreProperties(value = {"hibernateLazyInitializer", "handler", "fieldHandler"})
public class StationRegionTree {

//        @Id
//        @SequenceGenerator(name="seq",sequenceName="oracle_seq")
//        @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="seq")
//        private long id;

        @Id
        @Column(length = 20, name = "id")
        private String id;

        @Column(length = 20, name = "rela_tree_id")
        private String relaTreeId;

        /**
         * 上級
         */
    //    @JsonIgnore
    //    @ManyToOne(fetch = FetchType.LAZY)
        @Column(name = "parent_id")
        private String parent;


        @OneToMany(fetch = FetchType.EAGER, mappedBy = "parent")
        //@OrderBy(value = "code asc")
        private Set<StationRegionTree> children;

        /**
         * 车站基础信息值
         */
        @Column(length = 20, name = "inf_value")
        private String infValue;

    }