小编Nur*_*sha的帖子

考虑这个示例，其中我创建了两个 JPA 实体并使用 Spring Data JPA 存储库来执行简单的 CRUD -

import java.sql.Timestamp;
import javax.persistence.Version;

@MappedSuperclass
public class AbstractValueObject {
    @Id
    @GeneratedValue
    private Long id;

    @Version
    @Column(name = "time_stamp")
    private Timestamp version;

    public Long getId() {
        return id;
    }

    @Override
    public String toString() {
        if (id == null) {
            return "";
        }

        return id.toString();
    }
}

@Entity
@Table(name = "demo")
public class Demo extends AbstractValueObject {
    private String name;

    @OneToMany(cascade = CascadeType.ALL, orphanRemoval = true, mappedBy = "demo")
    private List<Owner> owners;

    public …