自动和手动设置ID（PK）生成值

自动和手动设置ID（PK）生成值

您可以为此目的定义您的自定义ID生成器，如本SOAnswer中指出的那样

它的代码如下所示：

@Id@Basic(optional = false)@GeneratedValue(strategy=GenerationType.IDENTITY, generator="IdOrGenerated")@GenericGenerator(name="IdOrGenerated",strategy="....UseIdOrGenerate")@Column(name = "ID", unique = true, nullable = false, precision = 20, scale = 0)public Long getId(){..}

和

  public class UseIdOrGenerate extends IdentityGenerator {        @Override    public Serializable generate(SessionImplementor session, Object obj) throws HibernateException {        if (obj == null) throw new HibernateException(new NullPointerException()) ;        if ((((EntityWithId) obj).getId()) == null) {//id is null it means generate ID Serializable id = super.generate(session, obj) ; return id;        } else { return ((EntityWithId) obj).getId();//id is not null so using assigned id.        }    }}