id生成：
hibernate内不可使用的id生成器可见代码
使用@GeneratedValue
1 正对不同的数据库可以同时使用
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
2 针对mysql
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
3 针对oracle
@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE,generator="s_gen")
@SequenceGenerator(name="s_gen",sequenceName="s_seq")
说明：@GeneratedValue()的strategy属性支持5中id生成器：除上面3中外还有GenerationType.TABLE
2配合使用@GenericGenerator 不单独使用
hibernate内不可使用的id生成器可见代码
GENERATORS.put( "uuid", UUIDHexGenerator.class );
GENERATORS.put( "hilo", TableHiLoGenerator.class );
GENERATORS.put( "assigned", Assigned.class );
GENERATORS.put( "identity", IdentityGenerator.class );
GENERATORS.put( "select", SelectGenerator.class );
GENERATORS.put( "sequence", SequenceGenerator.class );
GENERATORS.put( "seqhilo", SequenceHiLoGenerator.class );
GENERATORS.put( "increment", IncrementGenerator.class );
GENERATORS.put( "foreign", ForeignGenerator.class );
GENERATORS.put( "guid", GUIDGenerator.class );
GENERATORS.put( "uuid.hex", UUIDHexGenerator.class ); // uuid.hex is deprecated
GENERATORS.put( "sequence-identity", SequenceIdentityGenerator.class );
)
如果想要不同的表使用相同的主键生成器，可以把他的generator的name属性设为相同即可
例如：
@GeneratedValue(name="id1")
@GenericGenerator(name="id1",strategy="identity")
1、native
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name = "paymentableGenerator", strategy = "native")
2、uuid
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name = "paymentableGenerator", strategy = "uuid")
3、hilo
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name = "paymentableGenerator", strategy = "hilo")
4、assigned
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name = "paymentableGenerator", strategy = "assigned")
5、identity
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name = "paymentableGenerator", strategy = "identity")
6、select
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name="select", strategy="select", parameters = { @Parameter(name = "key", value = "idstoerung") })
7、sequence
Java代码
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name = "paymentableGenerator", strategy = "sequence", parameters = { @Parameter(name = "sequence", value = "seq_payablemoney") })
8、seqhilo
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name = "paymentableGenerator", strategy = "seqhilo", parameters = { @Parameter(name = "max_lo", value = "5") })
9、increment
Java代码
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name = "paymentableGenerator", strategy = "increment")