基于按annotation的hibernate主键生成策略
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自定义主键生成策略,由@GenericGenerator实现。
hibernate在JPA的基础上进行了扩展,可以用一下方式引入hibernate独有的主键生成策略,就是通过@GenericGenerator加入的。
比如说,JPA标准用法
就可以用hibernate特有以下用法来实现
@GenericGenerator的定义:
name属性指定生成器名称。
strategy属性指定具体生成器的类名。
parameters得到strategy指定的具体生成器所用到的参数。
对于这些hibernate主键生成策略和各自的具体生成器之间的关系,在org.hibernate.id.IdentifierGeneratorFactory中指定了,
上面十二种策略,加上native,hibernate一共默认支持十三种生成策略。
1、native
2、uuid
3、hilo
4、assigned
5、identity
6、select
7、sequence
8、seqhilo
9、increment
10、foreign
注意:直接使用@PrimaryKeyJoinColumn 报错(?)
12、uuid.hex
13、sequence-identity
四、通过@GenericGenerator自定义主键生成策略
如果实际应用中,主键策略为程序指定了就用程序指定的主键(assigned),没有指定就从sequence中取。
明显上面所讨论的策略都不满足,只好自己扩展了,集成assigned和sequence两种策略。
实际应用中,定义同sequence。
值得注意的是,定义的这种策略,就像打开了潘多拉魔盒,非常不可控。正常情况下,不建议这么做。
hibernate在JPA的基础上进行了扩展,可以用一下方式引入hibernate独有的主键生成策略,就是通过@GenericGenerator加入的。
比如说,JPA标准用法
Java代码
- @Id
- @GeneratedValue(GenerationType.AUTO)
@Id @GeneratedValue(GenerationType.AUTO)
就可以用hibernate特有以下用法来实现
Java代码
- @GeneratedValue(generator = "paymentableGenerator")
- @GenericGenerator(name = "paymentableGenerator", strategy ="assigned")
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name = "paymentableGenerator", strategy = "assigned")
@GenericGenerator的定义:
Java代码
- @Target({PACKAGE, TYPE, METHOD, FIELD})
- @Retention(RUNTIME)
- public @interface GenericGenerator {
- String name();
- String strategy();
- Parameter[] parameters() default {};
- }
@Target({PACKAGE, TYPE, METHOD, FIELD}) @Retention(RUNTIME) public @interface GenericGenerator { String name(); String strategy(); Parameter[] parameters() default {}; }
name属性指定生成器名称。
strategy属性指定具体生成器的类名。
parameters得到strategy指定的具体生成器所用到的参数。
对于这些hibernate主键生成策略和各自的具体生成器之间的关系,在org.hibernate.id.IdentifierGeneratorFacto
Java代码
- static {
"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 deprecatedGENERATORS.put( "sequence-identity", SequenceIdentityGeneratoGENERATORS.put( r. class);- }
static { 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 deprecatedr.class); }
上面十二种策略,加上native,hibernate一共默认支持十三种生成策略。
1、native
Java代码
- @GeneratedValue(generator = "paymentableGenerator")
- @GenericGenerator(name = "paymentableGenerator", strategy ="native")
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name = "paymentableGenerator", strategy = "native")
2、uuid
Java代码
- @GeneratedValue(generator = "paymentableGenerator")
- @GenericGenerator(name = "paymentableGenerator", strategy ="uuid")
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name = "paymentableGenerator", strategy = "uuid")
3、hilo
Java代码
- @GeneratedValue(generator = "paymentableGenerator")
- @GenericGenerator(name = "paymentableGenerator", strategy ="hilo")
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name = "paymentableGenerator", strategy = "hilo")
4、assigned
Java代码
- @GeneratedValue(generator = "paymentableGenerator")
- @GenericGenerator(name = "paymentableGenerator", strategy ="assigned")
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name = "paymentableGenerator", strategy = "assigned")
5、identity
Java代码
- @GeneratedValue(generator = "paymentableGenerator")
- @GenericGenerator(name = "paymentableGenerator", strategy ="identity")
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name = "paymentableGenerator", strategy = "identity")
6、select
Java代码
- @GeneratedValue(generator = "paymentableGenerator")
- @GenericGenerator(name="select", strategy="select",
@Parameter(name ="key", value = "idstoerung") })parameters = {
@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",
@Parameter(name = "sequence", value ="seq_payablemoney") })parameters = {
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name = "paymentableGenerator", strategy = "sequence", parameters = { @Parameter(name = "sequence", value = "seq_payablemoney") })
8、seqhilo
Java代码
- @GeneratedValue(generator = "paymentableGenerator")
- @GenericGenerator(name = "paymentableGenerator", strategy ="seqhilo",
@Parameter(name = "max_lo", value ="5") })parameters = {
@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")
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name = "paymentableGenerator", strategy = "increment")
10、foreign
Java代码
- @GeneratedValue(generator = "idGenerator")
- @GenericGenerator(name = "idGenerator", strategy ="foreign",
@Parameter(name = "property", value ="employee") })parameters = {
@GeneratedValue(generator = "idGenerator") @GenericGenerator(name = "idGenerator", strategy = "foreign", parameters = { @Parameter(name = "property", value = "employee") })
注意:直接使用@PrimaryKeyJoinColumn 报错(?)
Java代码
- @OneToOne(cascade = CascadeType.ALL)
- @PrimaryKeyJoinColumn
@OneToOne(cascade = CascadeType.ALL) @PrimaryKeyJoinColumn例如
Java代码
- @Entity
- public class Employee {
@Id Integer id; @OneToOne @PrimaryKeyJoinColumnEmployeeInfo info; ... - }
@Entity public class Employee { @Id Integer id; @OneToOne @PrimaryKeyJoinColumn EmployeeInfo info; ... }应该为
Java代码
- @Entity
- public class Employee {
@Id @GeneratedValue(generator = "idGenerator") @GenericGenerator(name = "idGenerator", strategy = "foreign", @Parameter(name = "property", value ="info") })parameters = { Integer id; @OneToOneEmployeeInfo info; ... - }
@Entity public class Employee { @Id @GeneratedValue(generator = "idGenerator") @GenericGenerator(name = "idGenerator", strategy = "foreign", parameters = { @Parameter(name = "property", value = "info") }) Integer id; @OneToOne EmployeeInfo info; ... }11、guid
Java代码
- @GeneratedValue(generator = "paymentableGenerator")
- @GenericGenerator(name = "paymentableGenerator", strategy ="guid")
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name = "paymentableGenerator", strategy = "guid")
12、uuid.hex
Java代码
- @GeneratedValue(generator = "paymentableGenerator")
- @GenericGenerator(name = "paymentableGenerator", strategy ="uuid.hex")
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name = "paymentableGenerator", strategy = "uuid.hex")
13、sequence-identity
Java代码
- @GeneratedValue(generator = "paymentableGenerator")
- @GenericGenerator(name = "paymentableGenerator", strategy ="sequence-identity",
@Parameter(name = "sequence", value ="seq_payablemoney") })parameters = {
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name = "paymentableGenerator", strategy = "sequence-identity", parameters = { @Parameter(name = "sequence", value = "seq_payablemoney") })
四、通过@GenericGenerator自定义主键生成策略
如果实际应用中,主键策略为程序指定了就用程序指定的主键(assigned),没有指定就从sequence中取。
明显上面所讨论的策略都不满足,只好自己扩展了,集成assigned和sequence两种策略。
Java代码
- public class AssignedSequenceGenerato
r extends SequenceGenerator implements - PersistentIdentifierGene
rator, Configurable { - private String entityName;
- public void configure(Type type, Properties params, Dialect dialect)throws MappingException {
entityName = params.getProperty(ENTITY_NAME); if (entityName==null) { throw new MappingException("no entity name");} super.configure(type, params, dialect);- }
- public Serializable generate(SessionImplementor session, Object obj)
throws HibernateException {Serializable id = session.getEntityPersister( entityName, obj ) .getIdentifier( obj, session.getEntityMode() ); if (id==null) { super.generate(session, obj);id = } return id;- }
- }
public class AssignedSequenceGenerator extends SequenceGenerator implements PersistentIdentifierGene rator, Configurable { private String entityName; public void configure(Type type, Properties params, Dialect dialect) throws MappingException { entityName = params.getProperty(ENTITY_NAME); if (entityName==null) { throw new MappingException("no entity name"); } super.configure(type, params, dialect); } public Serializable generate(SessionImplementor session, Object obj) throws HibernateException { Serializable id = session.getEntityPersister( entityName, obj ) .getIdentifier( obj, session.getEntityMode() ); if (id==null) { id = super.generate(session, obj); } return id; } }
实际应用中,定义同sequence。
Java代码
- @GeneratedValue(generator = "paymentableGenerator")
- @GenericGenerator(name = "paymentableGenerator", strategy ="AssignedSequenceGenerato
r" , @Parameter(name ="sequence", value = "seq_payablemoney") })parameters = {
@GeneratedValue(generator = "paymentableGenerator") @GenericGenerator(name = "paymentableGenerator", strategy = "AssignedSequenceGenerator", parameters = { @Parameter(name = "sequence", value = "seq_payablemoney") })
值得注意的是,定义的这种策略,就像打开了潘多拉魔盒,非常不可控。正常情况下,不建议这么做。
- 基于annotation的hibernate主键生成策略
- 基于Annotation的Hibernate主键生成策略
- Hibernate基于Annotation的主键生成策略
- 基于Annotation的hibernate主键生成策略
- 基于annotation的hibernate主键生成策略
- 基于annotation的hibernate主键生成策略
- 基于按annotation的hibernate主键生成策略
- 基于按annotation的hibernate主键生成策略
- 基于按annotation的hibernate主键生成策略
- 基于按annotation的hibernate主键生成策略
- 基于按annotation的hibernate主键生成策略
- 基于按annotation的hibernate主键生成策略
- 基于按annotation的hibernate主键生成策略
- 基于按annotation的hibernate主键生成策略
- 基于按annotation的hibernate主键生成策略
- 基于按annotation的hibernate主键生成策略
- 基于按annotation的hibernate主键生成策略
- 基于按annotation的hibernate主键生成策略
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