GeneratedValue (Java EE 5 SDK)

javax.persistence Annotation Type GeneratedValue

@Target(value={METHOD,FIELD})
@Retention(value=RUNTIME)
public @interface GeneratedValue

Provides for the specification of generation strategies for the values of primary keys. The GeneratedValue annotation may be applied to a primary key property or field of an entity or mapped superclass in conjunction with the Id annotation.

 Example 1:

     @Id
     @GeneratedValue(strategy=SEQUENCE, generator="CUST_SEQ")
     @Column(name="CUST_ID")
     public Long getId() { return id; }

     Example 2:

     @Id
     @GeneratedValue(strategy=TABLE, generator="CUST_GEN")
     @Column(name="CUST_ID")
     Long id;
 

从以下版本开始:

Java Persistence 1.0

strategy

public abstract GenerationType strategy

(Optional) The primary key generation strategy that the persistence provider must use to generate the annotated entity primary key.

默认值:

AUTO

generator

public abstract String generator

(Optional) The name of the primary key generator to use as specified in the SequenceGenerator or TableGenerator annotation.

Defaults to the id generator supplied by persistence provider.

默认值:

""

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