IdClass (Java EE 5)

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SUMMARY: REQUIRED | OPTIONAL

DETAIL: ELEMENT

javax.persistence Annotation Type IdClass

@Target(value=TYPE) @Retention(value=RUNTIME) public @interface IdClass

Implements: Annotation

@Target(value=TYPE)
@Retention(value=RUNTIME)

指定映射到实体的多个字段或属性的复合主键类。

主键类中字段或属性的名称必须与实体的主键字段或属性的名称一致，它们的类型也必须相同。

示例：

@IdClass(com.acme.EmployeePK.class)
   @Entity
   public class Employee {
     @Id String empName;
     @Id Date birthDay;
     ...
   }

since

Java Persistence 1.0

英文文档：

Specifies a composite primary key class that is mapped to multiple fields or properties of the entity.

The names of the fields or properties in the primary key class and the primary key fields or properties of the entity must correspond and their types must be the same.

   Example:

   @IdClass(com.acme.EmployeePK.class)
   @Entity
   public class Employee {
     @Id String empName;
     @Id Date birthDay;
     ...
   }