錯誤org.hibernate.AnnotationException: No identifier specified for entity

AnnotationExceptionNo identifier specified for entity錯誤org.hibernate.AnnotationException: No identifier specified for entityorg.hibernate.AnnotationException: No identifier specified for entity.

報這個異常的原因是因爲pojo類的主鍵沒有註解映射關係(或者沒有主鍵)

解決方案如下:(以下註解寫在get方法上，而非set方法)
@Id 
@GeneratedValue(strategy=GenerationType.IDENTITY)  
@Column(name="ID", unique=true, nullable=false, insertable=true, updatable=false, precision=20, scale=0)

或者

@Id
@GeneratedValue(generator = "paymentableGenerator")    
@GenericGenerator(name = "paymentableGenerator", strategy = "sequence",    
                  parameters = { @Parameter(name = "sequence", value = "TEST_SEQ") })