未找到类型<entityName>的属性<method name>

我有以下实体:

@Entity
@Table(name = "MY_TABLE")
@Data
public class MyTable implements java.io.Serializable {

private static final long serialVersionUID = 3879471087851341216L;

@Id
@Column(name = "MY_ID")
private BigInteger myId;

@Column(name = "ANOTHER_COL")
private String anotherColumn;

然后创建存储库:

@Repository
public interface MyTableRepository extends JpaRepository<MyTable, BigInteger> {

@Query(name = "select count(*) from MyTable where ...")
public Long getCountOf(@Param("myId") BigInteger myId);

但一开始我就知道:

找不到MyTable类型的getCountOf属性

我做错什么了?