问题原因
缺失@Modifying注解
问题解决
在自定义的修改方法（delete、update）上面除了@Transactional注解和@Query还需要@Modifying注解
Bug重现
org.hibernate.hql.internal.QueryExecutionRequestException: Not supported for DML operations [delete from com.crab.bookol.entity.User u where u.username = ?1]