hibernate 自定义排序

实现hibernate自定义排序，要继承Order 类

public class NumberOrder extends Order{
	private String propertyName;
	private String ascending;
	public NumberOrder(String propertyName,boolean ascending){
 		super(propertyName,ascending);
  		this.propertyName=propertyName;
  		this.ascending=ascending;
 	}
 	@Override
	 public String toSqlString(Criteria criteria,CriteriaQuery criteriaQuery) throws HibernateException{
	   	String[] columns=criteriaQuery.getColumnsUsingProjection(criteria,propertyName);
	   	return " to_number("+columns[0]+") "+(ascending ? " asc":" desc");
	 }
}