是否有可能为anorm的“on”方法动态创建一个列表?
我有一个带有可选输入的表单,目前我检查每个选项,并创建一个列表与定义的选项,并尝试将其传递给anorm.目前我收到这个编译错误
type mismatch; found : List[java.io.Serializable] required: (Any,anorm.ParameterValue[_])
我不知道如何创建这个列表.
当前代码:
val onList = List( 'school_id = input.school,if(input.rooms isDefined) ('rooms -> input.rooms) else "None",if(input.bathrooms isDefined) ('bathrooms -> input.bathrooms) else "None",if(input.houseType isDefined) ('houseType -> input.houseType) else "None",if(input.priceLow isDefined) ('priceLow -> input.priceLow) else "None",if(input.priceHigh isDefined) ('priceHigh -> input.priceHigh) else "None",if(input.utilities isDefined) ('utilities -> input.utilities) else "None" ).filter(_!="None") sql("SELECT * FROM Houses WHERE " + whereString).on(onList).as(sqlToHouse *)
我试过这样做,因为最初我以为会是一样的
.on('rooms -> input.rooms,'bathroom -> input.bathrooms... etc)
编辑:
代码现在是:
val onList = Seq( ('school_id -> input.school),if(input.rooms isDefined) ('rooms -> input.rooms.get) else None,if(input.bathrooms isDefined) ('bathrooms -> input.bathrooms.get) else None,if(input.houseType isDefined) ('houseType -> input.houseType.get) else None,if(input.priceLow isDefined) ('priceLow -> input.priceLow.get) else None,if(input.priceHigh isDefined) ('priceHigh -> input.priceHigh.get) else None,if(input.utilities isDefined) ('utilities -> input.utilities.get) else None ).filter(_!=None).asInstanceOf[Seq[(Any,anorm.ParameterValue[_])]]
使用sql命令:
sql("SELECT * FROM Houses WHERE " + whereString).on(onList:_*).as(sqlToHouse *)
现在得到例外
[ClassCastException: java.lang.Integer cannot be cast to anorm.ParameterValue]
解决方法
重要的是您必须创建ParameterValue类型的值.
这通常使用toParameterValue()函数完成.
这通常使用toParameterValue()函数完成.
一种方法是创建一个你平展的选项序列:
val onList = Seq( Some('school_id -> input.school),input.rooms.map('rooms -> _),input.bathrooms.map('bathrooms -> _) ).flatten
然后可以将此序列映射到正确的值:
sql( "SELECT * FROM Houses WHERE " + whereString ).on( onList.map(v => v._1 -> toParameterValue(v._2)): _* )
这可以简化为:
val onList = Seq( Some('school_id -> input.school),input.bathrooms.map('bathrooms -> _) ).flatMap(_.map(v => v._1 -> toParameterValue(v._2))) sql( "SELECT * FROM Houses WHERE " + whereString ).on( onList: _* )
或者也许最简单的@R_301_463@案是:
val onList = Seq( Some('school_id -> toParameterValue(input.school)),input.rooms.map('rooms -> toParameterValue(_)),input.bathrooms.map('bathrooms -> toParameterValue(_)) ).flatten sql( "SELECT * FROM Houses WHERE " + whereString ).on( onList: _* )