added key mapper class
added key mapper class

SummerHF/JSONModel,izrie/JSONModel,TerryAsh/JSONModel,cczallen/JSONModel,SampleLiao/JSONModel,LiuShulong/JSONModel,ernestopino/JSONModel,dbachrach/JSONModel,jianwoo/JSONModel,SatanWoo/JSONModel,liuyujing/JSONModel,SanjoDeundiak/JSONModel,johnmyqin/JSONModel,zhou18520786640/JSONModel,NiuMengFei/JSONModel,SongYuJie1989/JSONModel,CareEvolution/JSONModel,db42/JSONModel,chenkaige/JSONModel,kerrmarin/jsonmodel,scottdinggo/JSONModel,billinghamj/JSONModel,liwangbest/JSONModel,billinghamj/JSONModel,jianwoo/JSONModel,ramoslin02/JSONModel,hfossli/JSONModel,xunan623/JSONModel,huiping192/JSONModel,AlJaMa/JSONModel,redlinesolutions/JSONModel,youprofit/JSONModel,jsonmodel/jsonmodel,zwcshy/JSONModel,zwcshy/JSONModel,yunzhongyoulong/JSONModel,MaWenxing/JSONModel,xxclouddd/JSONModel,icanzilb/JSONModel,MellongLau/JSONModel,yarec/JSONModel,iwakevin/JSONModel,dalu93/JSONModel,ThirakornP/JSONModel