optimize code style, add some comments
optimize code style, add some comments

xutingting02/etpl,yibuyisheng/etpl,yibuyisheng/etpl,xutingting02/etpl,xutingting02/etpl,noikiy/etpl,longze/etpl,noikiy/etpl,ecomfe/etpl,ecomfe/etpl,yibuyisheng/etpl,longze/etpl,hadesdu/etpl,noikiy/etpl,ecomfe/etpl,hadesdu/etpl,longze/etpl,hadesdu/etpl