rename CategoryDao to CategoryDaoImpl
rename ProductDao to ProductDaoImpl
rename PromotionDao to PromotionDaoImpl
rename CategoryService to CategoryServiceImpl
rename ProductService to ProductServiceImpl
PromotionService to PromotionServiceImpl
refactor extract interface
refactor extract interface
modify spring-config.xml
modify test ProductServiceTest
modify test barcodeSannerTest
modify barcode inject productService
modify test CategoryServiceTest
modify CategoryServiceImpl inject CategoryDao