add addItem at interface ItemDao
config xml
implement method addItem at ItemDao
implement method addItem at ItemDaoImpl
implement method addItem at ItemService
implement method addItem at ItemServiceImpl
implement method addItem at ItemController
add judge logic of method addItem at ItemDaoImpl
add modifyItem at ItemDao and ItemDaoImpl
implement method modifyItem at ItemDao
implement method modifyItem at ItemDaoImpl
implement method modifyItem at ItemService
implement method modifyItem at ItemServiceImpl
implement method modifyItem at ItemController
add entity Category
modify addItem at ItemdaoImpl
modify HttpStatus
implement entity Category
add interface CategoryDao
add public