Sakura-Dress/sakura_dress_RP/textures/item_texture.json

{
   "resource_pack_name": "vanilla",
   "texture_name": "atlas.items",
   "texture_data": {
      "maozi": {
         "textures": "textures/items/dress2"
      },
      "xueyuan": {
         "textures": "textures/items/xueyuan"
      }
   }
}