java商城项目实战之购物车功能实现

@Service 
public class CartServiceImpl implements CartService { 
//服务url 
@Value("${REST_BASE_URL}") 
private String REST_BASE_URL; 
//商品服务url 
@Value("${ITEMS_ITEM_URL}") 
private String ITEMS_ITEM_URL; 
//COOKIE中购物车商品对应的key 
@Value("${CART_ITEMS_LIST_KEY}") 
private String CART_ITEMS_LIST_KEY; 
//购物车cookie生存期 
@Value("${CART_ITEMS_EXPIRE_TIME}") 
private Integer CART_ITEMS_EXPIRE_TIME; 
/** 
 * 添加购物车商品 
 * <p>Title: addItem</p> 
 * <p>Description: </p> 
 * @param itemId 
 * @param request 
 * @param response 
 * @return 
 * @see com.taotao.portal.service.CartService#addItem(java.lang.Long, javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) 
 */ 
@Override 
public TaotaoResult addItem(Long itemId, HttpServletRequest request, HttpServletResponse response) { 
//根据商品id查询商品信息 
Item item = getItemById(itemId); 
if (item == null) return TaotaoResult.build(400, "未查询到该商品信息"); 
//取cookie中购物车商品列表 
List<Item> cartItems = getItemListFromCookie(request); 
//判断该商品是否存在于购物车中 
boolean itemExists = false; 
for (Item i : cartItems) { 
if (i.getId().longValue() == itemId.longValue()) { 
//购物车中有此商品 
i.setNum(i.getNum() + 1); 
itemExists = true; 
break; 
} 
} 
//如果商品不存在于购物车则向购物车商品列表中添加一个商品 
if (! itemExists) { 
//设置数量为1 
item.setNum(1); 
//把商品添加到购物车 
cartItems.add(item); 
} 
//把购物车信息写入cookie中 
CookieUtils.setCookie(request, response, CART_ITEMS_LIST_KEY, JsonUtils.objectToJson(cartItems), CART_ITEMS_EXPIRE_TIME, true); 
return TaotaoResult.ok(cartItems); 
} 
private Item getItemById(Long itemId) { 
//根据商品id查询商品信息 
String resultStr = HttpClientUtil.doGet(REST_BASE_URL + ITEMS_ITEM_URL + itemId); 
//转换成taotaoResult 
TaotaoResult result = TaotaoResult.formatToPojo(resultStr, Item.class); 
//取商品信息 
Item item = null; 
if (result.getStatus() == 200) { 
item = (Item) result.getData(); 
} 
return item; 
} 
private List<Item> getItemListFromCookie(HttpServletRequest request) { 
//取cookie中购物车商品列表 
String cartItemsStr = CookieUtils.getCookieValue(request, CART_ITEMS_LIST_KEY, true); 
//如果不为空那么就转换成java对象 
List<Item> cartItems = null; 
if (!StringUtils.isBlank(cartItemsStr)) { 
cartItems = JsonUtils.jsonToList(cartItemsStr, Item.class); 
} else { 
cartItems = new ArrayList<>(); 
} 
return cartItems; 
} 
} 

@Controller 
@RequestMapping("/cart") 
public class CartController { 
 
@Autowired 
private CartService cartService; 
@RequestMapping("/add/{itemId}") 
public String addItem(@PathVariable Long itemId, 
HttpServletRequest request, HttpServletResponse response, Model model) { 
//添加商品信息 
TaotaoResult result = cartService.addItem(itemId, request, response); 
//错误信息 
if (result.getStatus() != 200) { 
model.addAttribute("message", result.getMsg()); 
return "error/exception"; 
} 
//把购物车中的商品传递给页面 
model.addAttribute("cartList", result.getData()); 
return "cart"; 
} 
} 

/** 
 * 取购物车列表 
 * <p> 
 * Title: getCartItemsList 
 * </p> 
 * <p> 
 * Description: 
 * </p> 
 * 
 * @return 
 * @see com.taotao.portal.service.CartService#getCartItemsList() 
 */ 
@Override 
public List<Item> getCartItemsList(HttpServletRequest request) { 
// 从cookie中取商品列表 
List<Item> itemsList = getItemListFromCookie(request); 
return itemsList; 
} 

@RequestMapping("/cart") 
public String showCart(HttpServletRequest request, Model mode) { 
//取购物车信息 
List<Item> list = cartService.getCartItemsList(request); 
mode.addAttribute("cartList", list); 
return "cart"; 
} 

/** 
 * 修改指定商品的数量 
 * <p>Title: changeItemNum</p> 
 * <p>Description: </p> 
 * @param itemId 
 * @param num 
 * @param request 
 * @param response 
 * @return 
 * @see com.taotao.portal.service.CartService#changeItemNum(long, int, javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) 
 */ 
@Override 
public TaotaoResult changeItemNum(long itemId, int num, HttpServletRequest request, HttpServletResponse response) { 
//从cookie中取商品列表 
List<Item> list = getItemListFromCookie(request); 
//从商品列表中找到要修改数量的商品 
for (Item item : list) { 
if (item.getId() == itemId) { 
//找到商品，修改数量 
item.setNum(num); 
break; 
} 
} 
//把商品信息写入cookie 
CookieUtils.setCookie(request, response, CART_ITEMS_LIST_KEY, JsonUtils.objectToJson(list), CART_ITEMS_EXPIRE_TIME, true); 
return TaotaoResult.ok(); 
} 

@RequestMapping("/update/num/{itemId}/{num}") 
@ResponseBody 
public TaotaoResult updateNumById(@PathVariable Long itemId, @PathVariable Integer num, 
HttpServletRequest request, HttpServletResponse response) { 
TaotaoResult result = cartService.changeItemNum(itemId, num, request, response); 
return result; 
} 

/** 
 * 删除购物车中的商品 
 * <p> 
 * Title: deleteItem 
 * </p> 
 * <p> 
 * Description: 
 * </p> 
 * 
 * @param itemId 
 * @param request 
 * @param response 
 * @return 
 * @see com.taotao.portal.service.CartService#deleteItem(java.lang.Long, 
 * javax.servlet.http.HttpServletRequest, 
 * javax.servlet.http.HttpServletResponse) 
 */ 
@Override 
public List<Item> deleteItem(Long itemId, HttpServletRequest request, HttpServletResponse response) { 
List<Item> itemsList = getCartItemsList(request); 
// 找到购物车中的商品，并删除之 
for (Item item : itemsList) { 
if (item.getId().longValue() == itemId.longValue()) { 
itemsList.remove(item); 
break; 
} 
} 
// 更新cookie中的购物车数据 
CookieUtils.setCookie(request, response, CART_ITEMS_LIST_KEY, JsonUtils.objectToJson(itemsList), CART_ITEMS_EXPIRE_TIME, true); 
return itemsList; 
} 

@RequestMapping("/delete/{itemId}") 
public String deleteItemById(@PathVariable Long itemId, 
HttpServletRequest request, HttpServletResponse response, 
Model model) { 
List<Item> list = cartService.deleteItem(itemId, request, response); 
model.addAttribute("cartList", list); 
return "cart"; 
}