网上图书商城项目学习笔记-013 添加购物车及我的购物车

一、流程分析

1.购物车模块



2.我的购物车分析



3.添加条目到购物车



二、代码

1.view层

(1）top.jsp

<a href="<c:url value='/CartItemServlet?method=myCart'/>" target="body">我的购物车</a>

(2)desc.jsp

<form id="form1" action="<c:url value='/CartItemServlet'/>" method="post">
<input type="hidden" name="method" value="add"/>
<input type="hidden" name="bid" value="${book.bid }"/>
我要买：<input id="cnt" style="width: 40px;text-align: center;" type="text" name="quantity" value="1"/>件
</form>

(3)list.jsp

<c:choose>
<c:when test="${items eq null }">
<table width="95%" align="center" cellpadding="0" cellspacing="0">
<tr>
<td align="right">
<img align="top" src="<c:url value='/images/icon_empty.png'/>"/>
</td>
<td>
<span class="spanEmpty">您的购物车中暂时没有商品</span>
</td>
</tr>
</table>

<br/>
</c:when>
<c:otherwise>
<br/>

<table width="95%" align="center" cellpadding="0" cellspacing="0">
<tr align="center" bgcolor="#efeae5">
<td align="left" width="50px">
<input type="checkbox" id="selectAll" checked="checked"/><label for="selectAll">全选</label>
</td>
<td colspan="2">商品名称</td>
<td>单价</td>
<td>数量</td>
<td>小计</td>
<td>操作</td>
</tr>

<c:forEach items="${items }" var="item">

<tr align="center">
<td align="left">
<input value="12345" type="checkbox" name="checkboxBtn" checked="checked"/>
</td>
<td align="left" width="70px">
<a class="linkImage" href="<c:url value='/jsps/book/desc.jsp'/>"><img border="0" width="54" align="top" src="<c:url value='${item.book.image_b }'/>"/></a>
</td>
<td align="left" width="400px">
<a href="<c:url value='/jsps/book/desc.jsp'/>"><span>${item.book.bname }</span></a>
</td>
<td><span>¥<span class="currPrice" id="12345CurrPrice">${item.book.currPrice }</span></span></td>
<td>
<a class="jian" id="12345Jian"></a><input class="quantity" readonly="readonly" id="12345Quantity" type="text" value="${item.quantity }"/><a class="jia" id="12345Jia"></a>
</td>
<td width="100px">
<span class="price_n">¥<span class="subTotal" id="12345Subtotal">${item.getSubTotal() }</span></span>
</td>
<td>
<a href="<c:url value='/jsps/cart/list.jsp'/>">删除</a>
</td>
</tr>
</c:forEach>

<tr>
<td colspan="4" class="tdBatchDelete">
<a href="javascript:alert('批量删除成功');">批量删除</a>
</td>
<td colspan="3" align="right" class="tdTotal">
<span>总计：</span><span class="price_t">¥<span id="total"></span></span>
</td>
</tr>
<tr>
<td colspan="7" align="right">
<a href="<c:url value='/jsps/cart/showitem.jsp'/>" id="jiesuan" class="jiesuan"></a>
</td>
</tr>
</table>
<form id="form1" action="<c:url value='/jsps/cart/showitem.jsp'/>" method="post">
<input type="hidden" name="cartItemIds" id="cartItemIds"/>
<input type="hidden" name="method" value="loadCartItems"/>
</form>
</c:otherwise>
</c:choose>

2.servlet层

(1）CartItemServlet.java

public class CartItemServlet extends BaseServlet {
private CartItemService service = new CartItemService();

/**
* 添加购物车条目
* @param req
* @param resp
* @return
* @throws ServletException
* @throws IOException
*/
public String add(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
Map map = req.getParameterMap();
CartItem item = CommonUtils.toBean(map, CartItem.class);
Book book = CommonUtils.toBean(map, Book.class);
User user = (User) req.getSession().getAttribute("sessionUser");
item.setBook(book);
item.setUser(user);
service.add(item);
return myCart(req, resp);
}

/**
* 我的购物车
* @param req
* @param resp
* @return
*/
public String myCart(HttpServletRequest req, HttpServletResponse resp) {
// 1. 得到uid
User user = (User)req.getSession().getAttribute("sessionUser");
String uid = user.getUid();

// 2. 通过service得到当前用户的所有购物车条目
List<CartItem> items = service.myCart(uid);

// 3. 保存起来，转发到/cart/list.jsp
req.setAttribute("items", items);
return "f:/jsps/cart/list.jsp";
}
}

3.service层

(1）CartItemService.java

public class CartItemService {

private CartItemDao dao = new CartItemDao();

/**
* 添加条目
* @param item
*/
public void add(CartItem item) {
try {
// 1. 使用uid和bid去数据库中查询这个条目是否存在
CartItem _item = dao.findByUidAndBid(item.getUser().getUid(), item.getBook().getBid());
if(_item == null){//如果原来没有这个条目，那么添加条目
item.setCartItemId(CommonUtils.uuid());
dao.add(item);
}else{//如果原来有这个条目，修改数量
// 使用原有数量和新条目数量之各，来做为新的数量
_item.setQuantity(_item.getQuantity() + item.getQuantity());
// 修改这个老条目的数量
dao.updateQuantity(_item);
}

} catch (SQLException e) {
throw new RuntimeException(e);
}
}

/**
* 我的购物车功能
* @param uid
* @return
*/
public List<CartItem> myCart(String uid) {
try {
return dao.findByUser(uid);
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
}

4.dao层

(1）CartItem.java

public class CartItemDao {
private QueryRunner qr = new TxQueryRunner();

/**
* 添加条目
* @param item
* @throws SQLException
*/
public void add(CartItem item) throws SQLException {
String sql = "insert into t_cartitem(cartItemId, quantity, bid, uid) values (?,?,?,?)";
Object [] params = {item.getCartItemId(), item.getQuantity(), item.getBook().getBid(), item.getUser().getUid()};
qr.update(sql, params);
}

/**
* 通过用户查询购物车条目
* @param uid
* @return
* @throws SQLException
*/
public List<CartItem> findByUser(String uid) throws SQLException {
String sql = "select * from t_cartitem c,t_book b where uid=? and c.bid=b.bid";
List<Map<String, Object>> mapList = qr.query(sql, new MapListHandler(), uid);
return toCartItemList(mapList);
}

/**
* 把多个Map(List<Map>)映射成多个CartItem(List<CartItem>)
* @param mapList
* @return
*/
private List<CartItem> toCartItemList(List<Map<String, Object>> mapList) {
List<CartItem> items = new ArrayList<CartItem>();
CartItem item = null;
for(Map<String, Object> map : mapList) {
item = toCartItem(map);
items.add(item);
}
item = null;
return items;
}

/**
* 把一个Map映射成一个Cartitem
* @param map
* @return
*/
private CartItem toCartItem(Map<String, Object> map) {
if(map == null || map.size() == 0) return null;
CartItem item = CommonUtils.toBean(map, CartItem.class);
User user = CommonUtils.toBean(map, User.class);
Book book = CommonUtils.toBean(map, Book.class);
item.setUser(user);
item.setBook(book);
return item;
}

/**
* 查询某个用户的某本图书的购物车条目是否存在
* @param uid
* @param bid
* @return
* @throws SQLException
*/
public CartItem findByUidAndBid(String uid, String bid) throws SQLException {
String sql= "SELECT * FROM t_cartitem c, t_user u, t_book b WHERE c.uid=u.uid AND c.bid=b.bid AND c.uid=? AND c.bid=?";
Map<String,Object> map = qr.query(sql, new MapHandler(), uid, bid);
return toCartItem(map);
}

/**
* 修改指定条目的数量
* @param _item
* @throws SQLException
*/
public void updateQuantity(CartItem _item) throws SQLException {
String sql = "update t_cartitem set quantity=? where cartItemId=?";
qr.update(sql, _item.getQuantity(), _item.getCartItemId());
}
}