CShop Project 06: 创建表对应的数据模型类 & Service和Dao层的商品查询方法

一. 　　创建表对应的数据模型类

在com.Jasper2003.model 包下, 添加数据模型:

1.　　Goods.java

 

 2.　　Type.java

 3.　　Recommend.java

二. 　　创建Service和Dao层的热销商品查询方法

<1> Dao层 - 获取数据

public class GoodsDao {
    
    public List<Map<String, Object>> getHotGoodsList() throws SQLException {
        QueryRunner r = new QueryRunner(DBUtil.getDataSource());
        String sql = "select g.id,g.name,g.cover,g.price,t.name typename from recommend r,goods g,type t where type=2 and r.goods_id=g.id and g.type_id=t.id";
        return r.query(sql,new MapListHandler());
    }
}

<2> Service层 - 调用Dao层的查询方法 (由于逻辑比较简单,　故直接调用Ｄao层的方法)

public class GoodsService {

    private GoodsDao gDao = new GoodsDao();

    public List<Map<String, Object>> getHotGoodsList() {
        List<Map<String, Object>> list = null;
        try {
            list = gDao.getHotGoodsList();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return list;
    }
}

三.　　在Servlet调用Service

在IndexServlet.java中:

protected void doGet() {

        // 取得热销商品
        List<Map<String, Object>> list = gService.getHotGoodsList();
        request.setAttribute("hotList", list);
}

四.　　在页面端取得数据,　并展示在页面上

在index.jsp中:

<div class="alert alert-danger">热销推荐</div>
            <div class="gallery-grids">
                <c:forEach items="${hotList}" var="g">
                    <div class="col-md-4 gallery-grid glry-two">
                        <a href="detail.action?goodid=6">
                            <img src="${pageContext.request.contextPath }${g.cover}" class="img-responsive" alt="${g.name}" width="350" height="350"/>
                        </a>
                        <div class="gallery-info galrr-info-two">
                            <p>
                                <span class="glyphicon glyphicon-eye-open" aria-hidden="true"></span>
                                <a href="detail.action?goodid=6">查看详情</a>
                            </p>
                            <a class="shop" href="javascript:;" onclick="buy(6)">立刻购买</a>
                            <div class="clearfix"> </div>
                        </div>
                        <div class="galy-info">
                            <p>${g.typeName } > ${g.name }</p>
                            <div class="galry">
                                <div class="prices">
                                    <h5 class="item_price">¥ ${g.price }</h5>
                                </div>
                                <div class="clearfix"></div>
                            </div>
                        </div>
                    </div>            
                </c:forEach>                
            </div>        

效果 （http://localhost:8080/web06_cakeshop/）

 此时, 热销商品是"动态"的,随着数据库的改动而改动