2.6

今天主要是对多条件查询进行巩固，因为模糊查询主要就是运用like和符号，而多条件查询则分为并和或，则是需要利用if语句来进行区别

 这里主要是放Dao层和Servlet

   public List<Book> search(Integer id, String name, Double maxPrice, Double minPrice,
                                 String category, Integer maxPnum, Integer minPnum, String imgurl,
                                 String description, String author, Integer maxSales,Integer minSales) {
            return bookDao.search(id, name, maxPrice, minPrice, category, maxPnum, minPnum, imgurl,
                    description, author, maxSales, minSales);
        }



   //复杂条件查询
        public List<Book> search(Integer id, String name, Double maxPrice, Double minPrice,
                                 String category, Integer maxPnum, Integer minPnum, String imgurl,
                                 String description, String author, Integer maxSales,Integer minSales){
     
            //这个是用于存储查询的结果的
            List<Book> books = new ArrayList<Book>();
            //这个用于存储查询的条件参数的
            List list = new ArrayList();
     
            Connection conn = null;
            PreparedStatement pstmt = null;
            ResultSet rs = null;
     
            try {
     
                //创建资源链接对象
                conn = getConnection();
                //定义sql语句
                String sql = "select * from book where 1 = 1";
     
                //书本编号不为空的时候
                if (id != 0) {
                    sql = sql + " and id = ?";
                    list.add(id);
                }
     
                //去除掉姓名的空白位置
                if (!"".equals(name.trim())){
                    sql = sql + " and name like ?";
                    list.add("%" + name.trim() + "%");
                }
     
                //最高价格
                if (maxPrice != 0.0) {
                    sql = sql + " and price < ?";
                    list.add(maxPrice);
                }
     
                //最低价格
                if (minPrice != 0.0) {
                    sql = sql + " and price > ?";
                    list.add(minPrice);
                }
     
                //如果类别名不为空
                if (!"".equals(category.trim())) {
                    sql = sql + " and category like ?";
                    list.add("%" + category.trim() + "%");
                }
     
                //最大库存
                if (maxPnum != 0) {
                    sql = sql + " and pnum < ?";
                    list.add(maxPnum);
                }
     
                //最小库存
                if (minPnum != 0) {
                    sql = sql + " and pnum > ?";
                    list.add(minPnum);
                }
     
                //作品封面
                if (!"".equals(imgurl.trim())) {
                    sql = sql + "and imgurl like ?";
                    list.add("%" + imgurl.trim() + "%");
                }
     
                //作品描述
                if (!"".equals(description.trim())){
                    sql = sql + " and description like ?";
                    list.add("%" + description.trim() + "%");
                }
     
                //作者
                if (!"".equals(author.trim())){
                    sql = sql + " and author like ?";
                    list.add("%" + author.trim() + "%");
                }
     
                //最大销量
                if (maxSales != 0){
                    sql = sql + " and sales < ?";
                    list.add(maxSales);
                }
     
                //最低销量
                if (minSales != 0){
                    sql = sql + " and sales > ?";
                    list.add(minSales);
                }
     
                //创建sql执行对象
                pstmt = conn.prepareStatement(sql);
     
                //给?参数进行赋值
                if (list.size() > 0) {
                    for (int i = 0; i < list.size(); i++) {
                        pstmt.setObject(i+1,list.get(i));
                    }
                }
     
                //执行sql
                rs = pstmt.executeQuery();
                //遍历查询
                while (rs.next()){
     
                    Book book = new Book();
     
                    book.setId(rs.getInt("id"));
                    book.setName(rs.getString("name"));
                    book.setPrice(rs.getDouble("price"));
                    book.setCategory(rs.getString("category"));
                    book.setPnum(rs.getInt("pnum"));
                    book.setImgurl(rs.getString("imgurl"));
                    book.setDescription(rs.getString("description"));
                    book.setAuthor(rs.getString("author"));
                    book.setSales(rs.getInt("sales"));
     
                    books.add(book);
                }
     
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                //关闭资源链接对象
                close(rs,pstmt,conn);
            }
            //返回一个带有参数的list集合
            return books;
        }

jsp页面

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <meta charset="UTF-8">
    <title>国际图书商城</title>
 
    <link rel="stylesheet" href="static/bootstrap/css/bootstrap.min.css"/>
    <script src="static/bootstrap/js/jquery-3.1.0.min.js"></script>
    <script src="static/bootstrap/js/bootstrap.min.js"></script>
 
    <style>
        table {
            border: 3px solid;
            margin: auto;
            width: 900px;
            text-align: center;
        }
 
        h3 {
            text-align: center;
        }
    </style>
 
</head>
<body>
    <h3>国际图书商城</h3>
 
    <h3>多条件动态查询</h3>
    <form action="searchServlet" method="post">
        <table>
            <tr>
                <td>
                    编号:
                </td>
 
                <td>
                    <input type="text" name="id">
                </td>
            </tr>
 
            <tr>
                <td>
                    书名:
                </td>
 
                <td>
                    <input type="text" name="name">
                </td>
            </tr>
 
            <tr>
                <td>
                    最高价格:
                </td>
 
                <td>
                    <input type="text" name="maxPrice">
                </td>
            </tr>
 
            <tr>
                <td>
                    最低价格:
                </td>
 
                <td>
                    <input type="text" name="minPrice">
                </td>
            </tr>
 
            <tr>
                <td>
                    类别:
                </td>
 
                <td>
                    <input type="text" name="category">
                </td>
            </tr>
 
            <tr>
                <td>
                    最大库存:
                </td>
 
                <td>
                    <input type="text" name="maxPnum">
                </td>
            </tr>
 
            <tr>
                <td>
                    最小库存:
                </td>
 
                <td>
                    <input type="text" name="minPnum">
                </td>
            </tr>
 
            <tr>
                <td>
                    封面:
                </td>
 
                <td>
                    <input type="text" name="imgurl">
                </td>
            </tr>
 
            <tr>
                <td>
                    描述:
                </td>
 
                <td>
                    <input type="text" name="description">
                </td>
            </tr>
 
            <tr>
                <td>
                    作者:
                </td>
 
                <td>
                    <input type="text" name="author">
                </td>
            </tr>
 
            <tr>
                <td>
                    最高售量:
                </td>
 
                <td>
                    <input type="text" name="maxSales">
                </td>
            </tr>
 
            <tr>
                <td>
                    最低售量:
                </td>
 
                <td>
                    <input type="text" name="minSales">
                </td>
            </tr>
 
        </table>
 
        <center><input type="submit" value="查询"></center>
    </form>
 
<table border="1" cellspacing="0">
    <tr>
        <th>编号</th>
        <th>书名</th>
        <th>价格</th>
        <th>类别</th>
        <th>库存</th>
        <th>封面</th>
        <th>描述</th>
        <th>作者</th>
        <th>售量</th>
        <th></th>
        <th></th>
        <th></th>
        <th></th>
 
    </tr>
 
    <%--
        使用foreach循环进行遍历输出
        我们重新来理解一下foreach:
            当我们在requestScope中传入一个books集合的时候，
            我们的foreach容器就多了一个books集合,对其进行遍历也就是遍历books容器里面的每一个book对象
            这样的话我们每一个book对象就可以通过"."的方式,把具体的属性值取出来,这里类似于mybatis
    --%>
    <%--
        用于分页的：
        <c:forEach items="${pageBean.books}" var="book" varStatus="vs">
    --%>
 
    <%--正常使用的/复杂查询使用的--%>
    <c:forEach items="${books}" var="book" varStatus="vs">
        <tr>
            <td>${vs.count}</td>
            <td>${book.name}</td>
            <td>${book.price}</td>
            <td>${book.category}</td>
            <td>${book.pnum}</td>
            <td>${book.imgurl}</td>
            <td>${book.description}</td>
            <td>${book.author}</td>
            <td>${book.sales}</td>
            <td>
                    <%--这里在路径上传了一个book的id=book.id过去给后台--%>
                <a href="deleteBooksServlet?id=${book.id}">删除</a>
            </td>
 
            <td>
                <a href="selectByIdServlet?id=${book.id}">更新</a>
            </td>
 
            <td>
                <a href="addCartServlet?id=${book.id}">添加到购物车</a>
            </td>
 
            <td>
                <a href="addDataServlet?id=${book.id}">查看详情</a>
            </td>
        </tr>
    </c:forEach>
 
</table>
 
<br>
<br>
<br>
<center><b>请选择操作：</b></center>
<br>
<table>
    <tr>
        <td>
            <a href="addBook.jsp">新增图书</a>
        </td>
    </tr>
 
    <tr>
        <td>
            <a href="index.jsp">返回首页</a>
        </td>
    </tr>
 
    <tr>
        <td>
            <a href="showCartServlet">查看购物车</a>
        </td>
    </tr>
 
    <tr>
        <td>
            <a href="showDataServlet">查看浏览记录</a>
        </td>
    </tr>
</table>
 
<nav aria-label="Page navigation">
    <ul class="pagination">
        <c:if test="${pageBean.currentPage==1}">
            <li class="disabled">
        </c:if>
 
        <c:if test="${pageBean.currentPage!=1}">
            <li>
        </c:if>
 
            <a href="pageServlet?currentPage=${pageBean.currentPage==1?1:pageBean.currentPage-1}" >
                <span aria-hidden="true">
                    &laquo;
                </span>
            </a>
        </li>
 
        <c:forEach begin="1" end="${pageBean.totalPage}" var="i">
            <c:if test="${pageBean.currentPage == i}">
                <li class="active"><a href="pageServlet?currentPage=${i}">${i}</a></li>
            </c:if>
 
            <c:if test="${pageBean.currentPage!=i }">
                <li><a href="pageServlet?currentPage=${i}">${i}</a></li>
            </c:if>
        </c:forEach>
 
        <c:if test="${pageBean.currentPage==pageBean.totalPage}">
            <li class="disabled">
        </c:if>
 
        <c:if test="${pageBean.currentPage!=pageBean.totalPage}">
            <li>
        </c:if>
 
            <a href="pageServlet?currentPage=${pageBean.currentPage == pageBean.totalPage?pageBean.totalPage:pageBean.currentPage+1}">
                <span aria-hidden="true">
                    &raquo;
                </span>
            </a>
        </li>
    </ul>
</nav>
    <span style="font-size:15px;margin-left:5px;">
        共${pageBean.count}条记录,共${pageBean.totalPage}页
    </span>
</div>
 
<%--<div class="page">--%>
 
<%--<a href="pageServlet?currentPage=${pageBean.currentPage==1?1:pageBean.currentPage-1}">--%>
<%--&it;&it;上一页--%>
<%--</a>&nbsp;&nbsp;--%>
 
<%--第${pageBean.currentPage}页/共${pageBean.totalPage}页&nbsp;&nbsp;--%>
 
<%--<a href="pageServlet?currentPage=${pageBean.currentPage == pageBean.totalPage?pageBean.totalPage:pageBean.currentPage+1}">--%>
<%--下一页&gt;&gt;--%>
<%--</a>--%>
 
<%--</div>--%>
 
</body>
</html>