其實現和擷取所有的商品是非常相似的。這裡還用到了一個PreparedStatment的一個可以傳參的屬性。
public Book getBookByISBN(String isbn){ Connection conn = null; PreparedStatement preStmt = null; ResultSet bookSet = null; try{//--------------- 1. 串連資料庫------------------ conn = DBHelper.getConnection();//--------------- 2. 執行SQL語句，接收執行結果集ResultSet ------------------ String sql = "select * from book where isbn=?;"; preStmt = conn.prepareStatement(sql); preStmt.setString(1, isbn); bookSet = preStmt.executeQuery();//--------------- 3. 處理執行結果集ResultSet ------------------ if(bookSet.next()){ Book book = new Book(); book.setAuthor(bookSet.getString("author")); book.setImg(bookSet.getString("img")); book.setIntro(bookSet.getString("intro")); book.setIsbn(bookSet.getString("isbn")); book.setName(bookSet.getString("name")); book.setPrice(Float.parseFloat(bookSet.getString("price"))); book.setPrice_original(Float.parseFloat(bookSet.getString("price_original"))); book.setPublish_company(bookSet.getString("publish_company"));// 時間格式化 SimpleDateFormat dateformat = new SimpleDateFormat( "yyyy年MM月dd日 "); ParsePosition pos = new ParsePosition(0); book.setPublish_time(dateformat.parse(bookSet.getString("name"),pos)); return book; }else{ return null; } }catch(Exception ex){ ex.printStackTrace(); return null; }finally{//--------------- 4. 必要的關閉ResultSet、Statement ------------------// 為了確保資源不被佔用，需要在fianlly釋放資源，注意這裡不可以關閉Connection，否則會報錯// 釋放 ResultSet if(bookSet != null){ try{ bookSet.close(); bookSet = null; }catch(Exception ex){ ex.printStackTrace(); } }// 釋放語句對象：PreparedStatement if(preStmt != null){ try{ preStmt.close(); preStmt = null; }catch(Exception ex){ ex.printStackTrace(); } } }}
顯示單一商品詳細頁
我們不難發現，index.jsp頁和single頁的頭部和尾部是一樣的，因此我們可以用JSP的3個編譯指令（page、include和taglib）中的include指令來最佳化代碼。
使用include指令，可以將一個外部檔案嵌入到當前JSP檔案中，同時解析這個頁面中的JSP語句。文法如下：
<%@ include file="檔案相對路徑" %>
所以，下面我們建立兩個檔案：header.jsp和footer.jsp分別存放網頁的頭部和尾部代碼。然後single.jsp代碼如下。同時用同樣的方法修改index.jsp檔案。
header.jsp
<%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE html><html lang="en"><head> <base href="<%=basePath%>"> <meta charset="UTF-8"> <title>DIAGRAM</title> <link rel="shortcut icon" type="image/x-icon" href="favicon.ico" /> <link href="./bootstrap-3.3.0/css/bootstrap.min.css" rel="stylesheet"/> <link href="./css/style.css" rel="stylesheet"/> <link href="./css/single.css" rel="stylesheet"/></head><body> <nav class="navbar navbar-default" role="navigation"> <div class="logo-big"><span>D I A G R A M</span></div> <div class="container-fluid"> <div class="row nav-menuare"> <div class="navbar-header"> <a class="navbar-brand logo-small" href="#">DIAGRAM</a> <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false"> <span class="sr-only">Toggle navigation</span> <span class="icon-bar"></span> <span class="icon-bar"></span> <span class="icon-bar"></span> </button> </div> <div class="row navbar-row"> <div class="nav-divider col-md-3 col-sm-3"><span class="divider"></span></div> <div id="navbar" class="col-md-6 col-sm-6 collapse"> <ul> <li class="li-col"><a href="#">SHOPINDEX</a></li> <li class="li-col"><a href="#">NEWBOOK</a></li> <li class="li-col li-logo"><a href="./index.jsp"><img class="logo-img" src="./img/robot.png"/></a></li> <li class="li-col"><a href="#">CART(2)</a></li> <li class="li-col"><a href="#">CUSTOMER</a></li> </ul> </div> <div class="nav-divider col-md-3 col-sm-3"><span class="divider"></span></div> </div> </div> </div> </nav>
footer.jsp
<div class="footer"> <div class="container-fluid"> <div class="row"> <div class="col-md-3"> </div> <div class="blog-coyp col-md-6"> <div class="blog text-left"><a href="https://github.com/donespeak" target="_blank">GITHUB</a> | <a href="http://blog.csdn.net/donespeak" target="_blank">CSDN</a> | EMAIL:yangguanr@gmail.com </div><div class="copy text-right">©DoneSpeak.inc</div> </div> </div> </div> </div> <script src="./js/jquery-2.1.4.min.js"></script> <script src="./bootstrap-3.3.0/js/bootstrap.min.js"></script> <script src="./js/script.js"></script></body></html>
single.jsp
<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%><%@ page import="entity.Book" %><%@ page import="dao.BookDAO" %><%@ include file="header.jsp" %> <div class="main newbook-all"> <div class="container-fluid"> <div class="row"> <% BookDAO bookdao = new BookDAO(); Book book = bookdao.getBookByISBN(request.getParameter("isbn")); if(book != null){ %> <div class="col-md-3 col-md-offset-1 col-sm-4 col-sm-offset-1"> <div class="book-img"> <img src="img/<%= book.getImg() %>" /> </div> </div> <div class="sell col-md-5 col-sm-6"> <div class="booktext"> <h3>《<%= book.getName() %>》</h3> <div class="divider divider-bookinfo"></div> <p><span class="t1">作者:<%= book.getAuthor() %></span><span class="t1">著出版社:<%= book.getPublish_company() %></span><span class="t1">出版時間:<%= book.getPublish_time() %></span><p> <p class="newbook-intro">《<%= book.getIntro() %></p> </div> <div class="snapped-up-btn-area"> <span class="cost">￥<%= book.getPrice() %></span> / <span class="cost-original">¥<%= book.getPrice_original() %></span><button class="snapup">Add To Cart</button> </div> </div> <% } %> <div class="col-md-2 record"> <div class="rec-head">瀏覽記錄</div> <div class="rec-card"> <a href="single.html"><img class="img-rec pull-left" src="img/圖解網站分析.jpg"/></a> <div class="pull-left txt-rec">圖解網站分析<br />￥34.8</div> </div> <div class="rec-card"> <a href="single.html"><img class="img-rec pull-left" src="img/圖解網站分析.jpg"/></a> <div class="pull-left txt-rec">圖解網站分析<br />￥34.8</div> </div> <div class="rec-card"> <a href="single.html"><img class="img-rec pull-left" src="img/圖解網站分析.jpg"/></a> <div class="pull-left txt-rec">圖解網站分析<br />￥34.8</div> </div> <div class="rec-card"> <a href="single.html"><img class="img-rec pull-left" src="img/圖解網站分析.jpg"/></a> <div class="pull-left txt-rec">圖解網站分析<br />￥34.8</div> </div> </div> </div> </div> </div><%@ include file="footer.jsp" %>
include指令
以上使用include的方式屬於靜態include指令，該指令會之間將指定檔案中的內容嵌入到指令所在位置中，在進行編譯。如果被內嵌檔案需要經常改變，建議使用操作指令。
是動作指令，其與上面的<%@include %>編譯指令有很大不同，它不是將檔案的內容直接嵌入，而是獨立運行完之後，將產生的輸出結果（html）嵌入，所以裡面的java代碼是不會被匯入的。事實上，用指定的檔案會獨立的產生一個Servlet，而<%@ include%>不會。基本文法格式如下：
<jsp:include page="{relativeURL | <%=expression%>}" flush="true"/><%-- 或者 --%><jsp:include page="{relativeURL | <%=expressiStart building with 50+ products and up to 12 months usage for Elastic Compute Service
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