一、流程分析
1.分类管理介绍
2.查询所有分类
二、代码
1.view层
(1）top.jsp
1 <body style="background: rgb(78,78,78);color: #fff;"> 2 <h1 style="text-align: center; line-height: 30px;">网上书城系统后台管理</h1> 3 <div style="line-height: 10px;"> 4 <span>管理员：${sessionScope.admin.adminname }</span> 5 <a target="_top" href="<c:url value='/adminjsps/login.jsp'/>">退出</a> 6 <span style="padding-left:50px;"> 7 <a href="<c:url value='/admin/AdminCategoryServlet?method=findAll'/>">分类管理</a> 8 <a href="<c:url value='/adminjsps/admin/book/main.jsp'/>">图书管理</a> 9 <a href="<c:url value='/admin/AdminOrderServlet?method=findAll'/>">订单管理</a> 10 </span> 11 </div> 12 </body>
(2)list.jsp
1 <body> 2 <h2 style="text-align: center;">分类列表</h2> 3 <table align="center" border="1" cellpadding="0" cellspacing="0"> 4 <caption class="captionAddOneLevel"> 5 <a href="<c:url value='/adminjsps/admin/category/add.jsp'/>">添加一级分类</a> 6 </caption> 7 <tr class="trTitle"> 8 <th>分类名称</th> 9 <th>描述</th> 10 <th>操作</th> 11 </tr> 12 13 <c:forEach items="${parents }" var="parent"> 14 <tr class="trOneLevel"> 15 <td width="200px;">${parent.cname }</td> 16 <td>${parent.desc }</td> 17 <td width="200px;"> 18 <a href="<c:url value='/admin/AdminCategoryServlet?method=addChildPre&pid=${parent.cid }'/>">添加二级分类</a> 19 <a href="<c:url value='/admin/AdminCategoryServlet?method=editParentPre&cid=${parent.cid }'/>">修改</a> 20 <a onclick="return confirm('您是否真要删除该一级分类？')" href="<c:url value='/admin/AdminCategoryServlet?method=deleteParent&cid=${parent.cid }'/>">删除</a> 21 </td> 22 </tr> 23 <c:forEach items="${parent.children }" var="child"> 24 <tr class="trTwoLevel"> 25 <td>${child.cname }</td> 26 <td>J${child.desc }</td> 27 <td width="200px;" align="right"> 28 <a href="<c:url value='/admin/AdminCategoryServlet?method=editChildPre&cid=${child.cid }'/>">修改</a> 29 <a onclick="return confirm('您是否真要删除该二级分类？')" href="<c:url value='/admin/AdminCategoryServlet?method=deleteChild&cid=${child.cid }'/>">删除</a> 30 </td> 31 </tr> 32 </c:forEach> 33 </c:forEach> 34 35 </table> 36 </body>
2.servlet层
(1）AdminCategoryServlet.java
1 /** 2 * 查询所有分类 3 * @param req 4 * @param resp 5 * @return 6 * @throws ServletException 7 * @throws IOException 8 */ 9 public String findAll(HttpServletRequest req, HttpServletResponse resp) 10 throws ServletException, IOException { 11 List<Category> parents = service.findAll(); 12 req.setAttribute("parents", parents); 13 return "/adminjsps/admin/category/list.jsp"; 14 }
3.service层
(1）CategoryService.java
1 /** 2 * 查询所有分类 3 * @return 4 */ 5 public List<Category> findAll() { 6 try { 7 return categoryDao.findAll(); 8 } catch (SQLException e) { 9 throw new RuntimeException(e); 10 } 11 }
4.dao层
(1）CategoryDao.java
1 /** 2 * 返回所有分类 3 * @return 4 * @throws SQLException 5 */ 6 public List<Category> findAll() throws SQLException { 7 // 1. 查询出所有一级分类 8 String sql = "SELECT * FROM t_category WHERE pid IS NULL ORDER BY orderBy"; 9 List<Map<String,Object>> mapList = qr.query(sql, new MapListHandler()); 10 11 List<Category> parents = toCategoryList(mapList); 12 13 // 2. 循环遍历所有的一级分类，为每个一级分类加载它的二级分类 14 for(Category parent : parents) { 15 // 查询出当前父分类的所有子分类 16 List<Category> children = findByparent(parent.getCid()); 17 // 设置给父分类 18 parent.setChildren(children); 19 } 20 return parents; 21 } 22 23 /** 24 * 可以把多个Map(List<Map>)映射成多个Category(List<Category>) 25 * @param mapList 26 * @return 27 */ 28 private List<Category> toCategoryList(List<Map<String, Object>> mapList) { 29 List<Category> categoryList = new ArrayList<Category>(); 30 for(Map<String,Object> map : mapList) { 31 Category c = toCategory(map); 32 categoryList.add(c); 33 } 34 return categoryList; 35 } 36 37 38 /** 39 * 把一个Map中的数据映射到Category中 40 * @param map 41 * @return 42 */ 43 private Category toCategory(Map<String, Object> map) { 44 /* 45 * map {cid:xx, cname:xx, pid:xx, desc:xx, orderBy:xx} 46 * Category{cid:xx, cname:xx, parent:(cid=pid), desc:xx} 47 */ 48 Category category = CommonUtils.toBean(map, Category.class); 49 String pid = (String) map.get("pid"); 50 if(pid != null) { 51 Category parent = new Category(); 52 parent.setCid(pid); 53 category.setParent(parent); 54 } 55 return category; 56 } 57 58 /** 59 * 通过父分类查询子分类 60 * @param cid 61 * @return 62 * @throws SQLException 63 */ 64 public List<Category> findByparent(String cid) throws SQLException { 65 String sql = "select * from t_category where pid=?"; 66 List<Map<String,Object>> mapList = qr.query(sql, new MapListHandler(), cid); 67 return toCategoryList(mapList); 68 }