（二十七）分类信息的curd-分类信息修改 

 
        
    修改分类步骤分析:
        1.在list.jsp页面上点击修改(编辑)
            /store/adminCategory?method=getById&cid=???
        2.在getById方法中
            获取cid
            调用service 通过id获取一个分类,
            将category放入request域中
            请求转发 edit.jsp
        3.eidt页面是一个表单
            添加action属性
                /store/adminCategory?method=update
            修改内容 点击提交
            添加隐藏域 cid
        4.在update方法中
            获取cid和cname
            封装成category
            调用service的update方法
            重定向/store/adminCategory?method=findAll
        5.在service的update方法中
            调用dao更新
            清空缓存
        6.dao中更新数据

/store/WebContent/admin/category/list.jsp

/store/src/com/louis/web/servlet/AdminCategoryServlet.java

 

/**
     * 通过id获取分类信息
     * @param request
     * @param response
     * @return
     * @throws Exception
     */
    public String getById(HttpServletRequest request, HttpServletResponse response) throws Exception {
        //1.接受cid
        String cid = request.getParameter("cid");
        
        //2 调用service完成 查询操作 返回值:category
        CategoryService cs=(CategoryService) BeanFactory.getBean("CategoryService");
        Category c=cs.getById(cid);
        
        //3.将category放入request域中, 请求转发  /admin/category/edit.jsp
        request.setAttribute("bean", c);
        return "/admin/category/edit.jsp";
    }

/store/src/com/louis/service/impl/CategoryServiceImpl.java

/*
     * 通过cid获取一个分类对象
     */
    @Override
    public Category getById(String cid) throws Exception {
        CategoryDao cd = (CategoryDao) BeanFactory.getBean("CategoryDao");
        return cd.getById(cid);
    }

/store/src/com/louis/dao/impl/CategoryDaoImpl.java

    /**
     * 通过id获取一个分类
     */
    @Override
    public Category getById(String cid) throws Exception {
        QueryRunner qr = new QueryRunner(DataSourceUtils.getDataSource());
        String sql="select * from category where cid = ? limit 1";
        return qr.query(sql, new BeanHandler<>(Category.class), cid);
    }

/store/WebContent/admin/category/edit.jsp

<%@ page language="java" pageEncoding="UTF-8"%>
<HTML>
    <HEAD>
        <meta http-equiv="Content-Language" content="zh-cn">
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <LINK href="${pageContext.request.contextPath}/css/Style1.css" type="text/css" rel="stylesheet">
    </HEAD>
    
    <body>
        <form id="userAction_save_do" name="Form1" action="${pageContext.request.contextPath}/adminCategory?method=update" method="post">
            <!-- 隐藏域 存放cid -->
            <input type="hidden" name="cid" value="${bean.cid }">
            &nbsp;
            <table cellSpacing="1" cellPadding="5" width="100%" align="center" bgColor="#eeeeee" style="border: 1px solid #8ba7e3" border="0">
                <tr>
                    <td class="ta_01" align="center" bgColor="#afd1f3" colSpan="4"
                        height="26">
                        <strong><STRONG>编辑分类</STRONG>
                        </strong>
                    </td>
                </tr>

                <tr>
                    <td width="18%" align="center" bgColor="#f5fafe" class="ta_01">
                        分类名称：
                    </td>
                    <td class="ta_01" bgColor="#ffffff" colspan="3">
                        <input type="text" name="cname" id="userAction_save_do_logonName" value="${bean.cname }" class="bg"/>
                    </td>
                </tr>
            
                <tr>
                    <td class="ta_01" style="WIDTH: 100%" align="center"
                        bgColor="#f5fafe" colSpan="4">
                        <button type="submit" id="userAction_save_do_submit" value="确定" class="button_ok">
                            &#30830;&#23450;
                        </button>

                        <FONT face="宋体">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT>
                        <button type="reset" value="重置" class="button_cancel">&#37325;&#32622;</button>

                        <FONT face="宋体">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT>
                        <INPUT class="button_ok" type="button" onclick="history.go(-1)" value="返回"/>
                        <span id="Label1"></span>
                    </td>
                </tr>
            </table>
        </form>
    </body>
</HTML>

/store/WebContent/admin/category/edit.jsp

 

/store/src/com/louis/web/servlet/AdminCategoryServlet.java

/**
     * 更新分类信息方法
     * @param request
     * @param response
     * @return
     * @throws Exception
     */
    public String update(HttpServletRequest request, HttpServletResponse response) throws Exception {
        //1.获取cid cname
        //2.封装参数
        Category c=new Category();
        c.setCid(request.getParameter("cid"));
        c.setCname(request.getParameter("cname"));
        
        //3.调用service 完成更新操作
        CategoryService cs=(CategoryService) BeanFactory.getBean("CategoryService");
        cs.update(c);
        
        //4.重定向 查询所有
        response.sendRedirect(request.getContextPath()+"/adminCategory?method=findAll");
        
        return null;
    }

/store/src/com/louis/service/impl/CategoryServiceImpl.java

/**
     * 更新分类
     */
    @Override
    public void update(Category c) throws Exception {
        //1.调用dao更新
        CategoryDao cd = (CategoryDao) BeanFactory.getBean("CategoryDao");
        cd.update(c);
        
        //2.清空缓存
        CacheManager cm = CacheManager.create(CategoryServiceImpl.class.getClassLoader().getResourceAsStream("ehcache.xml"));
        Cache cache = cm.getCache("categoryCache");
        cache.remove("clist");
    }

/store/src/com/louis/dao/impl/CategoryDaoImpl.java

/**
     * 更新
     */
    @Override
    public void update(Category c) throws Exception {
        QueryRunner qr = new QueryRunner(DataSourceUtils.getDataSource());
        String sql="update category set cname = ? where cid = ?";
        qr.update(sql, c.getCname(),c.getCid());
    }

 

问题

1、为什么要使用隐藏域

答：因为是cid

posted on 2017-10-16 10:51  Michael2397  阅读(337)  评论(0)  编辑  收藏  举报

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