javaWeb核心技术第十二篇之分页和条件
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互联网集市收集整理的这篇技术教程文章主要介绍了javaWeb核心技术第十二篇之分页和条件，小编现在分享给大家，供广大互联网技能从业者学习和参考。文章包含26559字，纯文字阅读大概需要38分钟。
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分页:limit ?,? 参数1 : startIndex 开始索引. 参数2 : pageSize 每页显示的个数 n 表示第几页 给定一个特殊的单词 pageNumber select * from product; 第一页显示五条数据: select * from product LIMIT 0 , 5; 第二页显示五条数据 select * from product LIMIT 5 , 5; 第三页显示五条数据 select * from product LIMIT 10 , 5; 第N页显示五条数据 select * from product LIMIT (pageNumber-1)*pageSize , pageSize; 如果只有一个参数 表示 第一页 显示几个数据 select * from product LIMIT 5; 简单分页查询步骤: 1.sql : select from table limit ?,? 2.startIntdex : 开始索引 不可以是负数 3.pageSize : 每页显示的个数 4.pageNumber : 用户访问的当前页 5.由页面发起传入 pageNumber 和 pageSize(目前写死) 在service层中进行计算startIndex 6.公式 (pageNumber-1)*pageSize 高级分页查询: 将service返回的六个参数,封装成一个PageBean 两个传的 pageNumber,pageSize. 两个查的 totalRecord,data 两个算的 startIndex,totalPage 在service编写代码逻辑 --> 将所有的代码逻辑封装到PageBean中 /* <!--分页 class="disabled" class="active"--> <div style="width:1100px;margin:0 auto;margin-top:50px;"> <ul class="pagination" style="text-align:center; margin-top:10px;"> <%-- 如果当前页 等于 1 不需要再显示上一页 如果当前不等于1 显示 --%> <c:if test="${pageBean.pageNumber != 1}"> <li ><a href="${pageContext.request.contextPath}/ProductServlet?method=findAll&pageNumber=1" aria-label="Previous"><span aria-hidden="true">«</span></a></li> <li ><a href="${pageContext.request.contextPath}/ProductServlet?method=findAll&pageNumber=${pageBean.pageNumber - 1 }" aria-label="Previous"><span aria-hidden="true">上一页</span></a></li> </c:if> <%-- 循环显示 所有的页数 --%> <c:forEach begin="${pageBean.start}" end="${pageBean.end}" var="num" step="1"> <li ${pageBean.pageNumber == num ? " class=‘active‘" : ""} ><a href="${pageContext.request.contextPath}/ProductServlet?method=findAll&pageNumber=${num}">${num}</a></li> </c:forEach> <%-- 如果当前页小于总页数 显示下一页 --%> <c:if test="${pageBean.pageNumber < pageBean.totalPage}"> <li><a href="${pageContext.request.contextPath}/ProductServlet?method=findAll&pageNumber=${pageBean.pageNumber + 1 }" aria-label="Next"><span aria-hidden="true">下一页</span></a></li> <li><a href="${pageContext.request.contextPath}/ProductServlet?method=findAll&pageNumber=${pageBean.totalPage}" aria-label="Next"><span aria-hidden="true">»</span></a></li> </c:if> </ul> </div> <!-- 分页结束======================= --> 以后专门用来处理分页的数据: 泛型的定义: 1:方法级别的定义,修饰和返回值之间<T> 2:类级别泛型定义,类名后<T> public class PageBean<T> { /* 一共六个参数: 2个传入: pageNumber : 表示当前页 pageSize : 表示每页显示个数 2个查询 data : 分页的数据 totalRecord : 总记录数 2个计算 startIndex : 开始索引 totalPage : 总页数 private int pageNumber; private int pageSize; private int totalRecodr; private int startIndex; private int totalPage; private List<T> data; public int getStartIndex() { startIndex = (pageNumber - 1)*pageSize; } public int getTotalPage() { if(totalRecord % pageSize == 0) { totalPage = totalRecord / pageSize; }else { totalPage = totalRecord / pageSize + 1; } return totalPage; } public int getPageNumber() { return pageNumber; } public void setPageNumber(int pageNumber) { this.pageNumber = pageNumber; } } 开发中真实案例--前五后四动态条 - 扩展 - 前四后五 开发中应用: //循环的开始 private int start; //循环结束 private int end; //计算 开始 和 结束的数据 private void jisuan() { //总页数有没有可能小于10 //小于 10 不需要前四后五的动态条 if(getTotalPage() < 10) {//必须调用getTotalPage() 因为totalPage需要提前计算 start = 1; end = totalPage;//最后一页等于最大页数 }else { //总页数一定大于10 需要前四后五动态条 start = pageNumber - 4; end = pageNumber + 5; //如果start < 1 表示 当前1 2 3 4 总共显示10页 if(start < 1) { start = 1; end = 10; } //如果end > totalPage 需要 计算start值 if(end > totalPage) { end = totalPage; start = totalPage - 9; } } } 案例:代码体现 public class ProductServlet extends HttpServlet { protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { try { //获得页面传递的参数 用来执行某段代码 String method = request.getParameter("method"); ProductService pService = new ProductService(); CategoryService cService = new CategoryService(); //根据页面功能执行某段特殊的代码 if("findAll".equals(method)){ /** * 1.类型问题 两种解决方式: 1.正则 2.try * 2.索引不可以是负数 *///1.获得 // 获得分页的数据 pageNumber String pageNumberStr = request.getParameter("pageNumber"); int pageNumber = 1; try { //如果是a 强转失败 赋值操作没有成功 pageNumber = 1 pageNumber = Integer.valueOf(pageNumberStr); if(pageNumber < 1 ){ pageNumber = 1; } } catch (Exception e) { } int pageSize = 2; //2.处理 //List<Product> pList = pService.findByPage(pageNumber , pageSize); PageBean<Product> pageBean = pService.findByPage(pageNumber , pageSize); //3.响应 //3.1 将数据存到request request.setAttribute("pageBean", pageBean); //3.2 请求转发给jsp request.getRequestDispatcher("/admin/product/product_list.jsp").forward(request, response); return; } //添加商品前查询分类的数据if("addProductUI".equals(method)){ //1.获得 //2.处理 //2.1 调用service 查询出所有分类 返回值 List<Category> List<Category> cList = cService.findAll(); //3.响应 //3.1 将数据存到request request.setAttribute("cList", cList); //3.2 请求转发给product_add.jsp request.getRequestDispatcher("/admin/product/product_add.jsp").forward(request, response); return; } //添加商品数据if("addProduct".equals(method)){ //1.获得 //1.1 获得map Map<String, String[]> map = request.getParameterMap(); //1.2 创建Product Product product = new Product(); //1.3 封装数据 BeanUtils.populate(product, map); //1.4 手动封装数据 product.setPid( UUID.randomUUID().toString().replace("-", "") );//主键会随机生成 product.setPimage("products/1/c_0001.jpg"); product.setPdate(new Date().toLocaleString()); product.setIs_hot(0);//0表示非热门 product.setPflag(0);//0表示未下架 //2.处理 //调用service保存 pService.save(product); //3.响应 //重定向到查询所有的案例 response.sendRedirect(request.getContextPath() +"/ProductServlet?method=findAll"); return; } //根据pid查询出商品的信息if("findByPid".equals(method)){ //1.获得 //获得pid的编号 String pid = request.getParameter("pid"); //2 处理 //2.1 商品数据 Product product = pService.findByPid(pid); //2.2 分类的数据 List<Category> cList = cService.findAll(); //3 响应 request.setAttribute("product", product); request.setAttribute("cList", cList); request.getRequestDispatcher("/admin/product/product_edit.jsp").forward(request, response); return; } //修改商品数据的代码if("editProduct".equals(method)){ //1.获得 //1.1 获得map集合 Map<String, String[]> map = request.getParameterMap(); //1.2 创建product对象 Product product = new Product(); //1.3 封装 BeanUtils.populate(product, map); //2.处理 //2.1 调用service修改boolean flag = pService.update(product); //3.响应 //3.1 重定向到查询所有的案例if(flag){ //成功 response.sendRedirect(request.getContextPath() + "/ProductServlet?method=findAll"); } return ; } //根据pid删除商品if("deleteByPid".equals(method)){ //1.获得 //获得pid String pid = request.getParameter("pid"); //2.处理int count = pService.deleteByPid(pid); //3.响应if(count > 0){ response.sendRedirect(request.getContextPath() + "/ProductServlet?method=findAll"); } return; } } catch (Exception e) { e.printStackTrace(); } } protectedvoid doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub doGet(request, response); } publicstaticvoid main(String[] args) { System.out.println(UUID.randomUUID().toString().replace("-", "")); } } publicclass ProductService { /*public PageBean<Product> findByPage(int pageNumber, int pageSize) throws SQLException { //创建一个即将被返回的对象 PageBean<Product> PageBean<Product> pageBean = new PageBean<Product>(); ProductDao dao = new ProductDao(); //将pageNumber 转换成startIndex int startIndex = (pageNumber - 1) * pageSize; //查询当前页的2条数据 List<Product> data = dao.findByPage( startIndex, pageSize); //查询总记录数 int totalRecord = dao.findRecord(); //计算总页数 int totalPage = 0; if(totalRecord % pageSize == 0 ){ totalPage = totalRecord / pageSize; }else{ totalPage = totalRecord / pageSize + 1; } //赋值 pageBean.setData(data); pageBean.setPageNumber(pageNumber); pageBean.setPageSize(pageSize); pageBean.setStartIndex(startIndex); pageBean.setTotalPage(totalPage); pageBean.setTotalRecord(totalRecord); return pageBean; }*/public PageBean<Product> findByPage(int pageNumber, int pageSize) throws SQLException { //创建一个即将被返回的对象 PageBean<Product> PageBean<Product> pageBean = new PageBean<Product>( pageNumber , pageSize); ProductDao dao = new ProductDao(); //查询当前页的2条数据 List<Product> data = dao.findByPage( pageBean.getStartIndex() , pageSize); //查询总记录数int totalRecord = dao.findRecord(); //赋值 pageBean.setData(data); pageBean.setTotalRecord(totalRecord); return pageBean; } public List<Product> findAll() throws SQLException { ProductDao dao = new ProductDao(); return dao.findAll(); } publicvoid save(Product product) throws SQLException { ProductDao dao = new ProductDao(); dao.save(product); } public Product findByPid(String pid) throws SQLException { ProductDao dao = new ProductDao(); return dao.findByPid(pid); } publicboolean update(Product product) throws SQLException { ProductDao dao = new ProductDao(); return dao.update(product); } publicint deleteByPid(String pid) throws SQLException { ProductDao dao = new ProductDao(); return dao.deleteByPid(pid); } } package com.baidu.domain; publicclass Product { /* `pid` VARCHAR(32) NOT NULL, `pname` VARCHAR(50) DEFAULT NULL, #商品名称 `market_price` DOUBLE DEFAULT NULL, #商场价 `shop_price` DOUBLE DEFAULT NULL, #商城价 `pimage` VARCHAR(200) DEFAULT NULL, #商品图片路径 `pdate` DATE DEFAULT NULL, #上架时间 `is_hot` INT(11) DEFAULT NULL, #是否热门：0=不热门,1=热门 `pdesc` VARCHAR(255) DEFAULT NULL, #商品描述 `pflag` INT(11) DEFAULT 0, #商品标记：0=未下架(默认值),1=已经下架 `cid` VARCHAR(32) DEFAULT NULL, #分类id*/private String pid; private String pname; privatedouble market_price; privatedouble shop_price; private String pimage; private String pdate; privateint is_hot; private String pdesc; privateint pflag; private String cid; public String getPid() { return pid; } publicvoid setPid(String pid) { this.pid = pid; } public String getPname() { return pname; } publicvoid setPname(String pname) { this.pname = pname; } publicdouble getMarket_price() { return market_price; } publicvoid setMarket_price(double market_price) { this.market_price = market_price; } publicdouble getShop_price() { return shop_price; } publicvoid setShop_price(double shop_price) { this.shop_price = shop_price; } public String getPimage() { return pimage; } publicvoid setPimage(String pimage) { this.pimage = pimage; } public String getPdate() { return pdate; } publicvoid setPdate(String pdate) { this.pdate = pdate; } publicint getIs_hot() { return is_hot; } publicvoid setIs_hot(int is_hot) { this.is_hot = is_hot; } public String getPdesc() { return pdesc; } publicvoid setPdesc(String pdesc) { this.pdesc = pdesc; } publicint getPflag() { return pflag; } publicvoid setPflag(int pflag) { this.pflag = pflag; } public String getCid() { return cid; } publicvoid setCid(String cid) { this.cid = cid; } } publicclass ProductDao { /** * 分页的dao * @param startIndex * @param pageSize * @return * @throws SQLException */public List<Product> findByPage(int startIndex, int pageSize) throws SQLException { QueryRunner queryRunner = new QueryRunner(C3P0Utils.getDataSource()); String sql =" select * from product limit ?,? "; Object [] params = { startIndex , pageSize }; return queryRunner.query(sql, new BeanListHandler<Product>(Product.class), params); } /** * 计算总记录数 * @return * @throws SQLException */publicint findRecord() throws SQLException { QueryRunner queryRunner = new QueryRunner(C3P0Utils.getDataSource()); String sql =" select count(*) from product "; Object [] params = { }; Object object = queryRunner.query(sql, new ScalarHandler(), params); return Integer.valueOf(object.toString()); } public List<Product> findAll() throws SQLException { QueryRunner queryRunner = new QueryRunner(C3P0Utils.getDataSource()); String sql =" select * from product order by pdate desc "; Object [] params = {}; return queryRunner.query(sql, new BeanListHandler<Product>(Product.class), params); } publicvoid save(Product product) throws SQLException { QueryRunner queryRunner = new QueryRunner(C3P0Utils.getDataSource()); String sql =" insert into product values(?,?,?,?,?,?,?,?,?,?) "; Object [] params = { product.getPid() , product.getPname() , product.getMarket_price() , product.getShop_price() , product.getPimage() , product.getPdate() , product.getIs_hot() , product.getPdesc() , product.getPflag() , product.getCid() }; queryRunner.update(sql, params); } public Product findByPid(String pid) throws SQLException { QueryRunner queryRunner = new QueryRunner(C3P0Utils.getDataSource()); String sql =" select * from product where pid = ? "; Object [] params = {pid}; return queryRunner.query(sql, new BeanHandler<Product>(Product.class), params); } publicboolean update(Product product) throws SQLException { QueryRunner queryRunner = new QueryRunner(C3P0Utils.getDataSource()); String sql = " update product set pname = ? , shop_price = ? , pdesc = ? , cid = ? where pid = ? "; Object [] params = { product.getPname() , product.getShop_price() , product.getPdesc() , product.getCid() , product.getPid() }; return queryRunner.update(sql, params) > 0 ; } publicint deleteByPid(String pid) throws SQLException { QueryRunner queryRunner = new QueryRunner(C3P0Utils.getDataSource()); String sql = " delete from product where pid = ? "; Object [] params = { pid }; return queryRunner.update(sql, params) ; } /** * 处理乱码的工具类 * */publicclass EncodingFilter implements Filter { publicvoid destroy() { // TODO Auto-generated method stub } publicvoid doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException { final HttpServletRequest request = (HttpServletRequest)req; HttpServletResponse response = (HttpServletResponse)resp; try { //处理post乱码 request.setCharacterEncoding("utf-8"); //处理响应 response.setHeader("content-type", "text/html;charset=utf-8"); //处理get乱码 HttpServletRequest myRequest = (HttpServletRequest)Proxy.newProxyInstance( EncodingFilter.class.getClassLoader(), request.getClass().getInterfaces(), new InvocationHandler() { @Override public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { //可以对getParameter进行增强 get提交方式 //1.判断是get请求方式 String requestMethod= request.getMethod(); if("GET".equalsIgnoreCase(requestMethod)){ //get提交 只对getParameter方法进行拦截 String methodName = method.getName(); if("getParameter".equals(methodName)){ //get方式 并且 调用的getParameter方法 //获得以前乱码 return 不乱码 String tempValue = request.getParameter(args[0].toString()); //如果没有获得数据 防止空指针if(tempValue == null){ returnnull; } returnnew String(tempValue.getBytes("iso-8859-1"),"utf-8"); } } //不需要增强return method.invoke(request, args); } }); //放行 chain.doFilter(myRequest, response); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } publicvoid init(FilterConfig fConfig) throws ServletException { // TODO Auto-generated method stub } } jsp代码: <%-- 获得数据 并遍历 --%> <c:forEach items="${pageBean.data}" var="product"> <tr onmouseover="this.style.backgroundColor = ‘#F5FAFE‘" onmouseout="this.style.backgroundColor = ‘#fff‘;"> <td style="CURSOR: hand; HEIGHT: 22px" align="center"> <input type="checkbox" name="" value="" /> </td> <td style="CURSOR: hand; HEIGHT: 22px" align="center"> <img src="${pageContext.request.contextPath}/${product.pimage}" style="height: 200px;width:150px" /> </td> <td style="CURSOR: hand; HEIGHT: 22px" align="center"> ${product.cid} </td> <td style="CURSOR: hand; HEIGHT: 22px" align="center"> ${product.pname} </td> <td style="CURSOR: hand; HEIGHT: 22px" align="center"> ${product.shop_price} </td> <td style="CURSOR: hand; HEIGHT: 22px" align="center"> ${product.pdesc} </td> <td align="center" style="HEIGHT: 22px"> <%--编辑 --%> <a href="${pageContext.request.contextPath}/ProductServlet?pid=${product.pid}&method=findByPid"> <img src="${pageContext.request.contextPath}/images/i_edit.gif" border="0" style="CURSOR: hand"> </a> </td> <td align="center" style="HEIGHT: 22px"> <%--查询 --%> <a href="../user/view.html?userID=15"> <img src="${pageContext.request.contextPath}/images/button_view.gif" border="0" style="CURSOR: hand"> </a> </td> <td align="center" style="HEIGHT: 22px"> <%--删除 ctrl + q --%> <a href="${pageContext.request.contextPath}/ProductServlet?method=deleteByPid&pid=${product.pid}"> <img src="${pageContext.request.contextPath}/images/i_del.gif" width="16" height="16" border="0" style="CURSOR: hand"> </a> <%--提示删除 --%> <a href="javascript:void(0)" onclick="deleteByPid(‘${product.pid}‘)"> <img src="${pageContext.request.contextPath}/images/i_del.gif" width="16" height="16" border="0" style="CURSOR: hand"> </a> </td> </tr> </c:forEach> <%-- 获得数据 并遍历 --%> <script> //javascript 需要在写在 header标签中 function deleteByPid(pid){ //alert(pid); //提示用户 var flag = confirm("您确定要删除信息吗?"); if(flag){ //确定删除 //访问服务器删除的Servlet //修改地址栏 跳转路径 等效我们自己点击超链接 location.href="${pageContext.request.contextPath}/ProductServlet?method=deleteByPid&pid="+pid; } } </script> </table> </td> </tr> </TBODY> </table> <!--分页 class="disabled" class="active"--> <div style="width:1100px;margin:0 auto;margin-top:50px;"> <ul class="pagination" style="text-align:center; margin-top:10px;"> <%-- 如果当前页 等于 1 不需要再显示上一页 如果当前不等于1 显示 --%> <c:if test="${pageBean.pageNumber != 1}"> <li ><a href="${pageContext.request.contextPath}/ProductServlet?method=findAll&pageNumber=1" aria-label="Previous"><span aria-hidden="true">«</span></a></li> <li ><a href="${pageContext.request.contextPath}/ProductServlet?method=findAll&pageNumber=${pageBean.pageNumber - 1 }" aria-label="Previous"><span aria-hidden="true">上一页</span></a></li> </c:if> <%-- 循环显示 所有的页数 --%> <c:forEach begin="${pageBean.start}" end="${pageBean.end}" var="num" step="1"> <li ${pageBean.pageNumber == num ? " class=‘active‘" : ""} ><a href="${pageContext.request.contextPath}/ProductServlet?method=findAll&pageNumber=${num}">${num}</a></li> </c:forEach> <%-- 如果当前页小于总页数 显示下一页 --%> <c:if test="${pageBean.pageNumber < pageBean.totalPage}"> <li><a href="${pageContext.request.contextPath}/ProductServlet?method=findAll&pageNumber=${pageBean.pageNumber + 1 }" aria-label="Next"><span aria-hidden="true">下一页</span></a></li> <li><a href="${pageContext.request.contextPath}/ProductServlet?method=findAll&pageNumber=${pageBean.totalPage}" aria-label="Next"><span aria-hidden="true">»</span></a></li> </c:if> </ul> </div> <!-- 分页结束======================= --> 条件查询： 1: 先在首页上查询分类数据,并且遍历显示 分析: select * from product where cid = ? and pname = ?; 含有的可能性: 1.两者都有. 2.两者都没有. 3.有cid但没有pname 4.没有cid但有pname select count(*) from product where 1=1; 伪代码: SQL = " select * from product where 1=1 "; if(cid != null) { SQL += " and cid = ? " } if(pname != null) { SQL += " and pname like ? " } 1: 修改表单 action属性,method属性,name属性,自定义的method判断逻辑. 2: 调用Servlet a : 获得 cid和pname b : 处理 调用service 调用dao(重要) c : 响应 - 将数据存到request里,请求转发给product_list.jsp 3.对jsp页面进行改造 条件查询注意事项: 1 . Dao的sql部分,拼接的问题,使用 where 1=1 解决了脏读、不可重复读、 2 . Dao的参数拼接部分,使用List接收数据,最后将list转换成数组,解决. 3 . 查询完以后将数据返回给页面,但还需要加上,用户传入后台的cid和pname; 切记:条件查询 不可以 和 分页 同一个项目 但以后 条件查询需要和分页结合 4 . 如果条件查询和分页需要做到同一个项目,需要处理参数问题. 5 . PageBean 查询总记录数 --> 如果加入条件查询,查询总记录数时需要加上条件. 案例:代码体现 publicclass ProductServlet extends HttpServlet { protectedvoid doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { try { //获得页面传递的参数 用来执行某段代码 String method = request.getParameter("method"); ProductService pService = new ProductService(); CategoryService cService = new CategoryService(); //根据页面功能执行某段特殊的代码if("findAll".equals(method)){ //执行查询所有的代码 //1.获得 //1.31 获得cid String cid = request.getParameter("cid"); //1.2 获得pname String pname = request.getParameter("pname"); //2.处理 List<Product> pList = pService.findAll( cid , pname ); List<Category> cList = cService.findAll(); //3.响应 //3.1 将数据存到request request.setAttribute("pList", pList); request.setAttribute("cList", cList); request.setAttribute("cid", cid); request.setAttribute("pname", pname); //3.2 请求转发给jsp request.getRequestDispatcher("/admin/product/product_list.jsp").forward(request, response); return; } publicclass ProductDao { /** * 条件查询 * @param cid * @param pname * @return * @throws SQLException */public List<Product> findAll(String cid, String pname) throws SQLException { QueryRunner queryRunner = new QueryRunner(C3P0Utils.getDataSource()); String sql = " select * from product where 1=1 "; //定义一个List 作用 用来保存参数 List<Object> paramList = new ArrayList<Object>(); //cid判断if(cid != null && !"".equals(cid)){ sql += " and cid = ? "; paramList.add(cid); } //pname判断if(pname != null && !"".equals(pname)){ sql += " and pname like ? "; paramList.add("%"+pname+"%"); } //数组的缺陷 长度固定 集合的长度不固定 集合最后转换成数组 Object [] params = paramList.toArray(); return queryRunner.query(sql,new BeanListHandler<Product>(Product.class), params); } <form action="${pageContext.request.contextPath}/ProductServlet" method="post"> <%--隐藏域 --%> <input type="hidden" name="method" value="findAll"/> <table cellpadding="0" cellspacing="0" border="0" width="100%"> <tr> <td height="22" align="center" bgColor="#f5fafe" class="ta_01" style="width: 15%"> 分类 </td> <td class="ta_01" bgColor="#ffffff" style="width: 30%"> <select name="cid" class="form-control"> <option value="">请选择</option> <c:forEach items="${cList}" var="category"> <option ${category.cid==cid ? "selected" : ""} value="${category.cid}">${category.cname}</option> </c:forEach> </select> </td> <td height="22" align="center" bgColor="#f5fafe" class="ta_01" style="width: 15%"> 商品名称： </td> <td class="ta_01" bgColor="#ffffff"> <input type="text" name="pname" size="15" value="${pname}" class="form-control"/> </td> 批量删除: 思想: 前台两套方法: 1 . 表单提交:将所有被选中的数据,的pid传入后台,后台执行批量删除. 2 . 修改sql 修改成 sql=" delete from product where pid in (?) " 数据循环拼接 1,2,4 3 . 开发中会使用jdbc jdbc当中有批处理,也可以处理批量任务. 事务特性: A : 原子性; C : 一致性; I : 隔离性 : isolation 隔离会产生隔离问题 D : 持久性. protectedvoid doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { try { //获得页面传递的参数 用来执行某段代码 String method = request.getParameter("method"); ProductService pService = new ProductService(); CategoryService cService = new CategoryService(); //根据pid删除商品if("deleteByPid".equals(method)){ //1.获得 //获得数组集合 String[] pids = request.getParameterValues("pid"); //2.处理int count = pService.deleteByPid(pids); //3.响应if(count > 0){ response.sendRedirect(request.getContextPath() + "/ProductServlet?method=findAll"); } return; } <td align="center" width="6%"> <input type="button" value="删除选中" onclick="deleteAll()"> <script> function deleteAll(){ //1.提示 var flag = confirm("您确定要删除信息吗?"); if(!flag){ return ; } //2.获得所有选中的pid 获得所有的数组 最后的格式 pid=1&pid=2&pid3.. var pids = $("input[name=‘pid‘]:checked").serialize() ; //3.发送 location.href="${pageContext.request.contextPath}/ProductServlet?method=deleteByPid&"+pids; } </script> </td> <td align="center" width="15%"> 预览图 </td> <td align="center" width="12%"> 商品分类 </td> <td align="center" width="25%"> 商品名称 </td> <td align="center" width="8%"> 商品价格 </td> <td width="11%" align="center"> 描述 </td> <td width="7%" align="center"> 编辑 </td> <td width="7%" align="center"> 查看 </td> <td width="7%" align="center"> 删除 </td> </tr> <%-- 获得数据 并遍历 --%> <c:forEach items="${pList}" var="product"> <tr onmouseover="this.style.backgroundColor = ‘#F5FAFE‘" onmouseout="this.style.backgroundColor = ‘#fff‘;"> <td style="CURSOR: hand; HEIGHT: 22px" align="center"> <input type="checkbox" name="pid" value="${product.pid}" /> </td> <td style="CURSOR: hand; HEIGHT: 22px" align="center"> <img src="${pageContext.request.contextPath}/${product.pimage}" style="height: 200px;width:150px" /> </td> <td style="CURSOR: hand; HEIGHT: 22px" align="center"> ${product.cid} </td> <td style="CURSOR: hand; HEIGHT: 22px" align="center"> ${product.pname} </td> <td style="CURSOR: hand; HEIGHT: 22px" align="center"> ${product.shop_price} </td> <td style="CURSOR: hand; HEIGHT: 22px" align="center"> ${product.pdesc} </td> <td align="center" style="HEIGHT: 22px"> <%--编辑 --%> <a href="${pageContext.request.contextPath}/ProductServlet?pid=${product.pid}&method=findByPid"> <img src="${pageContext.request.contextPath}/images/i_edit.gif" border="0" style="CURSOR: hand"> </a> </td> <td align="center" style="HEIGHT: 22px"> <%--查询 --%> <a href="../user/view.html?userID=15"> <img src="${pageContext.request.contextPath}/images/button_view.gif" border="0" style="CURSOR: hand"> </a> </td> <td align="center" style="HEIGHT: 22px"> <%--删除 ctrl + q --%> <a href="${pageContext.request.contextPath}/ProductServlet?method=deleteByPid&pid=${product.pid}"> <img src="${pageContext.request.contextPath}/images/i_del.gif" width="16" height="16" border="0" style="CURSOR: hand"> </a> <%--提示删除 --%> <a href="javascript:void(0)" onclick="deleteByPid(‘${product.pid}‘)"> <img src="${pageContext.request.contextPath}/images/i_del.gif" width="16" height="16" border="0" style="CURSOR: hand"> </a> </td> </tr> </c:forEach> <%-- 获得数据 并遍历 --%> <script> //javascript 需要在写在 header标签中 function deleteByPid(pid){ //alert(pid); //提示用户 var flag = confirm("您确定要删除信息吗?"); if(flag){ //确定删除 //访问服务器删除的Servlet //修改地址栏 跳转路径 等效我们自己点击超链接 location.href="${pageContext.request.contextPath}/ProductServlet?method=deleteByPid&pid="+pid; } } </script> </table> </td> </tr> </TBODJY> </table> 数据库开启手动提交以后,只要commit以后,会改成自动提交.查一下是否改成了自动提交
原文：https://www.cnblogs.com/haizai/p/11442985.html
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