技术重点主要是XML文档的读写操作。因为前台页面与后台数据分页是使用XML文档进行交互的。本实例将主要介绍DOM技术如何生成XML文档。
代码如下：
try {
???// 创建XML文档构建工厂
???DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
???// 创建XML文档构建对象
???DocumentBuilder documentBuilder = builderFactory.newDocumentBuilder();
???doc = documentBuilder.newDocument(); ???????????// 创建文档对象
} catch (ParserConfigurationException ex) {
???Logger.getLogger(AjaxFenyeService.class.getName()).log(Level.SEVERE, null, ex);
}
Element createElement(String tagName)
tagName：节点的名称。
appendChild(Node newChild)
newChild：Node接口的实现对象，Element类实现了Node接口，所以Element类的实例对象可以直接作为该方法的参数。
Element root = doc.createElement("products"); ??????// 创建XML的根节点
doc.appendChild(root); ?????????????????????????????// 添加根节点到xml文档
PageArgs pageArgs = dao.getPageArgs(); ?????????????// 获取数据分页参数
pageArgs.setPageCount(page); ???????????????????????// 设置当前分页页码
Element pageArg = doc.createElement("pageArg"); ????// 创建分页信息节点
root.appendChild(pageArg); ?????????????????????????// 添加分页信息到根节点
Element pageNumElement = doc.createElement("pageNum");// 添加当前页码参数
pageArg.appendChild(pageNumElement);
public DOMSource(Node node)
node：该参数是DOM节点对象，它作为输入源。
public abstract void transform(Source xmlSource,
??????????????????????????????Result outputTarget)
xmlSource：DOM数据源
outputTarget：保存XML文档的输出流
// 创建XML转换器
Transformer tf = TransformerFactory.newInstance().newTransformer();
OutputStream out = resp.getOutputStream(); ????????????// 获取应答输出流
DOMSource ds = new DOMSource(doc); ??????????????// 创建XML数据源
StreamResult stream = new StreamResult(out);
tf.setOutputProperty(OutputKeys.INDENT, "yes"); ???????// 缩进XML文档格式
tf.transform(ds, stream); ??????????????????????????// 把数据输出到浏览器
out.close();
*******编写index.jsp首页文件，在首页文件中添加<label>标签，设置该标签的id属性为“productList”，它用于保存分页数据。关键代码如下：
<body onload="requestPage(1)">
???<h1>明日科技部分图书介绍列表</h1>
???<label id="productList"></label>
</body>
********在页面中编写JavaScript脚本，创建requestPage()方法，该方法用于创建请求对象，向服务器发送获取分页数据的请求，同时设置服务器返回的数据由readPage()方法处理。关键代码如下。
<script type="text/javascript">
var xmlHttp;
function requestPage(page){
???//初始化对象并发出XMLHttpRequest请求
???if (window.XMLHttpRequest) { ???????????????????????????????????????????????????// Mozilla或其他除IE以外的浏览器
???????xmlHttp = new XMLHttpRequest();
???} else if (window.ActiveXObject) { ?????????????????????????????????????????????????????// IE浏览器
???????try {
???????????xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
???????} catch (e) {
???????????try {
???????????????xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
???????????} catch (e) {}
???????}
???}
???if (!xmlHttp) {
???????alert("不能创建XMLHTTP实例!");
???????return false;
???}
???xmlHttp.onreadystatechange = readPage; ??????????????????????????????????????????????// readPage()方法处理服务器响应
???xmlHttp.open("GET", "fenyeService?page="+page,true); ?????????????????????????// 发送请求对象
???xmlHttp.send(null);
}
*******编写脚本的readPage()方法，服务器返回的分页数据是XML文档格式，该方法在服务器正确返回分页数据时解析XML文档将指定页面数据和分页参数信息添加到页面的<label>标签中，这样就只更新<label>标签中的数据，而不用重新加载整个页面。关键代码如下
function readPage(){
???if(xmlHttp.readyState==4){
???????if(xmlHttp.status==200){
???????????var doc=xmlHttp.responseXML; ??????????????????????????????????????????????????????????// 接收XML文档对象
???????????var pageNum = doc.getElementsByTagName("pageNum")[0].firstChild.data; ???// 获取当前页码参数
???????????var maxPage= doc.getElementsByTagName("maxPage")[0].firstChild.data; ????????????// 获取最大页码参数
???????????var prePage = doc.getElementsByTagName("prePage")[0].firstChild.data; ???????// 获取上一页的页码参数
???????????var nextPage = doc.getElementsByTagName("nextPage")[0].firstChild.data; ???????????// 获取下一页页码参数
???????????var products = doc.getElementsByTagName("product"); ????????????????????????// 获取所有分页数据
???????????var innerHTML = ""; ?????????????????????????????????????????????????????????????// 定义插入<label>标签的数据
???????????if((products!=null)&&(products.length!=0)) {
???????????????innerHTML+="<table border=1 width=‘600‘>"; ???????????????????????????????// 插入表头信息
???????????????innerHTML+="<tr align=‘center‘><th>ISBN</th><th>书名</th>";
???????????????innerHTML+="<th>作者</th><th>出版社</th>";
???????????????innerHTML+="<th>单价</th><th>出版日期</th></tr>";
???????????????for(var i=0;i<products.length;i++) { ??????????????????????????????????????????????// 遍历XML文档的所有图书
???????????????????var product = products[i];
???????????????????var isbn = product.childNodes[0].firstChild.data;
???????????????????var bookName = ?product.childNodes[1].firstChild.data;
???????????????????var writer = ?product.childNodes[2].firstChild.data;
???????????????????var publishing = ?product.childNodes[3].firstChild.data;
???????????????????var price = ?product.childNodes[4].firstChild.data;
???????????????????var date = ?product.childNodes[5].firstChild.data;
???????????????????innerHTML += "<tr>";
???????????????????innerHTML += "<td>"+isbn+"</td>"; ?????????????????????????????????????// 把图书信息插入表格
???????????????????innerHTML += "<td>"+bookName+"</td>";
???????????????????innerHTML += "<td>"+writer+"</td>";
???????????????????innerHTML += "<td>"+publishing+"</td>";
???????????????????innerHTML += "<td>"+price+"</td>";
???????????????????innerHTML += "<td>"+date+"</td>";
???????????????????innerHTML += "</tr>";
???????????????}
???????????????innerHTML+="<tr><td align=‘center‘ colspan=‘6‘>"; ???????????????????????// 添加分页超链接
???????????????innerHTML += "<a href=\"javascript:void(0)\" onClick=\"requestPage(1)\">第一页</a>";
???????????????innerHTML += "<a href=\"javascript:void(0)\" onClick=\"requestPage("+prePage+")\">上一页</a>";
???????????????innerHTML += pageNum+"/"+maxPage;
???????????????innerHTML += "<a href=\"javascript:void(0)\" onClick=\"requestPage("+nextPage+")\">下一页</a>";
???????????????innerHTML +="<a href=\"javascript:void(0)\" onClick=\"requestPage("+maxPage+")\">尾页</a>";
???????????????innerHTML+="</td></tr>\n";
???????????????innerHTML+="</table>\n";
???????????}else {
???????????????innerHTML += "暂时没有任何数据";
???????????}
???????????document.getElementById("productList").innerHTML = innerHTML;
???????} else {
???????????alert(‘您请求的页面发现错误‘);
???????}
???}
}
********编写AjaxFenyeService类，它是处理分页请求的Servlet控制器，该类重写Servlet的doGet()方法，处理分页请求，该方法首先创建XML文档对象，从数据库读取分页参数信息并添加到XML文档对象的根节点中。关键代码如下
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
???try {
???????// 创建XML文档构建工厂
???????DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
???????// 创建XML文档构建对象
???????DocumentBuilder documentBuilder = builderFactory.newDocumentBuilder();
???????doc = documentBuilder.newDocument(); ???????????// 创建文档对象
???} catch (ParserConfigurationException ex) {
???????Logger.getLogger(AjaxFenyeService.class.getName()).log(Level.SEVERE, null, ex);
???}
???List books = null; ??????????????????????????????// 创建数据集合
???resp.setContentType("application/xml"); ????????????????????// 设置应答类型为XML
???// 获取请求对象的分页参数
???int page = ServletRequestUtils.getIntParameter(req, "page", 1);
???Element root = doc.createElement("products"); ??????????????????// 创建XML的根节点
???doc.appendChild(root); ???????????????????????????????????// 添加根节点到xml文档
???PageArgs pageArgs = dao.getPageArgs(); ?????????????// 获取数据分页参数
???pageArgs.setPageCount(page); ?????????????????????????????// 设置当前分页页码
???Element pageArg = doc.createElement("pageArg"); ???????????????// 创建分页信息节点
???root.appendChild(pageArg); ???????????????????????????????// 添加分页信息到根节点
???Element pageNumElement = doc.createElement("pageNum"); ????// 添加当前页码参数
???pageArg.appendChild(pageNumElement);
???Text pageNumValue = doc.createTextNode(pageArgs.getPageNum() + "");
???pageNumElement.appendChild(pageNumValue);
???// 添加最大页码参数
???Element maxPageElement = doc.createElement("maxPage");
???pageArg.appendChild(maxPageElement);
???Text maxPageValue = doc.createTextNode(pageArgs.getMaxPage() + "");
???maxPageElement.appendChild(maxPageValue);
???// 添加下一页的页码参数
???Element nextPageElement = doc.createElement("nextPage");
???pageArg.appendChild(nextPageElement);
???Text nextPageValue = doc.createTextNode(pageArgs.getNextPage() + "");
???nextPageElement.appendChild(nextPageValue);
???// 添加上一页的页码参数
???Element prePageElement = doc.createElement("prePage");
???pageArg.appendChild(prePageElement);
???Text prePageValue = doc.createTextNode(pageArgs.getPrePage() + "");
???prePageElement.appendChild(prePageValue);
???try { ?????????????????????????????????????????????????????????????????????// 添加图书节点
???????books = dao.getProducts(page);
???????for (Object pro : books) {
???????????FenyeBean fenyeBean = (FenyeBean) pro;
???????????Element product = doc.createElement("product");
???????????root.appendChild(product);
???????????Element isbnNode = doc.createElement("ISBN"); ?????????// 创建ISBN节点
???????????product.appendChild(isbnNode);
???????????Text isbnValue = doc.createTextNode(fenyeBean.getIsbn());
???????????isbnNode.appendChild(isbnValue);
???????????Element nameNode = doc.createElement("BookName"); ?????????// 创建bookname节点
???????????product.appendChild(nameNode);
???????????Text nameValue = doc.createTextNode(fenyeBean.getBookName());
???????????nameNode.appendChild(nameValue);
???????????Element writerNode = doc.createElement("Writer"); ????????// 创建Writer节点
???????????product.appendChild(writerNode);
???????????Text writerValue = doc.createTextNode(fenyeBean.getWriter());
???????????writerNode.appendChild(writerValue);
???????????Element pbNode = doc.createElement("Publishing"); ???????// 创建publishing节点
???????????product.appendChild(pbNode);
???????????Text pbValue = doc.createTextNode(fenyeBean.getPublishing());
???????????pbNode.appendChild(pbValue);
???????????Element priceNode = doc.createElement("Price"); ????????// 创建Price节点
???????????product.appendChild(priceNode);
???????????Text priceValue = doc.createTextNode(fenyeBean.getPrice()+"");
???????????priceNode.appendChild(priceValue);
???????????Element dateNode = doc.createElement("Date"); ??????????// 创建Date节点
???????????product.appendChild(dateNode);
???????????Text dateValue = doc.createTextNode(fenyeBean.getDate().toLocaleString());
???????????dateNode.appendChild(dateValue);
???????}
???????// 创建XML转换器
???????Transformer tf = TransformerFactory.newInstance().newTransformer();
???????OutputStream out = resp.getOutputStream(); ???????????????????// 获取应答输出流
???????DOMSource ds = new DOMSource(doc); ????????????????????????// 创建XML数据源
???????StreamResult stream = new StreamResult(out);
???????tf.setOutputProperty(OutputKeys.INDENT, "yes"); ??????????????// 缩进XML文档格式
???????tf.transform(ds, stream); ??????????????????????????????????// 把数据输出到浏览器
???????out.close();
???} catch (Exception ex) {
???????ex.printStackTrace();
???}
}
public class PageArgs {
???private int pageNum; ???????????????????????????????// 当前页码
???private int pageSize; ??????????????????????????// 页面大小
???private long maxPage; ??????????????????????????????// 最大页数
???private int prePage; ??????????????????????????// 上一页的页码
???private int nextPage; ?????????????????????????// 下一页的页码
???public void setPageCount(int pageNum) {
???????this.pageNum = pageNum;
???????prePage=pageNum-1<=1?1:pageNum-1; ????// 设置上一页的页码
???????// 设置下一页的页码
???????nextPage=(int) (pageNum + 1 >= maxPage ? maxPage : pageNum + 1);
???}
……省略部分代码
}
public PageArgs getPageArgs() {
???PageArgs pag = null; ????????????????????????????????????????????????????????// 声明分页参数对象
???Statement stmt = null;
???ResultSet rs = null;
???Connection conn = getConn(); ????????????????????????????????????????????????// 连接数据库
???try {
???????// 声明查询总数据量的SQL语句
???????String sql = "SELECT count(*) FROM tb_hibernatefenye";
???????stmt = conn.createStatement();
???????rs = stmt.executeQuery(sql); ???????????????????????????????????????// 执行SQL查询
???????if (rs.next()) {
???????????int count = rs.getInt(1); ????????????????????????????????????????// 获取查询结果
???????????pag = new PageArgs(); ?????????????????????????????????????????????// 初始化分页参数对象
???????????pag.setPageSize(pageSize); ???????????????????????????????????????????// 设置分页大小
???????????pag.setMaxPage((count + pageSize - 1) / pageSize); ??????????// 设置最大页码
???????????pag.setPageCount(count); ????????????????????????????????????????// 设置当前页码
???????}
???} catch (SQLException ex) {
???????Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, ex);
???} finally {
???????close(rs, stmt, conn);
???}
???return pag;
}
public List getProducts(final int page) throws Exception {
???if (pageSize == 0) {
???????throw new Exception("产品分页的页面大小不能为0");
???}
???List list = new ArrayList(); ????????????????????????????????????// 创建保存分页数据的集合对象
???PreparedStatement stmt = null;
???ResultSet rs = null;
???Connection conn = getConn(); ???????????????????????????????// 连接数据库
???try {
???????// 定义分页查询的SQL语句
???????String sql = "SELECT * FROM tb_Databasetoexcel limit ?,?";
???????stmt = conn.prepareStatement(sql);
???????stmt.setInt(1, (page-1)*pageSize); ??????????????????????????// 设置SQL查询参数
???????stmt.setInt(2, pageSize); ??????????????????????????// 设置SQL查询参数
???????rs = stmt.executeQuery(); ?????????????????????????????????????// 获取查询结果
???????while (rs.next()) { ???????????????????????????????????????????// 遍历查询结果集
???????????FenyeBean fenyeBean = new FenyeBean(); ???????// 创建分页对象
???????????fenyeBean.setIsbn(rs.getString("isbn")); ??????????// 初始化分页对象
???????????fenyeBean.setBookName(rs.getString("bookName"));
???????????fenyeBean.setPublishing(rs.getString("publishing"));
???????????fenyeBean.setWriter(rs.getString("writer"));
???????????fenyeBean.setPrice(rs.getFloat("price"));
???????????fenyeBean.setDate(rs.getDate("date"));
???????????list.add(fenyeBean); ???????????????????????????????????// 添加分页数据对象到List集合
???????}
???} catch (SQLException ex) {
???????Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, ex);
???} finally {
???????close(rs, stmt, conn);
???}
???return list;
}
Ajax无刷新分页
原文地址：https://www.cnblogs.com/hao-lei/p/8360855.html