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本文用DOM、SAX、DOM4J、JDOM和JDK1.6中新增的StAX生成XML数据格式，并返回XML字符串形式。这里说一下StAX方式。
JDK6的新特性StAX(JSR 173)是JDK6.0中除了DOM和SAX之外的又一种处理XML文档的API StAX的来历 在JAXP1.3(JSR 206)有两种处理XML文档的方法:DOM(Document Object Model)和SAX(Simple API forXML).由于JDK6.0中的JAXB2(JSR 222)和JAX-WS 2.0(JSR224)都会用到StAX所以Sun决定把StAX加入到JAXP家族当中来，并将JAXP的版本升级到1.4(JAXP1.4是JAXP1.3的维护版本),JDK6里面JAXP的版本就是1.4。 StAX是The Streaming API for XML的缩写，一种利用拉模式解析(pull-parsing)XML文档的API.StAX通过提供一种基于事件迭代器(Iterator)的API让程序员去控制xml文档解析过程,程序遍历这个事件迭代器去处理每一个解析事件，解析事件可以看做是程序拉出来的，也就是程序促使解析器产生一个解析事件然后处理该事件，之后又促使解析器产生下一个解析事件，如此循环直到碰到文档结束符；SAX也是基于事件处理xml文档，但却是用推模式解析，解析器解析完整个xml文档后，才产生解析事件，然后推给程序去处理这些事件；DOM采用的方式是将整个xml文档映射到一颗内存树，这样就可以很容易地得到父节点和子结点以及兄弟节点的数据，但如果文档很大，将会严重影响性能。import java.io.BufferedWriter;
import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.FileWriter;import java.io.IOException;import java.io.OutputStreamWriter;import java.io.PrintWriter;import java.io.StringWriter;import java.io.UnsupportedEncodingException;import java.util.List;import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;import javax.xml.parsers.ParserConfigurationException;import javax.xml.stream.XMLEventReader;import javax.xml.stream.XMLOutputFactory;import javax.xml.stream.XMLStreamException;import javax.xml.stream.XMLStreamWriter;import javax.xml.transform.OutputKeys;import javax.xml.transform.Result;import javax.xml.transform.Transformer;import javax.xml.transform.TransformerConfigurationException;import javax.xml.transform.TransformerException;import javax.xml.transform.TransformerFactory;import javax.xml.transform.dom.DOMSource;import javax.xml.transform.sax.SAXTransformerFactory;import javax.xml.transform.sax.TransformerHandler;import javax.xml.transform.stax.StAXSource;import javax.xml.transform.stream.StreamResult;import org.dom4j.DocumentFactory;
import org.dom4j.io.OutputFormat;import org.dom4j.io.XMLWriter;import org.jdom.Document;import org.jdom.Element;import org.jdom.output.XMLOutputter;import org.w3c.dom.Node;import org.w3c.dom.Text;import org.xml.sax.SAXException;import org.xml.sax.helpers.AttributesImpl;/**
* DOM、SAX、DOM4J、JDOM、StAX生成XML，返回各种方式生成XML的字符串形式 * <p> * <cities><city><id>151</id><name>长沙市</name></city><city><id>152</id><name>永州市</name></city></cities>
* </p> * @author * */public class CreateXMLText {/**
* DOM方式生成XML * @param cityList * @return */ public String domToXml(List<City> list) { String xmlStr = null; try { if (null != list && !list.isEmpty()) {// 实例化DOM生成工厂
DocumentBuilderFactory dbf = DocumentBuilderFactory .newInstance(); // 由工厂实例化文档创建器 DocumentBuilder db = dbf.newDocumentBuilder();// 由文档创建器实例化文档对象
org.w3c.dom.Document doc = db.newDocument(); // 文档对象创建一个根元素<cities> org.w3c.dom.Element cities = doc.createElement("cities"); doc.appendChild(cities);for (City po : list) {
// 创建<cities>的子元素<city>
org.w3c.dom.Element cityElt = doc.createElement("city");
cities.appendChild(cityElt);// 创建<city>的子元素<id>
org.w3c.dom.Element idElt = doc.createElement("id");
cityElt.appendChild(idElt);// 创建子元素<id>的文本值
// 第一种方式 // Text idTxt = doc.createTextNode(String.valueOf(c.getId()));
// idElt.appendChild(idTxt); // 第二种方式 idElt.setTextContent(String.valueOf(po.getId()));// 创建<city>的子元素<name>
org.w3c.dom.Element nameElt = doc.createElement("name");
cityElt.appendChild(nameElt);// 创建子元素<name>的文本值
Text nameTxt = doc.createTextNode(po.getName()); nameElt.appendChild(nameTxt);// nameElt.setTextContent(po.getName());}
xmlStr = getDomXml(doc); } } catch (ParserConfigurationException e) { e.printStackTrace(); } System.out.println("DOM:" + xmlStr); return xmlStr; }/**
* 将org.w3c.dom.Document内容转化成String * * @param doc * @return */ private String getDomXml(Node doc) { String xmlStr = null; try { // 以 Document Object Model（DOM）树的形式充当转换 Source 树的持有者 DOMSource source = new DOMSource(doc); //用来生成XML文件 // 要生成文件需构造PrintWriter的writer,//DOM中这种方式name的值没有写进去,由于编码的问题// PrintWriter writerXml = new PrintWriter(new FileOutputStream("city-dom.xml"));
//用OutputStreamWriter加了编码就OK了 PrintWriter writerXml = new PrintWriter(new OutputStreamWriter(newFileOutputStream("city-jdom.xml"),"utf-8"));
Result resultXml = new StreamResult(writerXml); // 实现此接口的对象包含构建转换结果树所需的信息// Result resultXml = new StreamResult(new FileOutputStream("city-dom.xml"));
//用来得到XML字符串形式
// 一个字符流，可以用其回收在字符串缓冲区中的输出来构造字符串。 StringWriter writerStr = new StringWriter(); Result resultStr = new StreamResult(writerStr); // 此抽象类的实例能够将源树转换为结果树。 Transformer transformer = TransformerFactory.newInstance() .newTransformer(); // 设置编码 transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8"); // 是否缩进 transformer.setOutputProperty(OutputKeys.INDENT, "yes"); // 将 XML Source 转换为 Result transformer.transform(source, resultXml); transformer.transform(source, resultStr);//获取XML字符串
xmlStr = writerStr.getBuffer().toString(); } catch (TransformerException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } return xmlStr; }/**
* SAX方式生成XML * * @param list * @return */ public String saxToXml(List<City> list) { String xmlStr = null; try { //用来生成XML文件 // 要生成文件需构造PrintWriter的writer// PrintWriter writerXml = new PrintWriter("city-sax.xml");// Result resultXml = new StreamResult(writerXml); // 实现此接口的对象包含构建转换结果树所需的信息 Result resultXml = new StreamResult(new FileOutputStream("city-sax.xml"));
//用来得到XML字符串形式 // 一个字符流，可以用其回收在字符串缓冲区中的输出来构造字符串 StringWriter writerStr = new StringWriter(); // 构建转换结果树所需的信息。 Result resultStr = new StreamResult(writerStr); // 创建SAX转换工厂 SAXTransformerFactory sff = (SAXTransformerFactory)SAXTransformerFactory
.newInstance(); // 转换处理器，侦听 SAX ContentHandler //解析事件，并将它们转换为结果树 Result TransformerHandler th = sff.newTransformerHandler(); // 将源树转换为结果树 Transformer transformer = th.getTransformer(); // 设置字符编码 transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8"); // 是否缩进 transformer.setOutputProperty(OutputKeys.INDENT, "yes"); //设置与用于转换的此 TransformerHandler 关联的 Result //注：这两个th.setResult不能同时启用// th.setResult(resultXml); th.setResult(resultStr); th.startDocument(); AttributesImpl attr = new AttributesImpl(); th.startElement("", "", "cities", attr); if (null != list && !list.isEmpty()) { for (int i = 0; i < list.size(); i++) { th.startElement("", "", "city", attr);th.startElement("", "", "id", attr);
String id = String.valueOf(list.get(i).getId()); th.characters(id.toCharArray(), 0, id.length()); th.endElement("", "", "id");th.startElement("", "", "name", attr);
String name = String.valueOf(list.get(i).getName());
th.characters(name.toCharArray(), 0, name.length());
th.endElement("", "", "name");th.endElement("", "", "city");
} }th.endElement("", "", "cities");
th.endDocument(); xmlStr = writerStr.getBuffer().toString(); } catch (TransformerConfigurationException e) { e.printStackTrace(); } catch (SAXException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } System.out.println("SAX:" + xmlStr); return xmlStr; }/**
* StAX生成XML，它是The Streaming API for XML简称 * JDK1.6的新增 * @param list * @return */ public String stAXToXml( List<City> list ){ String xmlStr = null; try { if (null != list && !list.isEmpty()) { StringWriter writerStr = new StringWriter(); PrintWriter writerXml = new PrintWriter(newOutputStreamWriter(new FileOutputStream("city-StAX.xml"),"utf-8"));
//定义用于获取 XMLEventWriter 和 XMLStreamWriter 的工厂抽象实现 XMLOutputFactory xof = XMLOutputFactory.newInstance(); //指定如何写XML，注：以下两行只能启用一行// XMLStreamWriter xmlsw = xof.createXMLStreamWriter(writerStr);
XMLStreamWriter xmlsw = xof.createXMLStreamWriter(writerXml);
//写入XML文档声明 xmlsw.writeStartDocument("UTF-8", "1.0"); xmlsw.writeStartElement("cities"); // 写入注释到xml文档 xmlsw.writeComment("省和城市信息"); for (City po : list) { xmlsw.writeStartElement("city"); //添加<id>节点 xmlsw.writeStartElement("id"); xmlsw.writeCharacters(String.valueOf(po.getId())); // 结束<id>节点 xmlsw.writeEndElement(); //添加<name>节点 xmlsw.writeStartElement("name"); xmlsw.writeCharacters(po.getName()); // 结束<name>节点 xmlsw.writeEndElement(); xmlsw.writeEndElement(); } // 结束<cities>节点 xmlsw.writeEndElement(); // 结束 XML 文档 xmlsw.writeEndDocument(); xmlsw.flush(); xmlsw.close(); xmlStr = writerStr.getBuffer().toString(); writerStr.close(); } } catch (XMLStreamException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } System.out.println("StAX:" + xmlStr ); return xmlStr; } /** * JDOM方式生成XML * * @param list * @return */ public String jdomToXml(List<City> list) { String xmlStr = null; try { // 创建文档根节点<cities> Element citiesElt = new Element("cities"); if (null != list && !list.isEmpty()) { for (City po : list) { // 创建子元素节点<city> Element cityElt = new Element("city"); // 创建子元素节点<id> Element idElt = new Element("id"); // 向元素<city>中添加子元素<id> cityElt.addContent(idElt); // 添加id文本 idElt.addContent(String.valueOf(po.getId())); // 创建元素节点<name> Element nameElt = new Element("name"); // 向元素<city>中添加子元素<name> cityElt.addContent(nameElt); // 添加name文本 nameElt.addContent(po.getName()); // 在文档根节点添加子节点<city> citiesElt.addContent(cityElt); } } Document doc = new Document(citiesElt); XMLOutputter out = new XMLOutputter(); //获得XML字符串形式 xmlStr = out.outputString(doc); //生成XML文件 PrintWriter writer = new PrintWriter(new OutputStreamWriter(newFileOutputStream("city-jdom.xml"),"utf-8"));
out.output(doc, writer); writer.flush(); writer.close(); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } System.out.println("JDOM:" + xmlStr); return xmlStr; }/**
* DOM4J生成XML * * @param list * @return */ public String dom4jToXml(List<City> list) { String strXml = null; try { if (null != list && !list.isEmpty()) { DocumentFactory df = DocumentFactory.getInstance(); // org.dom4j.Document doc = DocumentHelper.createDocument();
org.dom4j.Document doc = df.createDocument("UTF-8"); // 创建根节点 org.dom4j.Element citiesElt = doc.addElement("cities"); for (City po : list) { // 在节点<cities>下增加子节点<city> org.dom4j.Element cityElt = citiesElt.addElement("city");
// 在节点<city>下增加子节点<id> org.dom4j.Element idElt = cityElt.addElement("id");
idElt.addText(String.valueOf(po.getId())); // 在节点<city>下增加子节点<name> org.dom4j.Element nameElt = cityElt.addElement("name");
nameElt.addText(po.getName()); } // 有样式(缩进)的写出 OutputFormat opf = OutputFormat.createPrettyPrint(); opf.setEncoding("UTF-8"); opf.setTrimText(true); //生成XML文件 XMLWriter xmlOut = new XMLWriter(new FileOutputStream("city-dom4j.xml"), opf);
xmlOut.write(doc); xmlOut.flush(); xmlOut.close(); //获取XML字符串形式 StringWriter writerStr = new StringWriter(); XMLWriter xmlw = new XMLWriter(writerStr, opf); xmlw.write(doc); strXml = writerStr.getBuffer().toString(); // 无样式的 // strXml = doc.asXML(); } } catch (IOException e) { e.printStackTrace(); } System.out.println("DOM4J:" + strXml); return strXml; }public static void main(String[] args) throws Exception {
List<City> list = City.getCityList(101L); CreateXMLText xml = new CreateXMLText(); xml.domToXml(list); xml.saxToXml(list); xml.stAXToXml(list); xml.dom4jToXml(list); xml.jdomToXml(list); }}