XML解析
三种解析XML方式
package xml.dom;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.OutputKeys;
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.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
import xml.XmlDocument;
/**
* 1.DOM生成和解析XML文档
为 XML 文档的已解析版本定义了一组接口。
解析器读入整个文档，然后构建一个驻留内存的树结构，
然后代码就可以使用 DOM 接口来操作这个树结构。
优点：整个文档树在内存中，便于操作；支持删除、
修改、重新排列等多种功能；缺点：
将整个文档调入内存（包括无用的节点），
浪费时间和空间；使用场合：一旦解析了文档还需多次访问这些数据；
硬件资源充足（内存、CPU）。
* */
public class DomDemo implements XmlDocument{
private Document document;
private String fileName;
public void init() {
try {
DocumentBuilderFactory factory = DocumentBuilderFactory
.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
this.document = builder.newDocument();
} catch (ParserConfigurationException e) {
System.out.println("启动失败");
}
}
// public void createXml(String fileName) {
// Element root = this.document.createElement("employees");
// this.document.appendChild(root);
// Element employee = this.document.createElement("employee");
// Element name = this.document.createElement("name");
// name.appendChild(this.document.createTextNode("丁宏亮"));
// employee.appendChild(name);
// Element sex = this.document.createElement("sex");
// sex.appendChild(this.document.createTextNode("m"));
// employee.appendChild(sex);
// Element age = this.document.createElement("age");
// age.appendChild(this.document.createTextNode("30"));
// employee.appendChild(age);
// root.appendChild(employee);
// TransformerFactory tf = TransformerFactory.newInstance();
// try {
// Transformer transformer = tf.newTransformer();
// DOMSource source = new DOMSource(document);
// transformer.setOutputProperty(OutputKeys.ENCODING, "gb2312");
// transformer.setOutputProperty(OutputKeys.INDENT, "yes");
// PrintWriter pw = new PrintWriter(new FileOutputStream(fileName));
// StreamResult result = new StreamResult(pw);
// transformer.transform(source, result);
// System.out.println("生成XML文件成功!");
// } catch (TransformerConfigurationException e) {
// System.out.println(e.getMessage());
// } catch (IllegalArgumentException e) {
// System.out.println(e.getMessage());
// } catch (FileNotFoundException e) {
// System.out.println(e.getMessage());
// } catch (TransformerException e) {
// System.out.println(e.getMessage());
// }
//}
public void parserXml(String fileName) {
try {
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document document = db.parse(fileName);
NodeList nodeList = document.getChildNodes();
for (int i = 0; i < nodeList.getLength(); i++) {
Node node = nodeList.item(i);
System.out.println("node "+node.getNodeName());
NodeList subSubNodeList = node.getChildNodes();
for (int j = 0; j < subSubNodeList.getLength(); j++) {
Node subSubNode = subSubNodeList.item(j);
System.out.println("subSubNode "+subSubNode.getNodeName());
NodeList finalNodeList = subSubNode.getChildNodes();
for (int k = 0; k < finalNodeList.getLength(); k++) {
System.out.println(finalNodeList.item(k).getNodeName()
);
}
}
}
System.out.println("解析完毕");
} catch (FileNotFoundException e) {
System.out.println("error");
} catch (ParserConfigurationException e) {
System.out.println("error");
} catch (SAXException e) {
System.out.println("error");
} catch (IOException e) {
System.out.println("error");
}
}
}
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package xml.dom4j;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Writer;
import java.util.Iterator;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
import xml.XmlDocument;
/**
*
* @author hongliang.dinghl
* Dom4j 生成XML文档与解析XML文档
* 3.DOM4J生成和解析XML文档
DOM4J 是一个非常非常优秀的Java XML API，
具有性能优异、功能强大和极端易用使用的特点，
同时它也是一个开放源代码的软件。
如今你可以看到越来越多的 Java 软件都在使用 DOM4J 来读写 XML，
特别值得一提的是连 Sun 的 JAXM 也在用 DOM4J。
*/
public class Dom4jDemo implements XmlDocument {
public void createXml(String fileName) {
Document document = DocumentHelper.createDocument();
Element employees=document.addElement("employees");
Element employee=employees.addElement("employee");
Element name= employee.addElement("name");
name.setText("ddvip");
Element sex=employee.addElement("sex");
sex.setText("m");
Element age=employee.addElement("age");
age.setText("29");
try {
Writer fileWriter=new FileWriter(fileName);
XMLWriter xmlWriter=new XMLWriter(fileWriter);
xmlWriter.write(document);
xmlWriter.close();
} catch (IOException e) {
System.out.println(e.getMessage());
}
}
public void parserXml(String fileName) {
File inputXml=new File(fileName);
SAXReader saxReader = new SAXReader();
try {
Document document = saxReader.read(inputXml);
Element root=document.getRootElement();
System.out.println("root "+root.getName());
for(Iterator i = root.elementIterator(); i.hasNext();){
Element subRoot = (Element) i.next();
System.out.println("subRoot "+subRoot.getName());
for(Iterator j = subRoot.elementIterator(); j.hasNext();){
Element finalNode=(Element) j.next();
System.out.println("finalNode "+finalNode.getName()+":"+finalNode.getText());
}
}
} catch (DocumentException e) {
System.out.println(e.getMessage());
}
System.out.println("dom4j parserXml");
}
}
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package xml.sax;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import xml.XmlDocument;
/**
* 2.SAX生成和解析XML文档
为解决DOM的问题，
出现了SAX。
SAX ，事件驱动。
当解析器发现元素开始、
元素结束、文本、文档的开始或结束等时，
发送事件，程序员编写响应这些事件的代码，
保存数据。
优点：不用事先调入整个文档，占用资源少；
SAX解析器代码比DOM解析器代码小，适于Applet，
下载。缺点：不是持久的；事件过后，若没保存数据，那么数据就丢了；
无状态性；从事件中只能得到文本，但不知该文本属于哪个元素；
使用场合：Applet;只需XML文档的少量内容，很少回头访问；
机器内存少；
* */
public class SaxDemo implements XmlDocument {
public void createXml(String fileName) {
System.out.println("<<"+fileName+">>");
}
public void parserXml(String fileName) {
SAXParserFactory saxfac = SAXParserFactory.newInstance();
try {
SAXParser saxparser = saxfac.newSAXParser();
InputStream is = new FileInputStream(fileName);
saxparser.parse(is, new MySAXHandler());
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
class MySAXHandler extends DefaultHandler {
boolean hasAttribute = false;
Attributes attributes = null;
public void startDocument() throws SAXException {
System.out.println("文档开始打印了");
}
public void endDocument() throws SAXException {
System.out.println("文档打印结束了");
}
public void startElement(String uri, String localName, String qName,
Attributes attributes) throws SAXException {
if (qName.equals("employees")) {
return;
}
if (qName.equals("employee")) {
System.out.println(qName);
}
if (attributes.getLength() > 0) {
this.attributes = attributes;
this.hasAttribute = true;
}
}
public void endElement(String uri, String localName, String qName)
throws SAXException {
if (hasAttribute && (attributes != null)) {
for (int i = 0; i < attributes.getLength(); i++) {
System.out.println(attributes.getQName(0)
+ attributes.getValue(0));
}
}
}
public void characters(char[] ch, int start, int length)
throws SAXException {
System.out.println(new String(ch, start, length));
}
}
