利用Java 如何实现解析XML数据

// 1、创建解析器工厂
SAXParserFactory factory = SAXParserFactory.newInstance();
// 2、获得解析器
SAXParser parser = factory.newSAXParser();
// SAX 解析器 ，继承 DefaultHandler
String path = new File("resource/demo01.xml").getAbsolutePath();
// 解析 
parser.parse(path, new MySaxHandler());

// 获取 SAX 解析器
SAXBuilder builder = new SAXBuilder();
File file = new File("resource/demo01.xml");
// 获取文档
Document doc = builder.build(new File(file.getAbsolutePath())); 
// 获取根节点 
Element root = doc.getRootElement(); 
System.out.println(root.getName());
// 获取根节点下所有的子节点， 也可以根据标签名称获取指定的直接点
List<Element> list = root.getChildren();
System.out.println(list.size());
for(int x = 0; x<list.size(); x++){
  Element e = list.get(x); 
  // 获取元素的名称和里面的文本
  String name = e.getName();
  System.out.println(name + "=" + e.getText());
  System.out.println("==================");
}

File file = new File("resource/outputdom4j.xml");
SAXReader reader = new SAXReader();
// 读取文件作为文档
Document doc = reader.read(file);
// 获取文档的根元素
Element root = doc.getRootElement();
// 根据跟元素找到全部的子节点
Iterator<Element> iter = root.elementIterator();
while(iter.hasNext()){
  Element name = iter.next();
  System.out.println("value = " + name.getText());
}

public static void createXml() throws Exception{ 
  //获取解析器工厂 
  DocumentBuilderFactory factory=DocumentBuilderFactory.newInstance(); 
  //获取解析器 
  DocumentBuilder builder=factory.newDocumentBuilder(); 
  //创建文档 
  Document doc=builder.newDocument(); 
  //创建元素、设置关系 
  Element root=doc.createElement("people"); 
  Element person=doc.createElement("person"); 
  Element name=doc.createElement("name"); 
  Element age=doc.createElement("age"); 
  name.appendChild(doc.createTextNode("lebyte")); 
  age.appendChild(doc.createTextNode("10")); 
  doc.appendChild(root); 
  root.appendChild(person); 
  person.appendChild(name); 
  person.appendChild(age); 
  //写出去 
  // 获得变压器工厂 
  TransformerFactory tsf=TransformerFactory.newInstance(); 
  Transformer ts=tsf.newTransformer(); 
  //设置编码 
  ts.setOutputProperty(OutputKeys.ENCODING, "UTF-8"); 
  //创建带有 DOM 节点的新输入源，充当转换 Source 树的持有者 
  DOMSource source=new DOMSource(doc); 
  //充当转换结果的持有者 
  File file=new File("src/output.xml"); 
  StreamResult result=new StreamResult(file); 
  ts.transform(source, result); 
} 

//创建一个SAXtransformerfactory对象
SAXTransformerFactory stf = (SAXTransformerFactory) SAXTransformerFactory.newInstance();
try {
  //通过SAXTransformerFactory对象创建一个TransfomerHandler对象
  TransformerHandler handler = stf.newTransformerHandler();
  //通过transformerHandler对象创建一个transformer对象
  Transformer tf = handler.getTransformer();
  //设置Transfomer对象的属性
  tf.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
  tf.setOutputProperty(OutputKeys.INDENT, "yes");
  //创建一个Result的对象，将其与handler关联
  File file = new File("src/output.xml");
  if(!file.exists()){
    file.createNewFile();
  }
  Result result = new StreamResult(new FileOutputStream(file));
  handler.setResult(result);
  //通过Handler编写XML的内容     
  //打开Document 
  handler.startDocument();
  AttributesImpl attr = new AttributesImpl();
  //创建根节点bookstore
  handler.startElement("", "", "bookstore", attr);
  attr.clear();
  attr.addAttribute("", "", "id", "", "1");
  handler.startElement("", "", "book", attr);
  attr.clear();
  handler.startElement("", "", "name", attr);
  handler.characters("颈椎病康复指南".toCharArray(), 0, "颈椎病康复指南".length());
  handler.endElement("","","name");
  //关闭各节点
  handler.endElement("", "", "book");
  handler.endElement("", "", "bookstore");
  handler.endDocument();
} catch (SAXException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
} catch (FileNotFoundException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
} catch (IOException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
} catch (TransformerConfigurationException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
}

// 创建节点 
Element person = new Element("person"); 
Element name = new Element("name"); 
Element age = new Element("age"); 
// 创建属性 
Attribute id = new Attribute("id","1"); 
// 设置文本 
name.setText("lebyte"); 
age.setText("10"); 
// 设置关系 
Document doc = new Document(person); 
person.addContent(name); 
name.setAttribute(id); 
person.addContent(age); 
XMLOutputter out = new XMLOutputter(); 
File file = new File("resource/outputjdom.xml"); 
out.output(doc, new FileOutputStream(file.getAbsoluteFile())); 

// 使用 DocumentHelper 来创建 Document 对象 
Document document = DocumentHelper.createDocument(); 
// 创建元素并设置关系 
Element person = document.addElement("person"); 
Element name = person.addElement("name");  
Element age = person.addElement("age"); 
// 设置文本 name.setText("lebyte"); 
age.setText("10"); 
// 创建格式化输出器 
OutputFormat of = OutputFormat.createPrettyPrint(); 
of.setEncoding("utf-8"); 
// 输出到文件 
File file = new File("resource/outputdom4j.xml"); 
XMLWriter writer = new XMLWriter(new FileOutputStream(new File(file.getAbsolutePath())),of); 
// 写出 
writer.write(document); 
writer.flush(); 
writer.close();