Dom4j

1.使用dom4j创建XML文件

		Document doc = DocumentHelper.createDocument();
		doc.addProcessingInstruction("xml-stylesheet",
				"type='text/xsl' href='student.xsl'");
		// 创建根元素
		// Element root = DocumentHelper.createElement("students");
		// doc.setRootElement(root);
		Element root = doc.addElement("students");
		Element stu1 = root.addElement("student");
		Element stu1Name = stu1.addElement("name");
		Element stu1Age = stu1.addElement("age");
		stu1Name.setText("zhangsan");
		stu1Age.setText("23");
		Element stu2 = root.addElement("student");
		Element stu2Name = stu2.addElement("name");
		Element stu2Age = stu2.addElement("age");
		stu2Name.setText("lisi");
		stu2Age.setText("24");
		Element stu3 = root.addElement("student");
		Element stu3Name = stu3.addElement("name");
		Element stu3Age = stu3.addElement("age");
		stu3Name.setText("wangwu");
		stu3Age.setText("25");
		// 自定义格式化
		// OutputFormat format = new OutputFormat();
		// format.setIndent(" ");
		// format.setNewlines(true);
		// format.setEncoding("gbk");
		// 调用dom4j默认常量
		OutputFormat format = OutputFormat.createPrettyPrint();
		format.setEncoding("gbk");
		try {
			XMLWriter writer = new XMLWriter(format);
			writer.write(doc);
			writer.close();
			// writer.flush();
			// PrintWriter out = new PrintWriter(System.out);
			// doc.write(out);
			// out.close();
		} catch (IOException e) {
			e.printStackTrace();
		}

 2.xml文件的解析(访问者模式)

	public static void main(String[] args) {
		SAXReader saxReader = new SAXReader();
		Document doc = null;
		try{
			doc = saxReader.read(new File("student.xml"));
			doc.accept(new MyVistor());
		}catch(DocumentException e){
			e.printStackTrace();
		}
	}
	private static class MyVistor extends VisitorSupport{
		public void visit(Attribute node) {
			System.out.println("Attribute:"+node.getName()+"="+node.getValue());
		}
		public void visit(Element node) {
			if(node.isTextOnly()){
				System.out.println("Element:"+node.getName()+"="+node.getText());
			}else{
				System.out.println("----------"+node.getName()+"--------");
			}
		}
		public void visit(ProcessingInstruction node) {
			System.out.println("PI:"+node.getName()+"="+node.getText());
		}
	}

 3.Handler的使用

	public static void main(String[] args) {
		SAXReader saxReader = new SAXReader();
		saxReader.addHandler("/students/student",new StudentHandler());
		try{
			saxReader.read(new File("student.xml"));
		}catch(DocumentException e){
			e.printStackTrace();
		}
	}
	private static class StudentHandler implements ElementHandler {
		public void onStart(ElementPath path) {
			Element elt = path.getCurrent();
			System.out.println("Founnd student:"+elt.attributeValue("sn"));
			path.addHandler("name",new NameHandler());
		}
		public void onEnd(ElementPath path) {
			path.removeHandler("name");
		}
	}
	private static class NameHandler implements ElementHandler{
		public void onStart(ElementPath path){
			System.out.println(path.getPath());
		}
		public void onEnd(ElementPath path){
			Element elt = path.getCurrent();
			System.out.println(elt.getName()+":"+elt.getText());
		}
	}

 4.使用dom4j对xml文件的综合操作

// 修改xml文件
	public int modifyXMLFile(String fileName, String newFileName)
			throws Exception {
		int returnValue = 0;
		SAXReader saxReader = new SAXReader();
		Document document = saxReader.read(new File(fileName));
		try {
			List list = document.selectNodes("/books/book/@show");
			Iterator iter = list.iterator();
			while (iter.hasNext()) {
				Attribute attribute = (Attribute) iter.next();
				if (attribute.getValue().equals("yes")) {
					attribute.setValue("no");
				}
			}
			list = document.selectNodes("books/owner");
			iter = list.iterator();
			if (iter.hasNext()) {
				Element ownerElement = (Element) iter.next();
				ownerElement.setText("xiaocai");
				Element dateElement = ownerElement.addElement("date");
				dateElement.setText("2010-06-02");
				dateElement.addAttribute("type", "Gregorian calendar");
			}
			list = document.selectNodes("books/book");
			iter = list.iterator();
			while (iter.hasNext()) {
				Element bookElement = (Element) iter.next();
				Iterator iterator = bookElement.elementIterator();
				while (iterator.hasNext()) {
					Element titleElement = (Element) iterator.next();
					if (titleElement.getText().equals("zhangsan title")) {
						bookElement.remove(titleElement);
					}
				}
			}
		} catch (RuntimeException e) {
			throw e;
		}
		try {
			XMLWriter writer = new XMLWriter(new FileWriter(new File(
					newFileName)));
			writer.write(document);
			writer.flush();
			returnValue = 1;
		} catch (Exception e) {
			throw e;
		}
		return returnValue;
	}
	/**
	 * 格式化xml文件 
	 * OutputFormat format = new OutputFormat();
	 * format.setIndent(" ");
	 * format.setNewlines(true); format.setEncoding("gbk");
	 */
	public int formatXML(String fileName) throws Exception {
		/** 格式化输出,类型IE浏览一样 */
		int returnValue = 0;
		SAXReader saxReader = new SAXReader();
		Document document = saxReader.read(new File(fileName));
		OutputFormat format1 = OutputFormat.createPrettyPrint();
		format1.setEncoding("gbk");
		try {
			XMLWriter writer = new XMLWriter(
					new FileWriter(new File(fileName)), format1);
			writer.write(document);
			writer.close();
			returnValue = 1;
		} catch (UnsupportedEncodingException e) {
			throw e;
		}
		return returnValue;
	}
	// 创建xml文件
	public int createXMLFile(String fileName) throws Exception {
		int returnValue = 0;
		Document document = DocumentHelper.createDocument();
		Element booksElement = document.addElement("books");
		booksElement.addComment("This is a test for dom4jdemo");
		Element book1 = booksElement.addElement("book");
		book1.addAttribute("show", "yes");
		Element title1 = book1.addElement("title");
		title1.addText("zhangsan title");
		Element book2 = booksElement.addElement("book");
		book2.addAttribute("show", "yes");
		Element title2 = book2.addElement("title");
		title2.addText("lisi title");
		Element book3 = booksElement.addElement("book");
		book3.addAttribute("show", "yes");
		Element title3 = book3.addElement("title");
		title3.addText("wangwu title");
		Element owner = booksElement.addElement("owner");
		owner.addText("xc");
		try {
			XMLWriter writer = new XMLWriter(new FileWriter(new File(fileName)));
			writer.write(document);
			writer.close();
			returnValue = 1;
		} catch (Exception e) {
			throw e;
		}
		return returnValue;
	}
	public static void main(String[] args) {
		Dom4jDemo dom = new Dom4jDemo();
		try {
			// dom.createXMLFile("dom4j.xml");
			// dom.modifyXMLFile("dom4j.xml","dom4jnew.xml");
			// dom.formatXML("dom4jnew.xml");
		} catch (Exception e) {
			e.printStackTrace();
		}
	}