dom4j学习笔记

1.加载XML文档
SAXReader reader = new SAXReader();
Document doc = reader.read("src/book.xml");

2.获得根元素
Node root = doc.getRootElement();
或 Element r = doc.getRootElement();

3.取得某节点的单个子节点
Element root = root.getRootElement();
Element memberElm=root.element("member");// "member"是节点名

4.取得节点的文字
String text=memberElm.getText();

5.取得某节点下名为"book"的所有字节点并进行遍历
Element r = doc.getRootElement();
List titles = r.elements("book");
for(int i=0;i<titles.size();i++){
     System.out.println(((Element)titles.get(i)).asXML());
}
6.在某节点下添加子节点.
Element ageElm = newMemberElm.addElement("age");

7.设置节点文字.
ageElm.setText("29");

8.删除某节点.
parentElm.remove(childElm);// childElm是待删除的节点,parentElm是其父节点

属性相关.
1.取得某节点下的某属性
Element root=document.getRootElement(); 
Attribute attribute=root.attribute("size");// 属性名name
2.取得属性的文字
String text=attribute.getText();
也可以用:
String text2=root.element("name").attributeValue("firstname");这个是取得根节点下name字节点的属性firstname的值.

3.遍历某节点的所有属性

Element root = document.getRootElement();
for (Iterator it = root.attributeIterator(); it.hasNext();) {
	Attribute attribute = (Attribute) it.next();
	String text = attribute.getText();
	System.out.println(text);
}

将文档写入XML文件.
1.文档中全为英文,不设置编码,直接写入的形式.

XMLWriter writer = new XMLWriter(new FileWriter("output.xml"));
writer.write(document);
writer.close();

OutputFormat format = OutputFormat.createPrettyPrint();
format.setEncoding("GBK"); // 指定XML编码
XMLWriter writer = new XMLWriter(new FileWriter("output.xml"), format);
writer.write(document);
writer.close();

String text = "<members> <member>sitinspring</member> </members>";
Document document = DocumentHelper.parseText(text);

SAXReader reader = new SAXReader();
Document document = reader.read(new File("input.xml"));
Element root = document.getRootElement();
String docXmlText = document.asXML();
String rootXmlText = root.asXML();
Element memberElm = root.element("member");
String memberXmlText = memberElm.asXML();

<?xml version="1.0" encoding="UTF-8"?>
<projectDescription>
	<name>MemberManagement</name>
	<comment></comment>
	<projects>
		<project>PRJ1</project>
		<project>PRJ2</project>
		<project>PRJ3</project>
		<project>PRJ4</project>
	</projects>
	<buildSpec>
		<buildCommand>
			<name>org.eclipse.jdt.core.javabuilder</name>
			<arguments>
			</arguments>
		</buildCommand>
	</buildSpec>
	<natures>
		<nature>org.eclipse.jdt.core.javanature</nature>
	</natures>
</projectDescription>

使用XPath快速找到节点project.

public static void main(String[] args) {
	SAXReader reader = new SAXReader();
	try {
		Document doc = reader.read(new File("sample.xml"));
		List projects = doc.selectNodes("/projectDescription/projects/project");
		Iterator it = projects.iterator();
		while (it.hasNext()) {
			Element elm = (Element) it.next();
			System.out.println(elm.getText());
		}
	} catch (Exception ex) {
		ex.printStackTrace();
	}
}