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); } 4.设置某节点的属性和文字. newMemberElm.addAttribute("name", "sitinspring"); 5.设置属性的文字 Attribute attribute=root.attribute("name"); attribute.setText("sitinspring"); 6.删除某属性 Attribute attribute = root.attribute("size");// 属性名name root.remove(attribute); 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(); 2.文档中含有中文,设置编码格式写入的形式. 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(); 字符串与XML的转换 1.将字符串转化为XML String text = "<members> <member>sitinspring</member> </members>"; Document document = DocumentHelper.parseText(text); 2.将文档或节点的XML转化为字符串. 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(); 使用XPath快速找到节点. 读取的XML文档示例 <?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(); } }