JAVA解析XML的四种方法
XML现在已经成为一种通用的数据交换格式,它的平台无关性,语言无关性,系统无关性,给数据集成与交互带来了极大的方便。对于XML本身的语法知识与技术细节,需要阅读相关的技术文献,这里面包括的内容有DOM(Document Object Model),DTD(Document Type Definition),SAX(Simple API for XML),XSD(Xml Schema Definition),XSLT(Extensible Stylesheet Language Transformations),
XML在不同的语言里解析方式都是一样的,只不过实现的语法不同而已。基本的解析方式有两种,一种叫SAX,另一种叫DOM。SAX是基于事件流的解析,DOM是基于XML文档树结构的解析。假设我们XML的内容和结构如下:
<?xml version=”1.0″ encoding=”UTF-8″?>
<employees>
<employee>
<name>ddviplinux</name>
<sex>m</sex>
<age>30</age>
</employee>
</employees>
首先定义一个操作XML文档的接口XmlDocument 它定义了XML文档的建立与解析的接口。
package com.alisoft.facepay.framework.bean;
- public interface XmlDocument {
- /**
- * 建立XML文档
- * @param fileName 文件全路径名称
- */
- public void createXml(String fileName);
- /**
- * 解析XML文档
- * @param fileName 文件全路径名称
- */
- 18.public void parserXml(String fileName);
- 19.}
- 20.package com.alisoft.facepay.framework.bean;
- 21./**
- 22. *
- 23. * @author hongliang.dinghl
- * 定义XML文档建立与解析的接口
- */
- public interface XmlDocument {
- /**
- * 建立XML文档
- * @param fileName 文件全路径名称
- */
- public void createXml(String fileName);
- /**
- * 解析XML文档
- * @param fileName 文件全路径名称
- */
- public void parserXml(String fileName);
- }
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(e.getMessage());
- }
- }
- 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 employees = document.getChildNodes();
- for (int i = 0; i < employees.getLength(); i++) {
- Node employee = employees.item(i);
- NodeList employeeInfo = employee.getChildNodes();
- for (int j = 0; j < employeeInfo.getLength(); j++) {
- Node node = employeeInfo.item(j);
- NodeList employeeMeta = node.getChildNodes();
- for (int k = 0; k < employeeMeta.getLength(); k++) {
- System.out.println(employeeMeta.item(k).getNodeName()
- + “:” + employeeMeta.item(k).getTextContent());
- }
- }
- }
- System.out.println(“解析完毕“);
- } catch (FileNotFoundException e) {
- System.out.println(e.getMessage());
- } catch (ParserConfigurationException e) {
- System.out.println(e.getMessage());
- } catch (SAXException e) {
- System.out.println(e.getMessage());
- } catch (IOException e) {
- System.out.println(e.getMessage());
- }
- }
- }