解析xml文件

DOM4J

DOM4J生成和解析XML文档DOM4J 是一个非常非常优秀的Java XML API，具有性能优异、功能强大和极端易用使用的特点，同时它也是一个开放源代码的软件。如今你可以看到越来越多的 Java 软件都在使用 DOM4J 来读写 XML，特别值得一提的是连 Sun 的 JAXM 也在用 DOM4J。

/**
 * Dom4j 生成XML文档与解析XML文档
 */
public class Dom4jDemo implements XmlDocument {
    public void createXml(String fileName) {
        Document document = DocumentHelper.createDocument();
        Element employees = document.addElement("employees");
        Element employee = employees.addElement("employee");
        Element name = employee.addElement("name");
        name.setText("桥本有菜");
        Element sex = employee.addElement("sex");
        sex.setText("女");
        Element age = employee.addElement("age");
        age.setText("24");
        try {
            Writer fileWriter = new FileWriter(fileName);
            XMLWriter xmlWriter = new XMLWriter(fileWriter);
            xmlWriter.write(document);
            xmlWriter.close();
        } catch (IOException e) {
            System.out.println(e.getMessage());
        }
    }

    public void parserXml(String fileName) {
        File inputXml = new File(fileName);
        SAXReader saxReader = new SAXReader();
        try {
            Document document = saxReader.read(inputXml);
            Element employees = document.getRootElement();
            for (Iterator i = employees.elementIterator(); i.hasNext(); ) {
                Element employee = (Element) i.next();
                for (Iterator j = employee.elementIterator(); j.hasNext(); ) {
                    Element node = (Element) j.next();
                    System.out.println(node.getName() + ":" + node.getText());
                }
            }
        } catch (DocumentException e) {
            System.out.println(e.getMessage());
        }
        System.out.println("dom4j parserXml");
    }
} 

DOM

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）。

/**
 * DOM生成与解析XML文档
 */
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("角色"));
        employee.appendChild(name);
        Element sex = this.document.createElement("sex");
        sex.appendChild(this.document.createTextNode("女"));
        employee.appendChild(sex);
        Element age = this.document.createElement("age");
        age.appendChild(this.document.createTextNode("24"));
        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());
        }
    }
}