Java dom4j操作xml文件方法

1. dom4j创建xml文件

/**
 * 创建文档
 */
@Test
public void createDocument() {
    //创建一篇文档
    Document doc = DocumentHelper.createDocument();
    
    //添加一个元素
    Element root = doc.addElement("catalog");
    //为root元素添加注释
    root.addComment("An XML Catalog");
    //添加标记
    root.addProcessingInstruction("target", "instruction");
    
    //创建元素
    Element journalEl = new BaseElement("journal");
    //添加属性
    journalEl.addAttribute("title", "XML Zone");
    journalEl.addAttribute("publisher", "IBM developerWorks");
    root.add(journalEl);
    
    //添加元素
    Element articleEl = journalEl.addElement("article");
    articleEl.addAttribute("level", "Intermediate");
    articleEl.addAttribute("date", "December-2001");
    
    Element titleEl = articleEl.addElement("title");
    //设置文本内容
    titleEl.setText("Java configuration with XML Schema");
    //titleEl.addText("Java configuration with XML Schema");
    
    Element authorEl = articleEl.addElement("author");
    authorEl.addElement("firstname").setText("Marcello");
    authorEl.addElement("lastname").addText("Vitaletti");
    
    //可以使用 addDocType() 方法添加文档类型说明。 
    doc.addDocType("catalog", null,"file://c:/Dtds/catalog.dtd"); 
 
    fail(doc.getRootElement().getName());
    
    //将xml转换成文本
    fail(doc.asXML());
    
    //写入到文件
    XMLWriter output;
    try {
        output = new XMLWriter(new FileWriter(new File("file/catalog.xml")));
        output.write(doc);
        output.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

2. dom4j查找xml文件的内容

public class GetNodes1 {
    /**
     * 将driver、url、username、password的值读取出来
     */
    public static void main(String[] args) throws IOException, DocumentException {
        SAXReader reader = new SAXReader();
        Document document = reader.read("d:/SqlMapConfig.xml");
        Element driverElement = (Element)document.selectSingleNode("/configuration/environments/environment/dataSource/property[@name='driver']");
        Element urlElement = (Element)document.selectSingleNode("/configuration/environments/environment/dataSource/property[@name='url']");
        Element usernameElement = (Element)document.selectSingleNode("/configuration/environments/environment/dataSource/property[@name='username']");
        Element passwordElement = (Element)document.selectSingleNode("/configuration/environments/environment/dataSource/property[@name='password']");
        String driver = driverElement.attributeValue("value");
        String url = urlElement.attributeValue("value");
        String username = usernameElement.attributeValue("value");
        String password = passwordElement.attributeValue("value");
        
        System.out.println("driver:"+driver+",url:"+url+",username:"+username+",password:"+password);
    }
}

3. dom4j修改XML文件

public class UpdateNode {
    /**
     * 修改密码为123456
     */
    public static void main(String[] args) throws DocumentException, IOException {
        //读取并修改
        SAXReader reader = new SAXReader();
        Document document = reader.read("d:/SqlMapConfig.xml");
        Element passwordElement = (Element)document.selectSingleNode("/configuration/environments/environment/dataSource/property[@name='password']");
        passwordElement.addAttribute("value", "123456");
        //保存
        OutputStream os = new FileOutputStream("d:/SqlMapConfig.xml");
        XMLWriter writer = new XMLWriter(os,OutputFormat.createPrettyPrint());
        writer.write(document);
        writer.close();
        os.close();
    }
}

4. dom4j删除XML文件的某个结点元素

public class DeleteNode {
    /**
     * 删除密码结点
     */
    public static void main(String[] args) throws DocumentException, IOException {
        //找到结点并删除
        SAXReader reader = new SAXReader();
        Document document = reader.read("d:/SqlMapConfig.xml");
        Element passwordElement = (Element) document.selectSingleNode("/configuration/environments/environment/dataSource/property[@name='password']");
        passwordElement.getParent().remove(passwordElement);
        
        //保存
        OutputStream os = new FileOutputStream("d:/SqlMapConfig.xml");
        XMLWriter writer = new XMLWriter(os,OutputFormat.createPrettyPrint());
        writer.write(document);
        writer.close();
        os.close();
    }
}

5. dom4j删除文档内容

/**
 * <b>function:</b> 删除节点内容
 */
@Test
public void removeNode() {
    try {
        Document doc = reader.read(new File("file/catalog-modified.xml"));
        fail("comment: " + doc.selectSingleNode("//comment()"));
        //删除注释
        doc.getRootElement().remove(doc.selectSingleNode("//comment()"));
        
        Element node = (Element) doc.selectSingleNode("//article");
        //删除属性
        node.remove(new DOMAttribute(QName.get("level"), "Introductory"));
        //删除元素 节点
        node.remove(doc.selectSingleNode("//title"));
        
        //只能删除下一级节点，不能超过一级；（需要在父元素的节点上删除子元素）
        Node lastNameNode = node.selectSingleNode("//lastname");
        lastNameNode.getParent().remove(lastNameNode);
        
        fail("Text: " + doc.selectObject("//*[text()='Ayesha']"));
        Element firstNameEl = (Element)doc.selectObject("//firstname");
        fail("Text: " + firstNameEl.selectSingleNode("text()"));
        
        //删除text文本
        //firstNameEl.remove(firstNameEl.selectSingleNode("text()"));
        //firstNameEl.remove(doc.selectSingleNode("//firstname/text()"));
        firstNameEl.remove(doc.selectSingleNode("//*[text()='Ayesha']/text()"));
        
        //删除子元素author
        //node.remove(node.selectSingleNode("//author"));
        
        fail(doc.asXML());
    } catch (Exception e) {
        e.printStackTrace();
    }
}