以编程方式将XML声明添加到XML文档

<?xml version="1.0" encoding="UTF-8"?>

import xml.etree.ElementTree as ET

# 创建根元素
root = ET.Element("root")

# 创建子元素
child = ET.SubElement(root, "child")
child.text = "Hello, World!"

# 创建XML树
tree = ET.ElementTree(root)

# 添加XML声明
tree.write("output.xml", encoding="UTF-8", xml_declaration=True)

const fs = require('fs');
const { DOMParser, XMLSerializer } = require('xmldom');

// 创建XML文档
const doc = new DOMParser().parseFromString('<root><child>Hello, World!</child></root>', 'application/xml');

// 添加XML声明
doc.documentElement.setAttribute('version', '1.0');
doc.documentElement.setAttribute('encoding', 'UTF-8');

// 序列化XML文档
const serializer = new XMLSerializer();
const xmlString = serializer.serializeToString(doc);

// 写入文件
fs.writeFileSync('output.xml', xmlString);

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

public class XMLExample {
    public static void main(String[] args) throws Exception {
        // 创建DocumentBuilder
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder = factory.newDocumentBuilder();

        // 创建Document
        Document doc = builder.newDocument();

        // 创建根元素
        Element root = doc.createElement("root");
        doc.appendChild(root);

        // 创建子元素
        Element child = doc.createElement("child");
        child.appendChild(doc.createTextNode("Hello, World!"));
        root.appendChild(child);

        // 创建Transformer
        TransformerFactory transformerFactory = TransformerFactory.newInstance();
        Transformer transformer = transformerFactory.newTransformer();

        // 设置XML声明
        transformer.setOutputProperty(javax.xml.transform.OutputKeys.OMIT_XML_DECLARATION, "no");
        transformer.setOutputProperty(javax.xml.transform.OutputKeys.VERSION, "1.0");
        transformer.setOutputProperty(javax.xml.transform.OutputKeys.ENCODING, "UTF-8");

        // 写入文件
        DOMSource source = new DOMSource(doc);
        StreamResult result = new StreamResult(new File("output.xml"));
        transformer.transform(source, result);
    }
}