使用Java构造XML字符串

使用如下工具类可以自行构建想要的XML字符串。需要引入lombok依赖(懒得写get和set方法了)

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
</dependency>

具体实现如下

import java.io.StringWriter;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Objects;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import lombok.AllArgsConstructor;
import lombok.Data;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

public class XmlBuilder {

    public static void main(String[] args) throws Exception {

        List<Node> nodeList = new ArrayList<>();

        nodeList.add(new Node("employee", null, null,List.of(new Node("department","行政处",null,null))));
        System.out.println(build("xml", nodeList));

        List<Node> nodeList2 = new ArrayList<>();
        nodeList2.add(new Node("Parent", null, null,null));
        nodeList2.add(new Node("Child1", "Child1value", null,null));
        nodeList2.add(new Node("Child2", null, Arrays.asList(new Attribute("attribute1", "value1"), new Attribute("attribute2", "value2")),null));
        String xmlString = build("xml", nodeList2);
        System.out.println(xmlString);

    }

    /**
     * 构造XML字符串
     * @param rootElementName 根元素名
     * @param nodeList        节点列表
     * @return 构造的XML字符串
     */
    public static String build(String rootElementName, List<Node> nodeList) throws Exception {

        // 创建DocumentBuilderFactory和DocumentBuilder对象
        DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();

        // 创建新的Document对象和根元素
        Document doc = dBuilder.newDocument();
        Element rootElement = doc.createElement(rootElementName);
        doc.appendChild(rootElement);

        // 添加子节点和属性到根元素
        for (Node node : nodeList) {
            Element element = doc.createElement(node.getName());
            element.setTextContent(node.getValue());
            if (Objects.nonNull(node.getAttributeList())) {
                //设置结点的属性值
                for (Attribute attribute : node.getAttributeList()) {
                    element.setAttribute(attribute.getName(), attribute.getValue());
                }
            } else if (Objects.nonNull(node.getChildrenList())) {
                //如果该结点有子节点，则添加子节点的值
                for (Node child : node.getChildrenList()) {
                    Element childElement = doc.createElement(child.getName());
                    childElement.setTextContent(child.getValue());
                    //设置子结点的属性值
                    if (Objects.nonNull(child.getAttributeList())) {
                        for (Attribute attribute : child.getAttributeList()) {
                            childElement.setAttribute(attribute.getName(), attribute.getValue());
                        }
                    }

                    //添加子节点
                    element.appendChild(childElement);
                }
            }

            //将结点添加到根结点下
            rootElement.appendChild(element);
        }

        Transformer transformer = TransformerFactory.newInstance().newTransformer();
        //去除XML头部声明(<?xml version="1.0" encoding="UTF-8" standalone="no"?>)
        transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
        //启用缩进
        transformer.setOutputProperty(OutputKeys.INDENT, "yes");
        //指定了缩进量,可以将 "2" 替换成其他值，如 "4" 或 "tab" 等
        transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");
        // 设置字符编码
        transformer.setOutputProperty(OutputKeys.ENCODING, StandardCharsets.UTF_8.name());

        // 将新的Document对象转换为字符串输出
        StringWriter writer = new StringWriter();
        transformer.transform(new DOMSource(doc), new StreamResult(writer));
        return writer.toString().trim();
    }

    /**
     * 节点类
     */
    @Data
    @AllArgsConstructor
    public static class Node {
        private final String name;
        private final String value;
        private final List<Attribute> attributeList;
        private final List<Node> childrenList;
    }

    /**
     * 属性类
     */
    @Data
    @AllArgsConstructor
    public static class Attribute {
        private final String name;
        private final String value;
    }
}

测试结果（如果需要xml头部的声明，可自行去除代码的配置即可）

<xml>
  <employee>
    <department>行政处</department>
  </employee>
</xml>

<xml>
  <Parent/>
  <Child1>Child1value</Child1>
  <Child2 attribute1="value1" attribute2="value2"/>
</xml>