如何用StAX合并具有一定条件的两个XML文件

import javax.xml.stream.*;
import java.io.*;

public class XMLMerger {
    public static void main(String[] args) {
        try {
            // 创建XML输入流1
            XMLInputFactory inputFactory = XMLInputFactory.newInstance();
            XMLStreamReader reader1 = inputFactory.createXMLStreamReader(new FileInputStream("file1.xml"));

            // 创建XML输入流2
            XMLStreamReader reader2 = inputFactory.createXMLStreamReader(new FileInputStream("file2.xml"));

            // 创建XML输出流
            XMLOutputFactory outputFactory = XMLOutputFactory.newInstance();
            XMLStreamWriter writer = outputFactory.createXMLStreamWriter(new FileOutputStream("merged.xml"));

            // 遍历第一个XML文件
            while (reader1.hasNext()) {
                int event = reader1.next();

                // 判断条件，例如判断元素名称为"book"的节点
                if (event == XMLStreamConstants.START_ELEMENT && reader1.getLocalName().equals("book")) {
                    // 合并节点
                    writeNode(reader1, writer);
                    
                    // 遍历第二个XML文件
                    while (reader2.hasNext()) {
                        int event2 = reader2.next();
                        
                        // 判断条件，例如判断元素名称为"book"且属性值为"123"的节点
                        if (event2 == XMLStreamConstants.START_ELEMENT && reader2.getLocalName().equals("book") && reader2.getAttributeValue(null, "id").equals("123")) {
                            // 合并节点
                            writeNode(reader2, writer);
                            break;
                        }
                    }
                }
            }

            // 关闭输入输出流
            reader1.close();
            reader2.close();
            writer.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    // 将节点写入XML输出流
    private static void writeNode(XMLStreamReader reader, XMLStreamWriter writer) throws XMLStreamException {
        writer.writeStartElement(reader.getLocalName());

        // 复制节点的属性
        for (int i = 0; i < reader.getAttributeCount(); i++) {
            writer.writeAttribute(reader.getAttributeLocalName(i), reader.getAttributeValue(i));
        }

        // 复制节点的文本内容
        if (reader.hasNext()) {
            int event = reader.next();
            if (event == XMLStreamConstants.CHARACTERS) {
                writer.writeCharacters(reader.getText());
            }
        }

        writer.writeEndElement();
    }
}