java - 序列化 XML 子项并在 Java 中保留 namespace

Question

我有一个 Document像这样对 XML 进行建模的对象:

<RootNode xmlns="http://a.com/a" xmlns:b="http://b.com/b">
    <Child />
</RootNode>

使用 Java DOM，我需要获取 <Child>节点并将其序列化为 XML，但保留根节点 namespace 。这是我目前拥有的，但它没有序列化命名空间:

public static void main(String[] args) throws Exception {
    String xml = "<RootNode xmlns='http://a.com/a' xmlns:b='http://b.com/b'><Child /></RootNode>";

    DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
    Document doc = builder.parse(new ByteArrayInputStream(xml.getBytes()));
    Node childNode = doc.getFirstChild().getFirstChild();

    // serialize to string
    StringWriter sw = new StringWriter();
    DOMSource domSource = new DOMSource(childNode);
    StreamResult streamResult = new StreamResult(sw);
    TransformerFactory tf = TransformerFactory.newInstance();
    Transformer serializer = tf.newTransformer();
    serializer.transform(domSource, streamResult);
    String serializedXML = sw.toString();

    System.out.println(serializedXML);
}

当前输出:

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

预期输出:

<?xml version="1.0" encoding="UTF-8"?>
<Child xmlns='http://a.com/a' xmlns:b='http://b.com/b' />

Answer 1

您需要明确地将您的 DocumentBuilderFactory 设置为命名空间感知:

DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
dbf.setNamespaceAware(true);
DocumentBuilder db = dbf.newDocumentBuilder();