如何仅获取具有值 Stax 的元素

Question

我试图只获取具有文本的元素，例如 xml ：

<root>
      <Item>
        <ItemID>4504216603</ItemID>
        <ListingDetails>
          <StartTime>10:00:10.000Z</StartTime>
          <EndTime>10:00:30.000Z</EndTime>
          <ViewItemURL>http://url</ViewItemURL>
            ....
           </item> 

它应该打印

Element Local Name:ItemID
Text:4504216603
Element Local Name:StartTime
Text:10:00:10.000Z
Element Local Name:EndTime
Text:10:00:30.000Z
Element Local Name:ViewItemURL
Text:http://url

此代码还打印根、项目等。是否有可能，它一定是我只是无法谷歌它。

XMLInputFactory inputFactory = XMLInputFactory.newInstance();
InputStream input = new FileInputStream(new File("src/main/resources/file.xml"));
XMLStreamReader xmlStreamReader = inputFactory.createXMLStreamReader(input);

while (xmlStreamReader.hasNext()) {
    int event = xmlStreamReader.next();

    if (event == XMLStreamConstants.START_ELEMENT) {
    System.out.println("Element Local Name:" + xmlStreamReader.getLocalName());
    }

    if (event == XMLStreamConstants.CHARACTERS) {
                        if(!xmlStreamReader.getText().trim().equals("")){
                        System.out.println("Text:"+xmlStreamReader.getText().trim());
                        }
                }

            }

编辑不正确的行为：

    Element Local Name:root
    Element Local Name:item
    Element Local Name:ItemID
    Text:4504216603
    Element Local Name:ListingDetails
    Element Local Name:StartTime
    Text:10:00:10.000Z
    Element Local Name:EndTime
    Text:10:00:30.000Z
    Element Local Name:ViewItemURL
    Text:http://url

我不希望打印没有文本的根节点和其他节点，只打印我上面写的输出。谢谢

Answer 1

试试这个：

while (xmlStreamReader.hasNext()) {
    int event = xmlStreamReader.next();

    if (event == XMLStreamConstants.START_ELEMENT) {
        try {
            String text = xmlStreamReader.getElementText();
            System.out.println("Element Local Name:" + xmlStreamReader.getLocalName());
            System.out.println("Text:" + text);
        } catch (XMLStreamException e) {

        }
    }

}

基于 SAX 的解决方案（有效）：

public class Test extends DefaultHandler {

    public static void main(String[] args) throws ParserConfigurationException, IOException, SAXException, XPathExpressionException, XMLStreamException {
        SAXParser parser = SAXParserFactory.newInstance().newSAXParser();
        parser.parse(new File("src/file.xml"), new Test());
    }

    private String currentName;

    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
        currentName = qName;
    }

    @Override
    public void characters(char[] ch, int start, int length) throws SAXException {
        String string = new String(ch, start, length);
        if (hasText(string)) {
            System.out.println(currentName);
            System.out.println(string);
        }
    }

    private boolean hasText(String string) {
        string = string.trim();
        return string.length() > 0;
    }
}

Answer 2

Stax 解决方案：

解析文档

public void parseXML(InputStream xml) {
        try {

            DOMResult result = new DOMResult();
            XMLInputFactory xmlInputFactory = XMLInputFactory.newInstance();
            XMLEventReader reader = xmlInputFactory.createXMLEventReader(new StreamSource(xml));
            TransformerFactory transFactory = TransformerFactory.newInstance();
            Transformer transformer = transFactory.newTransformer();
            transformer.transform(new StAXSource(reader), result);
            Document document = (Document) result.getNode();

            NodeList startlist = document.getChildNodes();

            processNodeList(startlist);

        } catch (Exception e) {
            System.err.println("Something went wrong, this might help :\n" + e.getMessage());
        }
    }

现在文档中的所有节点都在 NodeList 中，因此接下来执行此操作：

private void processNodeList(NodeList nodelist) {
        for (int i = 0; i < nodelist.getLength(); i++) {
            if (nodelist.item(i).getNodeType() == Node.ELEMENT_NODE && (hasValidAttributes(nodelist.item(i)) || hasValidText(nodelist.item(i)))) {
                getNodeNamesAndValues(nodelist.item(i));
            }
            processNodeList(nodelist.item(i).getChildNodes());
        }
    }

然后对于具有有效文本的每个元素节点，获取名称和值

public void getNodeNamesAndValues(Node n) {

        String nodeValue = null;
        String nodeName = null;

        if (hasValidText(n)) {
            while (n != null && isWhiteSpace(n.getTextContent()) == true && StringUtils.isWhitespace(n.getTextContent()) && n.getNodeType() != Node.ELEMENT_NODE) {
                n = n.getFirstChild();
            }

            nodeValue = StringUtils.strip(n.getTextContent());
            nodeName = n.getLocalName();

            System.out.println(nodeName + " " + nodeValue);

        }
    }

一堆有用的方法来检查节点：

private static boolean hasValidAttributes(Node node) {
        return (node.getAttributes().getLength() > 0);

    }

private boolean hasValidText(Node node) {
        String textValue = node.getTextContent();

        return (textValue != null && textValue != "" && isWhiteSpace(textValue) == false && !StringUtils.isWhitespace(textValue) && node.hasChildNodes());
    }

private boolean isWhiteSpace(String nodeText) {
        if (nodeText.startsWith("\r") || nodeText.startsWith("\t") || nodeText.startsWith("\n") || nodeText.startsWith(" "))
            return true;
        else
            return false;
    }

我还使用了 StringUtils，您可以通过以下方式获得：如果您使用 maven ，请将其包含在您的 pom.xml 中：

<dependency>
            <groupId>commons-lang</groupId>
            <artifactId>commons-lang</artifactId>
            <version>2.5</version>
        </dependency>

如果您正在读取大文件，则效率很低，但如果您先拆分它们，则效率不高。这就是我带来的（与谷歌）。还有更多更好的解决方案，这是我的，我是业余爱好者（目前）。