通过 StAX 解析时元素返回为 NULL

问题描述

我正在尝试读取 XML 文件元素的属性，为此我使用了 jdom2 和 Stax 库。

    private String readIncludeAll(String filePath) throws JDOMException,IOException,XMLStreamException {
        String includeAll = null;

        Document document = getStAXParsedDocument(filePath);
        Element rootNode = document.getRootElement();
        logger.info("ROOT: "+rootNode );
        List <Element> children=rootNode.getChildren();
        for(int i=0;i<children.size();i++){
            logger.info("CHILDREN:" +children.get(i).toString());
        }
        Element includeElement=rootNode.getChild("includeAll");
        logger.info("INCLUDE ELEMENT: "+includeElement);
       // includeAll=includeElement.getAttributeValue("path");
        //logger.info("VALOR DE PATH: "+includeAll);
        return includeAll;
    }

    private Document getStAXParsedDocument(final String fileName) throws JDOMException,FileNotFoundException,XMLStreamException {
            XMLInputFactory factory = XMLInputFactory.newFactory();
            XMLEventReader reader = factory.createXMLEventReader(new FileReader(fileName));
            StAXEventBuilder builder = new StAXEventBuilder();
        return builder.build(reader);
    }

我尝试在控制台中打印根元素的子元素，而 includeAll 确实是根元素的子元素。为什么它被返回为 NULL？

ROOT: [Element: <databaseChangeLog [Namespace: http://www.liquibase.org/xml/ns/dbchangelog]/>]
CHILDREN:[Element: <includeAll [Namespace: http://www.liquibase.org/xml/ns/dbchangelog]/>]
INCLUDE ELEMENT: null

解决方法

使用带有本地名称和命名空间 http://www.jdom.org/docs/apidocs/org/jdom2/Element.html#getChild(java.lang.String,%20org.jdom2.Namespace) 的 getChild 重载，即 rootNode.getChild("includeAll",Namespace.get("http://www.liquibase.org/xml/ns/dbchangelog"))