java - 安卓，org.w3c.dom : No validating DocumentBuilder implementation available

Question

我正在尝试在 Android 2.3.3 上解析 XML 文档，但似乎没有验证解析器。我需要验证的原因是忽略 XML 文件中的空格(空格、回车符、换行符等)。

这就是我想要解析文档的方式:

DocumentBuilderFactory dbfac = DocumentBuilderFactory.newInstance();
dbfac.setValidating(true);
dbfac.setIgnoringElementContentWhitespace(true);
DocumentBuilder docBuilder;
docBuilder = dbfac.newDocumentBuilder();
Document d = docBuilder.parse(file);

file 是文件位置的字符串形式的 URL。当执行这段代码的最后一行时，会抛出以下异常:

javax.xml.parsers.ParserConfigurationException: No validating DocumentBuilder implementation available

当我取出 dbfac.setValidating(true) 时，没有发生异常，但是我遇到了空格问题。

有谁知道如何解决这个问题？我必须使用其他解析器吗？

Answer 1

在 Android 上，实现被硬编码为在验证设置为 true 时抛出异常。这是 Android source code link :

@Override
public DocumentBuilder newDocumentBuilder()
        throws ParserConfigurationException {
    if (isValidating()) {
        throw new ParserConfigurationException(
                "No validating DocumentBuilder implementation available");
    }

    /**
     * TODO If Android is going to support a different DocumentBuilder
     * implementations, this should be wired here. If we wanted to
     * allow different implementations, these could be distinguished by
     * a special feature (like http://www.org.apache.harmony.com/xml/expat)
     * or by throwing the full SPI monty at it.
     */
    DocumentBuilderImpl builder = new DocumentBuilderImpl();
    builder.setCoalescing(isCoalescing());
    builder.setIgnoreComments(isIgnoringComments());
    builder.setIgnoreElementContentWhitespace(isIgnoringElementContentWhitespace());
    builder.setNamespaceAware(isNamespaceAware());

    // TODO What about expandEntityReferences?

    return builder;
}