Android，org.w3c.dom：没有验证的DocumentBuilder实现可用 [英] Android, org.w3c.dom: No validating DocumentBuilder implementation available

问题描述

我试图在Android 2.3.3上解析XML文档，但似乎没有验证的解析器。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）。

I'm trying to parse an XML document on Android 2.3.3, but it seems that there is no validating parser. The reason I need validation for is to ignore whitespaces in the XML file (blanks, carriage returns, line feeds, etc.).

这是我要解析文档：

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

文件是文件位置的URL作为字符串。当执行此代码的最后一行时，会抛出以下异常：

file is the URL to the file location as string. When executing the last line of this code the following exception is thrown:

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

当我取出 dbfac.setValidating（true），没有异常，但是我有空白的问题。

When I take out dbfac.setValidating(true), no exception occurs, but then I have the problem with the whitespaces.

有谁知道如何解决这个问题？我必须使用另一个解析器吗？

Does anyone know how to solve this problem? Do I have to use another parser?

推荐答案

在Android上，实现是硬编码的，当验证集设置为真正。这里是 Android源代码链接：

On Android, the implementation is hard coded to throw the exception when validation set set to true. Here is the 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;
}

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