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如何在Java的XPath中运行时禁用DTD?
原标题:
  • 时间:2008-10-28 15:25:38
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我在文件中得到了DTD,但我无法将其删除。当我尝试在Java中解析它时,由于它是远程DTD,我得到了“Caused by:java.net.SocketException:Network is unreachable:connect”。我可以在某种程度上禁用DTD检查吗?

最佳回答

你应该能够指定自己的实体解析器,或使用解析器的特定功能?在这里查看一些方法。

一个更完整的例子:

<?xml version="1.0"?>
<!DOCTYPE foo PUBLIC "//FOO//" "foo.dtd">
<foo>
    <bar>Value</bar>
</foo>

XPath 的使用:

import java.io.File;
import java.io.IOException;
import java.io.StringReader;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathFactory;

import org.w3c.dom.Document;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

public class Main {

    public static void main(String[] args) throws Exception {
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder = factory.newDocumentBuilder();

        builder.setEntityResolver(new EntityResolver() {

            @Override
            public InputSource resolveEntity(String publicId, String systemId)
                    throws SAXException, IOException {
                System.out.println("Ignoring " + publicId + ", " + systemId);
                return new InputSource(new StringReader(""));
            }
        });
        Document document = builder.parse(new File("src/foo.xml"));
        XPathFactory xpathFactory = XPathFactory.newInstance();
        XPath xpath = xpathFactory.newXPath();
        String content = xpath.evaluate("/foo/bar/text()", document
                .getDocumentElement());
        System.out.println(content);
    }
}

希望这有所帮助...

问题回答

这对我有效:

 SAXParserFactory saxfac = SAXParserFactory.newInstance();
  saxfac.setValidating(false);
  try {
    saxfac.setFeature("http://xml.org/sax/features/validation", false);
    saxfac.setFeature("http://apache.org/xml/features/nonvalidating/load-dtd-grammar", false);
    saxfac.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);
    saxfac.setFeature("http://xml.org/sax/features/external-general-entities", false);
    saxfac.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
  }
  catch (Exception e1) {
    e1.printStackTrace();
  }

我以前遇到过这个问题。我通过下载并存储DTD的本地副本来解决它,然后根据本地副本进行验证。您需要编辑XML文件以指向本地副本。

<!DOCTYPE root-element SYSTEM "filename">

这里有更多信息:http://www.w3schools.com/dtd/dtd_intro.asp

我认为您也可以在解析器中手动设置某种validateOnParse属性为“false”。这取决于您用于解析XML的库。

更多信息请参见:http://www.w3schools.com/dtd/dtd_validation.asp





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