如何在Java中将多个xml文件合并为单个字符串

Question

I have several xml files with different node structure. I want to extract xml content from each of these xml files and store former(xml content) as a single string.

I am using following code to achieve it

   String xmlContent = FileUtils.readFileToString(new File("xyz"), "UTF-8");

but i am facing following error

    [Fatal Error] :5616:15: The processing instruction target matching "[xX][mM][lL]" is not allowed.

After searching i found that aforesaid error occurs because "" present in between the xml content.

Should i first modify xml files or there is any other way handle this situation?

Answer 1

Edit your xml file using a text editor. At the very beginning of the first line, look for and delete any leading spaces.

The following first line of the xml must not have any spaces or characters before the first "<" in the line.

<?xml version="1.0" encoding="UTF-8"?>

Try the import again. refer http://www-01.ibm.com/support/docview.wss?uid=swg21262072

Answer 2

Should i first modify xml files ...

Yes you should.

... and there is any other way handle this situation?

Well, you could attempt to program around the fact that your XML is invalid:

• If the problems are minor and isolated, you could attempt to do an initial pass over the file to "fix" it. Then parse it using a regular XML parser.

• If the problems are too widespread, you could attempt to treat the XML as text and attempt to extract data without parsing properly.

But the problem with both approaches is that you could end up with bad or missing data when your attempts to make good fail; eg because the XML changes to be bad in a different way.

So my recommendation would be to either fix the XML by hand using a text editor (if this is a once) off, or get who / whatever is creating it to fix the problem at source.

---

Incidentally, once you have fixed the XML syntax problems, you may be able to do the picking and merging of the XML files just using XSLT.

Answer 3

After putting some efforts I have combined content into a single xml file :) Following method removes xml encoding node and stringifies xml file.

 public String stringifyXmlFiles(String fileName) {
        File file = new File(fileName);
    String content = "";
    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
    try {
        DocumentBuilder builder = factory.newDocumentBuilder();
        Document document = builder.parse(new FileInputStream(file));

        TransformerFactory tranFactory = TransformerFactory.newInstance();
        Transformer aTransformer = tranFactory.newTransformer();
        aTransformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION,
                "yes");
        aTransformer.setOutputProperty(OutputKeys.INDENT, "yes");
        Source src = new DOMSource(document);
        ByteArrayOutputStream stream = new ByteArrayOutputStream();
        Result dest = new StreamResult(stream);
        aTransformer.transform(src, dest);
        content = stream.toString();
    } catch (ParserConfigurationException e) {
        logger.error(e.getMessage(), e);
    } catch (SAXException e) {
        logger.error(e.getMessage(), e);
    } catch (IOException e) {
        logger.error(e.getMessage(), e);
    } catch (TransformerConfigurationException e) {
        logger.error(e.getMessage(), e);
    } catch (TransformerException e) {
        logger.error(e.getMessage(), e);
    }
    return content;
   }