如何仅从xml文件中删除encoding = UTF8

Question

public static void saveXMLDocument(Document xodrDoc, String absoluteFileName) throws Exception{
    //write the content into xml file                    
    TransformerFactory transformerFactory = TransformerFactory.newInstance();
    Transformer transformer = transformerFactory.newTransformer();
    transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
    DOMSource source = new DOMSource(xodrDoc);
    StreamResult result = new StreamResult(new File(absoluteFileName));
    transformer.transform(source, result);
}

So this is how my output file looks like when i try deleting only the "encoding" attribute:

<OpenDRIVE>
<header date="Wed May 23 12:21:34 2018" east="0.0000000000000000e+00" name="" north="0.0000000000000000e+00" revMajor="1" revMinor="4" south="0.0000000000000000e+00" version="1.00" west="0.0000000000000000e+00">
</header>
<road id="7" junction="-1" length="1.0000000000000000e+03" name="">
    <link>
    </link>
    <planView>
        <geometry hdg="0.0000000000000000e+00" length="1.0000000000000000e+01" s="0.0000000000000000e+00" x="0.0000000000000000e+00" y="0.0000000000000000e+00">
            <line/>
        </geometry>
        <geometry hdg="0.0000000000000000e+00" length="22" s="1.0000000000000000e+01" x="1.0000087425259599e+01" y="0.0000000000000000e+00">
            <arc curvature="0.10"/>
        </geometry>
    </planView>

What should the output be like:

<?xml version="1.0" standalone="yes"?>
<OpenDRIVE>
<header revMajor="1" revMinor="4" name="" version="1.00" date="Wed May 23 12:21:34 2018" north="0.0000000000000000e+00" south="0.0000000000000000e+00" east="0.0000000000000000e+00" west="0.0000000000000000e+00">
</header>
<road name="" length="1.0000000000000000e+03" id="7" junction="-1">
    <link>
    </link>
    <planView>
        <geometry s="0.0000000000000000e+00" x="0.0000000000000000e+00" y="0.0000000000000000e+00" hdg="0.0000000000000000e+00" length="1.0000000000000000e+01">
            <line/>
        </geometry>
        <geometry s="1.0000000000000000e+01" x="1.0000087425259599e+01" y="0.0000000000000000e+00" hdg="0.0000000000000000e+00" length="9.9000000000000000e+02">
            <arc curvature="5.0000000000000001e-04"/>
        </geometry>
    </planView>

So I know I should not delete the encoding part but it is important to me as otherwise I can't work with this file because I use a special tool for the loading. The excpected output is a pattern I load in my programm. After saving it again I get the current output.

The xml file has to contain the standalone attribute but not the encoding part.

Answer 1

You can make use of ProcessingInstruction which lets you configure any tag you want to append.

In this example I am adding a tag "xml" with the custom data that you specified in your case.

ProcessingInstruction newPI = xodrDoc.createProcessingInstruction("xml", "version=\"1.0\" standard=\"yes\"");
            xodrDoc.insertBefore(newPI, xodrDoc.getDocumentElement());

I have created a sample class to test adding the custom xml header.

public class SaveXmlWithCustomXmlHeader {

    public static void main(String[] args) throws Exception {
        String xmlString = "<a><b></b><c></c></a>";

        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder;
        Document document = null;
        try {
            builder = factory.newDocumentBuilder();
            document = builder.parse(new InputSource(new StringReader(xmlString)));
        } catch (Exception e) {
            e.printStackTrace();
        }
        saveXMLDocument(document, "hello.xml");
    }

    public static void saveXMLDocument(Document xodrDoc, String absoluteFileName) throws Exception {
        // add custom xml tag
        ProcessingInstruction newPI = xodrDoc.createProcessingInstruction("xml", "version=\"1.0\" standard=\"yes\"");
        xodrDoc.insertBefore(newPI, xodrDoc.getDocumentElement());

        //write the content into xml file
        TransformerFactory transformerFactory = TransformerFactory.newInstance();
        Transformer transformer = transformerFactory.newTransformer();
        transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
        transformer.setOutputProperty(OutputKeys.INDENT, "yes");
        DOMSource source = new DOMSource(xodrDoc);
        StreamResult result = new StreamResult(new File(absoluteFileName));

        transformer.transform(source, result);
    }
}

Output of hello.xml:

<?xml version="1.0" standard="yes"?><a>
<b/>
<c/>
</a>

UPDATE: There seems to be a problem when using ProcessingInstruction while writing to the file, as it does not indent correctly the xml header from the rest of the xml data.

Normally, this would not change in anyway the processing the xml, as it is just a human readable thing, not a technical issue.

But for the ones that do care, here is the alternative to the ProcessingInstruction :

public static void saveXMLDocument(Document xodrDoc, String absoluteFileName) throws Exception {
        // add custom xml tag
        //write the content into xml file
        TransformerFactory transformerFactory = TransformerFactory.newInstance();
        Transformer transformer = transformerFactory.newTransformer();
        transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
        transformer.setOutputProperty(OutputKeys.INDENT, "yes");
        StringWriter writer = new StringWriter();
        writer.append("<?xml version=\"1.0\" standalone=\"yes\"?>").append("\n");
        final DOMSource source = new DOMSource(xodrDoc);
        transformer.transform(source, new StreamResult(writer));
        try (BufferedWriter bufferedWriter = Files.newBufferedWriter(Paths.get(absoluteFileName))) {
            bufferedWriter.write(writer.toString());
        }
    }

Answer 2

These requirements are stupid, but whatever.

There is a reason why XML is an industry standard. It's a simple text format that can be easily tinkered.

After you've written your XML file, load it back into a String in memory, add "<?xml version=\\"1.0\\" standalone=\\"yes\\"?>" at the beginning of it, and write that back into your file.

Answer 3

使用sed ：

sed -i 's/encoding=".*?"//' myfile.xml