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How to unescape string in XML using Transformer?

I've a function which takes a XML document as parameter and writes it to the file. It contains element as <tag>"some text & some text": <text> text</tag> but in output file it's written as <tag>"some text & some text": <text> text</tag> But I don't want string to be escaped while writing to the file.
Function is,
public static void function(Document doc, String fileUri, String randomId){
DOMSource source = new DOMSource(doc,ApplicationConstants.ENC_UTF_8);
FileWriterWithEncoding writer = null;
try {
File file = new File(fileUri+File.separator+randomId+".xml");
if (!new File(fileUri).exists()){
new File(fileUri).mkdirs();
}
writer = new FileWriterWithEncoding(new File(file.toString()),ApplicationConstants.ENC_UTF_8);
StreamResult result = new StreamResult(writer);
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = null;
transformer = transformerFactory.newTransformer();
transformer.setParameter(OutputKeys.INDENT, "yes");
transformer.transform(source, result);
writer.close();
transformer.clearParameters();
}catch (IOException | TransformerException e) {
log.error("convert Exception is :"+ e);
}
}

There are five escape characters in XML ("'<>&). According to XML grammar, they must be escaped in certain places in XML, please see this question:
What characters do I need to escape in XML documents?
So you can't to much, for instance, to avoid escaping & or < in text content.
You could use CDATA sections if you want to retain "unescaped" content. Please see this question:
Add CDATA to an xml file

Keep numeric character entity characters such as ` ` when parsing XML in Java

I am parsing XML that contains numeric character entity characters such as (but not limited to)
< > (line feed carriage return < >) in Java. While parsing, I am appending text content of nodes to a StringBuffer to later write it out to a textfile.
However, these unicode characters are resolved or transformed into newlines/whitespace when I write the String to a file or print it out.
How can I keep the original numeric character entity characters symbols when iterating over nodes of an XML file in Java and storing the text content nodes to a String?
Example of demo xml file:
<?xml version="1.0" encoding="UTF-8"?>
<ABCD version="2">
<Field attributeWithChar="A string followed by special symbols
" />
</ABCD>
Example Java code. It loads the XML, iterates over the nodes and collects the text content of each node to a StringBuffer. After the iteration is over, it writes the StringBuffer to the console and also to a file (but no
) symbols.
What would be a way to keep these symbols when storing them to a String? Could you please help me? Thank you.
public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException, TransformerException {
DocumentBuilderFactory documentFactory = DocumentBuilderFactory.newInstance();
Document document = null;
DocumentBuilder documentBuilder = documentFactory.newDocumentBuilder();
document = documentBuilder.parse(new File("path/to/demo.xml"));
StringBuilder sb = new StringBuilder();
NodeList nodeList = document.getElementsByTagName("*");
for (int i = 0; i < nodeList.getLength(); i++) {
Node node = nodeList.item(i);
if (node.getNodeType() == Node.ELEMENT_NODE) {
NamedNodeMap nnp = node.getAttributes();
for (int j = 0; j < nnp.getLength(); j++) {
sb.append(nnp.item(j).getTextContent());
}
}
}
System.out.println(sb.toString());
try (Writer writer = new BufferedWriter(new OutputStreamWriter(
new FileOutputStream("path/to/demo_output.xml"), "UTF-8"))) {
writer.write(sb.toString());
}
}

You need to escape all the XML entities before parsing the file into a Document. You do that by escaping the ampersand & itself with its corresponding XML entity &. Something like,
DocumentBuilder documentBuilder =
DocumentBuilderFactory.newInstance().newDocumentBuilder();
String xmlContents = new String(Files.readAllBytes(Paths.get("demo.xml")), "UTF-8");
Document document = documentBuilder.parse(
new InputSource(new StringReader(xmlContents.replaceAll("&", "&"))
));
Output :
2A string followed by special symbols

P.S. This is complement of Ravi Thapliyal's answer, not an alternative.
I am having the same problem with handling an XML file which is exported from 2003 format Excelsheet. This XML file stores line-breaks in text contents as
along with other numeric character references. However, after reading it with Java DOM parser, manipulating the content of some elements and transforming it back to the XML file, I see that all the numeric character references are expanded (i.e. The line-break is converted to CRLF) in Windows with J2SE1.6. Since my goal is to keep the content format unchanged as much as possible while manipulating some elements (i.e. retain numeric character references), Ravi Thapliyal's suggestion seems to be the only working solution.
When writing the XML content back to the file, it is necessary to replace all & with &, right? To do that, I had to give a StringWriter to the transformer as StreamResult and obtain String from it, replace all and dump the string to the xml file.
TransformerFactory tf = TransformerFactory.newInstance();
Transformer t = tf.newTransformer();
DOMSource source = new DOMSource(document);
//write into a stringWriter for further processing.
StringWriter stringWriter = new StringWriter();
StreamResult result = new StreamResult(stringWriter);
t.transform(source, result);
//stringWriter stream contains xml content.
String xmlContent = stringWriter.getBuffer().toString();
//revert "&" back to "&" to retain numeric character references.
xmlContent = xmlContent.replaceAll("&", "&");
BufferedWriter wr = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(outputFile), "UTF-8"));
wr.write(xmlContent);
wr.close();

How to remove extra empty lines from XML file?

In short; i have many empty lines generated in an XML file, and i am looking for a way to remove them as a way of leaning the file. How can i do that ?
For detailed explanation; I currently have this XML file :
<recent>
<paths>
<path>path1</path>
<path>path2</path>
<path>path3</path>
<path>path4</path>
</paths>
</recent>
And i use this Java code to delete all tags, and add new ones instead :
public void savePaths( String recentFilePath ) {
ArrayList<String> newPaths = getNewRecentPaths();
Document recentDomObject = getXMLFile( recentFilePath ); // Get the <recent> element.
NodeList pathNodes = recentDomObject.getElementsByTagName( "path" ); // Get all <path> nodes.
//1. Remove all old path nodes :
for ( int i = pathNodes.getLength() - 1; i >= 0; i-- ) {
Element pathNode = (Element)pathNodes.item( i );
pathNode.getParentNode().removeChild( pathNode );
}
//2. Save all new paths :
Element pathsElement = (Element)recentDomObject.getElementsByTagName( "paths" ).item( 0 ); // Get the first <paths> node.
for( String newPath: newPaths ) {
Element newPathElement = recentDomObject.createElement( "path" );
newPathElement.setTextContent( newPath );
pathsElement.appendChild( newPathElement );
}
//3. Save the XML changes :
saveXMLFile( recentFilePath, recentDomObject );
}
After executing this method a number of times i get an XML file with right results, but with many empty lines after the "paths" tag and before the first "path" tag, like this :
<recent>
<paths>
<path>path5</path>
<path>path6</path>
<path>path7</path>
</paths>
</recent>
Anyone knows how to fix that ?
------------------------------------------- Edit: Add the getXMLFile(...), saveXMLFile(...) code.
public Document getXMLFile( String filePath ) {
File xmlFile = new File( filePath );
try {
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document domObject = db.parse( xmlFile );
domObject.getDocumentElement().normalize();
return domObject;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
public void saveXMLFile( String filePath, Document domObject ) {
File xmlOutputFile = null;
FileOutputStream fos = null;
try {
xmlOutputFile = new File( filePath );
fos = new FileOutputStream( xmlOutputFile );
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
transformer.setOutputProperty( OutputKeys.INDENT, "yes" );
transformer.setOutputProperty( "{http://xml.apache.org/xslt}indent-amount", "2" );
DOMSource xmlSource = new DOMSource( domObject );
StreamResult xmlResult = new StreamResult( fos );
transformer.transform( xmlSource, xmlResult ); // Save the XML file.
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (TransformerConfigurationException e) {
e.printStackTrace();
} catch (TransformerException e) {
e.printStackTrace();
} finally {
if (fos != null)
try {
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

First, an explanation of why this happens — which might be a bit off since you didn't include the code that is used to load the XML file into a DOM object.
When you read an XML document from a file, the whitespaces between tags actually constitute valid DOM nodes, according to the DOM specification. Therefore, the XML parser treats each such sequence of whitespaces as a DOM node (of type TEXT);
To get rid of it, there are three approaches I can think of:
Associate the XML with a schema, and then use setValidating(true) along with setIgnoringElementContentWhitespace(true) on the DocumentBuilderFactory.
(Note: setIgnoringElementContentWhitespace will only work if the parser is in validating mode, which is why you must use setValidating(true))
Write an XSL to process all nodes, filtering out whitespace-only TEXT nodes.
Use Java code to do this: use XPath to find all whitespace-only TEXT nodes, iterate through them and remove each one from its parent (using getParentNode().removeChild()). Something like this would do (doc would be your DOM document object):
XPath xp = XPathFactory.newInstance().newXPath();
NodeList nl = (NodeList) xp.evaluate("//text()[normalize-space(.)='']", doc, XPathConstants.NODESET);
for (int i=0; i < nl.getLength(); ++i) {
Node node = nl.item(i);
node.getParentNode().removeChild(node);
}

I was able to fix this by using this code after removing all the old "path" nodes :
while( pathsElement.hasChildNodes() )
pathsElement.removeChild( pathsElement.getFirstChild() );
This will remove all the generated empty spaces in the XML file.
Special thanks to MadProgrammer for commenting with the helpful link mentioned above.

You could look at something like this if you only need to "clean" your xml quickly.
Then you could have a method like:
public static String cleanUp(String xml) {
final StringReader reader = new StringReader(xml.trim());
final StringWriter writer = new StringWriter();
try {
XmlUtil.prettyFormat(reader, writer);
return writer.toString();
} catch (IOException e) {
e.printStackTrace();
}
return xml.trim();
}
Also, to compare anche check differences, if you need it: XMLUnit

I faced the same problem, and I had no idea for the long time, but now, after this Brad's question and his own answer on his own question, I figured out where is the trouble.
I have to add my own answer, because Brad's one isn't really perfect, how Isaac said:
I wouldn't be a huge fan of blindly removing child nodes without knowing what they are
So, better "solution" (quoted because it is more likely workaround) is:
pathsElement.setTextContent("");
This completely removes useless blank lines. It is definitely better than removing all the child nodes. Brad, this should work for you too.
But, this is an effect, not the cause, and we got how to remove this effect, not the cause.
Cause is: when we call removeChild(), it removes this child, but it leaves indent of removed child, and line break too. And this indent_and_like_break is treated as a text content.
So, to remove the cause, we should figure out how to remove child and its indent. Welcome to my question about this.

There is a very simple way to get rid of the empty lines if using an DOM handling API (for example DOM4J):
place the text you want to keep in a variable(ie text)
set the node text to "" using node.setText("")
set the node text to text using node.setText(text)
et voila! there are no more empty lines. The other answers delineate very well how the extra empty lines in the xml output are actually extra nodes of type text.
This technique can be used with any DOM parsing system, so long as the name of the text setting function is changed to suit the one in your API, hence the way of representing it slightly more abstractly.
Hope this helps:)

When i used dom4j to remove some elements and i met the same question,the solution above not useful without adding some other required jars.Finally,i find out a simple solution only need to use JDK io pakage:
use BufferedReader to read the xml file and filter empty lines.
StringBuilder stringBuilder = new StringBuilder();
FileInputStream fis = new FileInputStream(outFile);
InputStreamReader isr = new InputStreamReader(fis);
BufferedReader br = new BufferedReader(isr);
String s;
while ((s = br.readLine()) != null) {
if (s.trim().length() > 0) {
stringBuilder.append(s).append("\n");
}
}
write the string to the xml file
OutputStreamWriter osw = new OutputStreamWriter(fou);
BufferedWriter bw = new BufferedWriter(osw);
String str = stringBuilder.toString();
bw.write(str);
bw.flush();
remember to close all the stream

In my case, I converted it to a string then just did a regex:
//save as String
StringWriter writer = new StringWriter();
StreamResult result = new StreamResult(writer);
tr.transform(new DOMSource(document), result);
strResult = writer.toString();
//remove empty lines
strResult = strResult.replaceAll("\\n\\s*\\n", "\n");

Couple of remarks:
1) When your are manipulating XML (removing elements / adding new one) I strongly advice you to use XSLT (and not DOM)
2) When you tranform a XML Document by XSLT (as you do in your save method), set the OutputKeys.INDENT to "no"
3) For simple post processing of your xml (removing white space, comments, etc.) you can use a simple SAX2 filter

DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
dbf.setIgnoringElementContentWhitespace(true);

I am using below code:
System.out.println("Start remove textnode");
i=0;
while (parentNode.getChildNodes().item(i)!=null) {
System.out.println(parentNode.getChildNodes().item(i).getNodeName());
if (parentNode.getChildNodes().item(i).getNodeName().equalsIgnoreCase("#text")) {
parentNode.removeChild(parentNode.getChildNodes().item(i));
System.out.println("text node removed");
}
i=i+1;
}

Very late answer, but maybe it is still helpful to someone.
I had this code in my class, where the document is built after transformation (Just like you):
TransformerFactory tFactory = TransformerFactory.newInstance();
Transformer transformer = tFactory.newTransformer();
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
Change the last line to
transformer.setOutputProperty(OutputKeys.INDENT, "no");

How to unformat xml file

I have a method which returns a String with a formatted xml. The method reads the xml from a file on the server and parses it into the string:
Esentially what the method currently does is:
private ServletConfig config;
InputStream xmlIn = null ;
xmlIn = config.getServletContext().getResourceAsStream(filename + ".xml") ;
String xml = IOUtils.toString(xmlIn);
IOUtils.closeQuietly(xmlIn);
return xml;
What I need to do is add a new input argument, and based on that value, continue returning the formatted xml, or return unformatted xml.
What I mean with formatted xml is something like:
<xml>
<root>
<elements>
<elem1/>
<elem2/>
<elements>
<root>
</xml>
And what I mean with unformatted xml is something like:
<xml><root><elements><elem1/><elem2/><elements><root></xml>
or:
<xml>
<root>
<elements>
<elem1/>
<elem2/>
<elements>
<root>
</xml>
Is there a simple way to do this?

Strip all newline characters with String xml = IOUtils.toString(xmlIn).replace("\n", ""). Or \t to keep several lines but without indentation.

if you are sure that the formatted xml like:
<xml>
<root>
<elements>
<elem1/>
<elem2/>
<elements>
<root>
</xml>
you can replace all group 1 in ^(\s*)< to "". in this way, the text in xml won't be changed.

an empty transformer with a parameter setting the indent params like so
public static String getStringFromDocument(Document dom, boolean indented) {
String signedContent = null;
try {
StringWriter sw = new StringWriter();
DOMSource domSource = new DOMSource(dom);
TransformerFactory tf = new TransformerFactoryImpl();
Transformer trans = tf.newTransformer();
trans = tf.newTransformer();
trans.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
trans.setOutputProperty(OutputKeys.INDENT, indented ? "yes" : "no");
trans.transform(domSource, new StreamResult(sw));
sw.flush();
signedContent = sw.toString();
} catch (TransformerException e) {
e.printStackTrace();
}
return signedContent;
}
works for me.
the key lies in this line
trans.setOutputProperty(OutputKeys.INDENT, indented ? "yes" : "no");

Try something like the following:
TransformerFactory factory = TransformerFactory.newInstance();
Transformer transformer = factory.newTransformer(
new StreamSource(new StringReader(
"<xsl:stylesheet version=\"1.0\"" +
" xmlns:xsl=\"http://www.w3.org/1999/XSL/Transform\">" +
"<xsl:output method=\"xml\" omit-xml-declaration=\"yes\"/>" +
" <xsl:strip-space elements=\"*\"/>" +
" <xsl:template match=\"#*|node()\">" +
" <xsl:copy>" +
" <xsl:apply-templates select=\"#*|node()\"/>" +
" </xsl:copy>" +
" </xsl:template>" +
"</xsl:stylesheet>"
))
);
Source source = new StreamSource(new StringReader("xml string here"));
StreamResult result = new StreamResult(System.out);
transformer.transform(source, result);
Instead of source being StreamSource in the second instance, it can also be DOMSource if you have an in-memory Document, if you want to modify the DOM before saving.
DOMSource source = new DOMSource(document);
To read an XML file into a Document object:
File file = new File("c:\\MyXMLFile.xml");
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(file);
doc.getDocumentElement().normalize();
Enjoy :)

If you fancy trying your hand with JAXB then the marshaller has a handy property for setting whether to format (use new lines and indent) the output or not.
JAXBContext jc = JAXBContext.newInstance(packageName);
Marshaller m = jc.createMarshaller();
m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
m.marshal(element, outputStream);
Quite an overhead to get to that stage though... perhaps a good option if you already have a solid xsd

You can:
1) remove all consecutive whitespaces (but not single whitespace) and then replace all >(whitespace)< by ><
applicable only if usefull content does not have multiple consecutive significant whitespaces
2) read it in some dom tree and serialize it using some nonpretty serialization
SAXReader reader = new SAXReader();
Reader r = new StringReader(data);
Document document = reader.read(r);
OutputFormat format = OutputFormat.createCompactFormat();
StringWriter sw = new StringWriter();
XMLWriter writer = new XMLWriter(sw, format);
writer.write(document);
String string = writer.toString();
3) use Canonicalization (but you must somehow explain to it that those whitespaces you want to remove are insignificant)

Kotlin.
An indentation will usually come after new line and formatted as one space or more. Hence, to make everything in the same column, we will replace all of the new lines, following one or more spaces:
xmlTag = xmlTag.replace("(\n +)".toRegex(), " ")

XML Transformation from Java Code

I am doing transformation of an XML File using XSL through Java code. I used this tutorial for the same. Now the problem is that the output file is created but it has no contents in it. I am also adding the code snippet. Kindly check it and tell me what am I missing :
TransformerFactory factory = TransformerFactory.newInstance();
System.out.println("In transform");
File temp = new File(xslFile);
if(temp.exists()){
System.out.println("File found");
}
StreamSource xsl = new StreamSource(temp);
Transformer transformer = factory.newTransformer(xsl);
temp = new File(xmlFile);
if(temp.exists()){
System.out.println("Found Again!!");
}
StreamSource xml = new StreamSource(temp);
temp = new File(outputFile);
if(temp.createNewFile()){
System.out.println("New File Created");
}
StreamResult output = new StreamResult(temp);
transformer.transform(xml, output);
Here, the xslFile, xmlFile and outputFile are string and passed as parameters to the method.

Try to declare three different variables, one for each file. Code will look clearer and you most likely will avoid some unexpected behaviour, as you don't know how is Transformer using those three references.