Java How to Indent XML Generated by Transformer

Question

I m using Java s built in XML transformer to take a DOM document and print out the resulting XML  The problem is that it isn t indenting the text at all despite having set the parameter  indent  explicitly   sample code  public class TestXML     public static void main String args    throws Exception     ByteArrayOutputStream s     Document d   DocumentBuilderFactory newInstance   newDocumentBuilder   newDocument      Transformer t   TransformerFactory newInstance   newTransformer       Element a b     a   d createElement  a      b   d createElement  b       a appendChild b      d appendChild a      t setParameter OutputKeys INDENT   yes       s   new ByteArrayOutputStream       t transform new DOMSource d  new StreamResult s       System out println new String s toByteArray              result   lt  xml version  1 0  encoding  UTF-8  standalone  no   gt  lt a gt  lt b  gt  lt  a gt    desired result   lt  xml version  1 0  encoding  UTF-8  standalone  no   gt   lt a gt    lt b  gt   lt  a gt    Thoughts

User · Answer

For me adding DOCTYPE PUBLIC worked   transformer setOutputProperty OutputKeys INDENT   yes    transformer setOutputProperty OutputKeys DOCTYPE PUBLIC  yes    transformer setOutputProperty   http   xml apache org xslt indent-amount    10

User · Answer

The following code is working for me with Java 7  I set the indent  yes  and indent-amount  2  on the transformer  not the transformer factory  to get it working   TransformerFactory tf   TransformerFactory newInstance    Transformer t   tf newTransformer    t setOutputProperty   http   xml apache org xslt indent-amount    2    t setOutputProperty OutputKeys INDENT   yes    t transform source  result      mabac s solution to set the attribute didn t work for me  but  lapo s comment proved helpful

User · Answer

If you want the indentation  you have to specify it to the TransformerFactory   TransformerFactory tf   TransformerFactory newInstance    tf setAttribute  indent-number   new Integer 2    Transformer t   tf newTransformer

User · Answer

I used the Xerces  Apache  library instead of messing with Transformer   Once you add the library add the code below   OutputFormat format   new OutputFormat document   format setLineWidth 65   format setIndenting true   format setIndent 2   Writer outxml   new FileWriter new File  out xml     XMLSerializer serializer   new XMLSerializer outxml  format   serializer serialize document

User · Answer

Neither of the suggested solutions worked for me  So I kept on searching for an alternative solution  which ended up being a mixture of the two before mentioned and a third step    set the indent-number into the transformerfactory  enable the indent in the transformer wrap the otuputstream with a writer  or bufferedwriter       1  TransformerFactory tf   TransformerFactory newInstance    tf setAttribute  indent-number   new Integer 2        2  Transformer t   tf newTransformer    t setOutputProperty OutputKeys INDENT   yes        3  t transform new DOMSource doc   new StreamResult new OutputStreamWriter out   utf-8       You must do  3  to workaround a  buggy  behavior of the xml handling code   Source  johnnymac75   http   bugs sun com bugdatabase view bug do bug id 6296446   If I have cited my source incorrectly please let me know

User · Answer

import com sun org apache xml internal serializer OutputPropertiesFactory  transformer setOutputProperty OutputPropertiesFactory S KEY INDENT AMOUNT   2

User · Answer

You need to enable  INDENT  and set the indent amount for the transformer   t setOutputProperty OutputKeys INDENT   yes    t setOutputProperty   http   xml apache org xslt indent-amount    2      Update     Reference   How to strip whitespace-only text nodes from a DOM before serialization    Many thanks to all members especially  marc-novakowski   james-murty and  saad

[java] Java: How to Indent XML Generated by Transformer

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