Format XML data when writing to a file

Question

Hi,
I am trying to write runtime data (XML) to a file. I am doign the following to write to the file:
public void saveFile() throws Exception {
try {
TransformerFactory transformerFactory =
TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
DOMSource source = new DOMSource(doc);
OutputStream output = new FileOutputStream(XMLFile);
StreamResult result = new StreamResult();
transformer.transform(source, result);
output.flush();
output.close();
} catch (Exception x) {
throw x;
The output from the above code is a clutter of elements. All the elements are on the same line some times.
1) How can I format the output? (Indent the elements in the file)
Is there a way to achieve this?
Sometimes, I see a square character at the end of some lines. I thought the output file is corrupt because of this character. But it does not seem to be a problem.
2) How do I avoid this character?

Answer 1

Also, I am planning on using xpath in conjunction with DOM. However I read on one of the websites not to use too many xpath queries. I am using jdk 1.5.
Is it tight. My code might have to be run many times. Is the following ok?
or should I eliminate xpath and do my own traversing. I am concerned about runtime performance if I have to continue to update the xml file frequently.
public Element getMatchingNode(MyAttributes attr) throws Exception {
try {
File myFile = new File(XMLFile);
if (myFile.exists()) {
System.out.println(XMLFile + " File exists");
XPathFactory factory = XPathFactory.newInstance();
XPath xPath = factory.newXPath();
InputSource inputSource =
new InputSource(new FileInputStream(myFile));
String matchingString = this.getMatchingString(attr);
Element module =
(Element)xPath.evaluate("/" + TEST_TAG +
"/" +
TEST_TAG2 +
"/" +
DETAIL +
matchingString,
inputSource,
XPathConstants.NODE);
return module;
} else
return null;
} catch (Exception x) {
throw x;
private String getMatchingString(MyAttributes attrs){
StringBuffer buffer = new StringBuffer();
for (Enumeration e=attrs.keys(); e.hasMoreElements();){
String attribute = (String)e.nextElement();
String value = attrs.get(attribute);
buffer.append("[@" + attribute + "=" + "'" + value + "']");
return buffer.toString();
}