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copied!<p>The trick is to "mark" the Reader. If your reader does not support marking you can wrap it in a BufferedReader which does:</p> <ul> <li><a href="http://download.oracle.com/javase/6/docs/api/java/io/BufferedReader.html#markSupported%28%29" rel="nofollow">http://download.oracle.com/javase/6/docs/api/java/io/BufferedReader.html#markSupported%28%29</a></li> </ul> <p><strong>OPTION #1 - Check for BOM and Remove It</strong></p> <p>I believe my original code was writing the BOM incorrectly. The source code below makes more sense:</p> <pre><code>import java.io.*; import javax.xml.transform.Transformer; import javax.xml.transform.TransformerFactory; import javax.xml.transform.stream.StreamResult; import javax.xml.transform.stream.StreamSource; public class Demo { private static char[] UTF32BE = {0x00, 0x00, 0xFE, 0xFF}; private static char[] UTF32LE = {0xFF, 0xFE, 0x00, 0x00}; private static char[] UTF16BE = {0xFE, 0xFF}; private static char[] UTF16LE = {0xFF, 0xFE}; private static char[] UTF8 = {0xEF, 0xBB, 0xBF}; public static void main(String[] args) throws Exception { // Create an XML document with a BOM FileOutputStream fos = new FileOutputStream("bom.xml"); writeBOM(fos, UTF16LE); OutputStreamWriter oswUTF8 = new OutputStreamWriter(fos, "UTF-8"); oswUTF8.write("<root/>"); oswUTF8.close(); // Create a Source based on a Reader to simulate source.getRequest() StreamSource attachment = new StreamSource(new FileReader(new File("bom.xml"))); // Wrap reader in BufferedReader so it will support marking Reader reader = new BufferedReader(attachment.getReader()); // Remove the BOM removeBOM(reader); TransformerFactory tf = TransformerFactory.newInstance(); Transformer t = tf.newTransformer(); t.transform(new StreamSource(reader), new StreamResult(System.out)); } private static void writeBOM(OutputStream os, char[] bom) throws Exception { for(int x=0; x<bom.length; x++) { os.write((byte) bom[x]); } } private static void removeBOM(Reader reader) throws Exception { if(removeBOM(reader, UTF32BE)) { return; } if(removeBOM(reader, UTF32LE)) { return; } if(removeBOM(reader, UTF16BE)) { return; } if(removeBOM(reader, UTF16LE)) { return; } if(removeBOM(reader, UTF8)) { return; } } private static boolean removeBOM(Reader reader, char[] bom) throws Exception { int bomLength = bom.length; reader.mark(bomLength); char[] possibleBOM = new char[bomLength]; reader.read(possibleBOM); for(int x=0; x<bomLength; x++) { if(bom[x] != possibleBOM[x]) { reader.reset(); return false; } } return true; } } </code></pre> <p><strong>OPTION #2 - Find '<' and Advance Reader to that Point</strong></p> <p>Read until you hit the '<' leveraging mark/reset:</p> <pre><code>import java.io.*; import javax.xml.transform.Transformer; import javax.xml.transform.TransformerFactory; import javax.xml.transform.stream.StreamResult; import javax.xml.transform.stream.StreamSource; public class Demo2 { private static char[] UTF32BE = {0x00, 0x00, 0xFE, 0xFF}; private static char[] UTF32LE = {0xFF, 0xFE, 0x00, 0x00}; private static char[] UTF16BE = {0xFE, 0xFF}; private static char[] UTF16LE = {0xFF, 0xFE}; private static char[] UTF8 = {0xEF, 0xBB, 0xBF}; public static void main(String[] args) throws Exception { // Create an XML document with a BOM FileOutputStream fos = new FileOutputStream("bom.xml"); writeBOM(fos, UTF16BE); OutputStreamWriter oswUTF8 = new OutputStreamWriter(fos, "UTF-8"); oswUTF8.write("<root/>"); oswUTF8.close(); // Create a Source based on a Reader to simulate source.getRequest() StreamSource attachment = new StreamSource(new FileReader(new File("bom.xml"))); // Wrap reader in BufferedReader so it will support marking Reader reader = new BufferedReader(attachment.getReader()); // Remove the BOM removeBOM(reader); TransformerFactory tf = TransformerFactory.newInstance(); Transformer t = tf.newTransformer(); t.transform(new StreamSource(reader), new StreamResult(System.out)); } private static void writeBOM(OutputStream os, char[] bom) throws Exception { for(int x=0; x<bom.length; x++) { os.write((byte) bom[x]); } } private static Reader removeBOM(Reader reader) throws Exception { reader.mark(1); char[] potentialStart = new char[1]; reader.read(potentialStart); if('<' == potentialStart[0]) { reader.reset(); return reader; } else { return removeBOM(reader); } } } </code></pre>

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