Delete the specified character in a text file using RandomAccessFile

Question

Hi All,
I have an invalid XML file which contains Return characters at the end of each line. I need to delete these return characters so the file becomes valid.
Does anybody have any idea how this could be done using RandomAccessFile?
I found joop_eggen's posting in this forum, modified it just a little and wanted to use it, but since the replacement character is "" (blank) it does not do what I need to.
The XML file looks like this:
<?xml version="1.0"?>
<EPMSObject>
<EPMSRecord><facilityname>KT0</facilityname><date_time>2007-06-01T00:00:00</date_time><devicetype>RPP</devicetype><devicename>RPP1A1_001.BCMF</devicename><meter>BCMF</meter><ckt_01_current>4.136000000000000e+000</ckt_01_current><ckt_02_current>0.000000000000000e+000</ckt_02_current><ckt_03_current>5.521000000000000e+000</ckt_03_current><ckt_04_current>0.000000000000000e+000</ckt_04_current><ckt_05_current>5.880000000000000e+000</ckt_05_current><ckt_06_current>0.000000000000000e+000</ckt_06_current><ckt_07_current>4.086000000000000e+000</ckt_07_current><ckt_08_current>0.000000000000000e+000</ckt_08_current><ckt_09_current>4.994000000000000e+000</ckt_09_current><ckt_10_current>0.000000000000000e+000</ckt_10_current><ckt_11_current>4.374000000000000e+000</ckt_11_current><ckt_12_current>0.000000000000000e+000</ckt_12_current><ckt_13_current>4.314000000000000e+000</ckt_13_current><ckt_14_current>0.000000000000000e+000</ckt_14_current><ckt_15_current>4.112000000000000e+000</ckt_15_current><ckt_16_current>0.000000000000000e+000</ckt_16_current><ckt_17_current>4.287000000000000e+000</ckt_17_current><ckt_18_current>0.000000000000000e+000</ckt_18_current><ckt_19_current>4.254000000000000e+000</ckt_19_current><ckt_20_current>0.000000000000000e+000</ckt_20_current><ckt_21_current>3.970000000000000e+000</ckt_21_current><ckt_22_current>0.000000000000000e+000</ckt_22_current><ckt_23_current>5.640000000000000e+000</ckt_23_current><ckt_24_current>0.000000000000000e+000</ckt_24_current><ckt_25_current>7.123000000000000e+000</ckt_25_current><ckt_26_current>0.000000000000000e+000</ckt_26_current><ckt_27_current>5.118000000000000e+000</ckt_27_current><ckt_28_current>0.000000000000000e+000</ckt_28_current><ckt_29_current>6.094000000000000e+000</ckt_29_current><ckt_30_current>0.000000000000000e+000</ckt_30_current><ckt_31_current>0.000000000000000e+000</ckt_31_current><ckt_32_current>0.000000000000000e+000</ckt_32_current><ckt_33_current>0.000000000000000e+000</ckt_33_current><ckt_34_current>0.000000000000000e+000</ckt_
34_current><ckt_35_current>0.000000000000000e+000</ckt_35_current><ckt_36_current>0.000000000000000e+000</ckt_36_current><ckt_37_current>0.000000000000000e+000</ckt_37_current><ckt_38_current>0.000000000000000e+000</ckt_38_current><ckt_39_current>0.000000000000000e+000</ckt_39_current><ckt_40_current>0.000000000000000e+000</ckt_40_current><ckt_41_current>0.000000000000000e+000</ckt_41_current><ckt_42_current>0.000000000000000e+000</ckt_42_current></EPMSRecord>
</EPMSObject>
Here is joop_eggen's code:
import java.io.*;
import java.nio.*;
import java.nio.channels.*;
public class Patch {
  private static byte[] sought;
  private static byte[] replacement;
  private static boolean matches(MappedByteBuffer bb, int pos) {
    for (int j = 0; j < sought.length; ++j)
      if (sought[j] != bb.get(pos + j))
        return false;
    return true;
  private static void replace(MappedByteBuffer bb, int pos) {
    for (int j = 0; j < sought.length; ++j)
      byte b = (j < replacement.length)? replacement[j] : (byte)' ';
      bb.put(pos + j, b);
  private static void searchAndReplace(MappedByteBuffer bb, int sz) {
    int replacementsCount = 0;
    for (int pos = 0; pos <= sz - sought.length; ++pos)
      if (matches(bb, pos)) {
        replace(bb, pos);
        pos += sought.length - 1;
        ++replacementsCount;
    System.out.println("" + replacementsCount + " replacements done.");
    // Search for occurrences of the input pattern in the given file
    private static void patch(File f) throws IOException {
    // Open the file and then get a channel from the stream
    RandomAccessFile raf = new RandomAccessFile(f, "rw"); // "rws", "rwd"
    FileChannel fc = raf.getChannel();
    // Get the file's size and then map it into memory
    int sz = (int)fc.size();
    MappedByteBuffer bb = fc.map(FileChannel.MapMode.READ_WRITE, 0, sz);
    searchAndReplace(bb, sz);
    bb.force(); // Write back to file, like "flush()"
    // Close the channel and the stream
    raf.close();
    public static void main(String[] args) {
    String E_O_L;
    E_O_L = System.getProperty( "line.separator" );
    if (args.length == 0)
      args = new String[] { E_O_L, "", "C:\\GTI\\EPMSRecords.xml" };
    if (args.length < 3) {
      System.err.println("Usage: java Patch sought replacement file...");
      return;
    sought = args[0].getBytes();
    replacement = args[1].getBytes();
    //if (sought.length != replacement.length) {
      // Better build-in some support for padding with blanks.
      //System.err.println("Usage: sought (" + args[0] + ") and replacement (" + args[1] + ") must have same length");
      //return;
    for (int i = 2; i < args.length; i++) {
      File f = new File(args);
try {
patch(f);
} catch (IOException x) {
System.err.println(f + ": " + x);
Thank you,
Sinan Topuz

Answer 1

Thank you all.
Here is what I have right now and it works very well. It takes a couple of seconds to generate the second file and that satisfies me. I took the code sabre150 posted in this forum and changed it just a little bit, so thanks to him.
I hope this helps someone.
Sinan
import java.io.*;
public class SearchReplace{
    public static void main(String[] args){
        if(null == args || args.length < 2) {
           System.err.println("\nUsage: java <inputFileFullPath> <OutputFileFullPath> \nExample: java C:\\GTI\\Epmsrecord.xml C:\\GTI\\EpmsrecordNEW.xml");
           System.exit(1);
        Reader reader = null;
        Writer writer = null;
        try{
            char cr;
            char lf;
            char sp;
            int  indx;
            cr = '\r';
            lf = '\n';
            sp = ' ';
            indx = 0;
            reader = new FileReader(args[0]);
            writer = new FileWriter(args[1]);
            for (int ch = ' '; (ch = reader.read()) != -1;){
                indx++;
                if ( indx > 15 ) {      // Skip the first space character in <?xml version="1.0"?> otherwise the file becomes invaild!
                    if (ch != cr && ch != lf ) {
                        writer.write(ch);
                }else{
                    writer.write(ch);
            System.out.println("\nFile " + args[1] + " has been successfully created.");
        }catch(FileNotFoundException fnfe){
            System.out.println("\nError : File " + args[0] + " not found. Please make sure it exists and you have rights to access to it.");
        }catch (IOException e) {
            System.err.println("Caught IOException: " +  e.getMessage());
        }finally {
            try {
                if ( reader!=null ) {
                    reader.close();
                if ( writer!=null ) {
                    writer.close();
            }catch (IOException e){
                System.err.println("I/O error occured while trying to close the files.");
}