copy file


How do I copy file from one directory to another

thanks ASA.

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this will help u

                                    public class CopyFile {
                                     public static void main(String args[])
                                    String newLine = System.getProperty("line.separator");
                                    FileWriter fw = null;
                                    FileReader fr = null;
                                    BufferedReader br = null;
                                    BufferedWriter bw = null;
                                    File source = null;

                                    if (args.length < 2)
                                      System.out.println("Command Syntax: CopyFile <source>
                                    <dest>\n\n<source>\tThe source file name (path
                                    optional)\n<dest>\t\tThe destination file name (path optional)");
                                    else {
                                    try {
                                    fr = new FileReader(args[0]);
                                    fw = new FileWriter(args[1]);
                                    br = new BufferedReader(fr);
                                    bw = new BufferedWriter(fw);

                                    /* Determine the size of the buffer to allocate */
                                    source = new File(args[0]);

                                    int fileLength = (int) source.length();

                                    char charBuff[] = new char[fileLength];

                                    while (,0,fileLength) != -1)
                                    catch(FileNotFoundException fnfe){
                                    System.out.println(args[0] + " does not exist!");
                                    catch(IOException ioe) {
                                    System.out.println("Error reading/writing files!");
                                    finally {
                                    try {
                                    if (br != null)

                                    if (bw != null)
                                    catch(IOException ioe)


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just a note: it seems to me better to use directly Input/OutputStreams and byte[], instead of Reader&Writers & char[] ...
this is another solution

   public class FileCopy {
   public static void copy(String source_name, String dest_name)
   throws IOException
                       File source_file = new File(source_name);
                       File destination_file = new File(dest_name);
                       FileInputStream source = null;
                       FileOutputStream destination = null;
                       byte[] buffer;
                       int bytes_read;
                       try {
                         // First make sure the specified source file
                        // exists, is a file, and is readable.
                        if (!source_file.exists() || !source_file.isFile())
 throw new FileCopyException("FileCopy: no such source                            file: " +                                                source_name);
 if (!source_file.canRead())
  throw new FileCopyException("FileCopy: source file " +
                                                                    "is unreadable: " + source_name);
      // If the destination exists, make sure it is a writeable file
      // and ask before overwriting it.  If the destination doesn't
      // exist, make sure the directory exists and is writeable.
                        if (destination_file.exists()) {
                                 if (destination_file.isFile()) {
                   DataInputStream in = new               DataInputStream(;
                                                        String response;
                                                        if (!destination_file.canWrite())
                                                            throw new FileCopyException("FileCopy:
                                    destination " +
                                                                            "file is unwriteable: " + dest_name);
                                                        System.out.print("File " + dest_name +
                                                                 " already exists.  Overwrite? (Y/N): ");
                                                        response = in.readLine();
                                                        if (!response.equals("Y") && !response.equals("y"))
                                                            throw new FileCopyException("FileCopy: copy
                                                        throw new FileCopyException("FileCopy: destination " 
                                                                        + "is not a file: " +  dest_name);
                                                else {
                                                    File parentdir = parent(destination_file);
                                                    if (!parentdir.exists())
                                                        throw new FileCopyException("FileCopy: destination " 
                                                                        + "directory doesn't exist: " +
                                                    if (!parentdir.canWrite())
                                                        throw new FileCopyException("FileCopy: destination " 
                                                                        + "directory is unwriteable: " +
                                                // If we've gotten this far, then everything is okay; we can
                                                // copy the file.
                                                source = new FileInputStream(source_file);
                                                destination = new FileOutputStream(destination_file);
                                                buffer = new byte[1024];
                                                while(true) {
                                                    bytes_read =;
                                                    if (bytes_read == -1) break;
                                                    destination.write(buffer, 0, bytes_read);
                                            // No matter what happens, always close any streams we've
                                            finally {
                                                if (source != null)
                                                    try { source.close(); } catch (IOException e) { ; }
                                                if (destination != null)
                                                    try { destination.close(); } catch (IOException e) { ; }
                                        // File.getParent() can return null when the file is specified
                                        // a directory or is in the root directory.  
                                        // This method handles those cases.
                                        private static File parent(File f) {
                                            String dirname = f.getParent();
                                            if (dirname == null) {
                                                if (f.isAbsolute()) return new File(File.separator);
                                                else return new File(System.getProperty("user.dir"));
                                            return new File(dirname);
                                        public static void main(String[] args) {
                                            if (args.length != 2)
                                                System.err.println("Usage: java FileCopy " +
                                                           "<source file> <destination file>");
                                            else {
                                                try { copy(args[0], args[1]); }
                                                catch (IOException e) {
                                    System.err.println(e.getMessage()); }

                                    class FileCopyException extends IOException {
                                        public FileCopyException(String msg) { super(msg); }

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     static public void execCmd(String[] cmdParam) throws Exception {
            StringBuffer cmd = new StringBuffer();
            cmd.append(cmdParam[0]).append(" ");

            for(int i = 1; i<cmdParam.length; i++) {
                  cmd.append(cmdParam[i]).append(" ");

            Process pr = Runtime.getRuntime().exec(cmd.toString());
            Log.logMsg("Exit Value for :" + cmd + " is " + pr.exitValue());

call this method lie execCmd(" cmd.exe /c copy source destinaltion")

hope this helps..

The first solution hangs on zero-length files. With this change it doesn't.

int len;
while ((len =,0,fileLength)) > 0)                         bw.write(charBuff,0,len);
Using the new Java IO, this becomes very fast and simple:

/** Fast & simple file copy. */
public static void copy(File source, File dest) throws IOException {
      FileChannel in = null, out = null;
      try {            
            in = new FileInputStream(source).getChannel();
            out = new FileOutputStream(dest).getChannel();

            long size = in.size();
            MappedByteBuffer buf =, 0, size);


      } finally {
            if (in != null)            in.close();
            if (out != null)      out.close();

This will even work if your files are larger than physical memory, but it may swap out a lot of pages you'd have rather kept in memory.
MappedByteBuffer keeps the input file open even after proper closing of channel...
Here is the way to solve this..

in = new FileInputStream(source).getChannel();
out = new FileOutputStream(dest).getChannel();
in.transferTo( 0, in.size(), out);

that's it :)
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