Copy a Directory in Java

/*from  w  w w .ja  va  2s  . co m*/
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class Main {
  public static void main(String[] argv) throws Exception {
    copyDirectory(new File("srcDir"), new File("dstDir"));
  }

  public static void copyDirectory(File srcDir, File dstDir) throws IOException {
    if (srcDir.isDirectory()) {
      if (!dstDir.exists()) {
        dstDir.mkdir();
      }

      String[] children = srcDir.list();
      for (int i = 0; i < children.length; i++) {
        copyDirectory(new File(srcDir, children[i]), new File(dstDir, children[i]));
      }
    } else {

      copyFile(srcDir, dstDir);
    }
  }

  static void copyFile(File src, File dst) throws IOException {
    InputStream in = new FileInputStream(src);
    OutputStream out = new FileOutputStream(dst);

    // Transfer bytes from in to out
    byte[] buf = new byte[1024];
    int len;
    while ((len = in.read(buf)) > 0) {
      out.write(buf, 0, len);
    }
    in.close();
    out.close();
  }

}