Using JFileChooser

public class FileSelector {

 public static File showOpenDlg(Component parent, String[] exts){
 
  JFileChooser chooser = new JFileChooser();
 
  chooser.setFileFilter(new FileFilterImpl(exts));
 
  chooser.setCurrentDirectory(new File(System.getProperty("user.dir")));
 
  int returnVal = chooser.showOpenDialog(parent);

     if(returnVal == JFileChooser.APPROVE_OPTION) {
      return chooser.getSelectedFile();
     }
    
     return null;
 }
 
 public static File showSaveDlg(Component parent, String[] exts, String displayName){
 
  JFileChooser chooser = new JFileChooser();
 
  chooser.setFileFilter(new FileFilterImpl(exts));
 
  chooser.setCurrentDirectory(new File(System.getProperty("user.dir")));
 
  chooser.setSelectedFile(new File(displayName));
    
  int returnVal = chooser.showSaveDialog(parent);

     if(returnVal == JFileChooser.APPROVE_OPTION) {
      return chooser.getSelectedFile();
     }    
     return null;
 }
}

public class FileFilterImpl extends FileFilter{
 
 public String[] exts;
 
 public FileFilterImpl(String[] exts){
  this.exts = exts;
 }

 public boolean accept(File f)
 {
  if (f.isDirectory()) {
   return true;
  }
 
  String extension = getExtension(f);
 
  if(extension == null)
   return false;
 
  for(int i=0; i < exts.length; i++){
   
   if(extension.toLowerCase().equals(exts[i]))
   return true;
   
  }

  return false;
 }

 public String getDescription(){
 
  StringBuffer sb = new StringBuffer();
 
  for(int i=0; i < exts.length; i++)
  {
   if(i == (exts.length-1))
    sb.append(exts[i]);
   else
    sb.append(exts[i] + ", ");
  }
   return sb.toString()+" File Selection";
 }

 public String getExtension(File f) {
        String ext = null;
        String s = f.getName();
        int i = s.lastIndexOf('.');

        if (i > 0 &&  i < s.length() - 1) {
            ext = s.substring(i+1).toLowerCase();
        }
        return ext;
    }

 public String getTypeDescription(File f) {
 
  String extension = getExtension(f);
  String type = null;
 
  if (extension != null) {
   
   for(int i=0; i < exts.length; i++){
    if(exts[i].toLowerCase().equals(extension))
     return extension.toUpperCase() + " File";
   }
  }
 
  return type;
 }

}