全角、半角の変換

String toHalf(String str){
  StringBuffer sb = new StringBuffer();
  for(int i = 0; i < str.length(); i++){
    sb.append(toHalf((int)str.charAt(i)));
  }
  return sb.toString();
}

char toHalf(int c){
  if ( c >= 65281 && c <= 65374){
    c -= 65248;
  }
  return (char)c;
}

String toFull(String str){
  StringBuffer sb = new StringBuffer();
  for(int i = 0; i < str.length(); i++){
    sb.append(toFull((int)str.charAt(i)));
  }
  return sb.toString();
}

char toFull(int c){
  if ( c >= 33 && c <= 126){
    c += 65248;
  }
  return (char)c;
}