JAVA中GBK转UTF-8

public static String getUTF8StringFromGBKString(String gbkStr) {
  try {
   return new String(getUTF8BytesFromGBKString(gbkStr), "UTF-8");
  } catch (UnsupportedEncodingException e) {
   throw new InternalError();
  }
 }

 public static byte[] getUTF8BytesFromGBKString(String gbkStr) {
  int n = gbkStr.length();
  byte[] utfBytes = new byte[3 * n];
  int k = 0;
  for (int i = 0; i < n; i++) {
   int m = gbkStr.charAt(i);
   if (m < 128 && m >= 0) {
    utfBytes[k++] = (byte) m;
    continue;
   }
   utfBytes[k++] = (byte) (0xe0 | (m >> 12));
   utfBytes[k++] = (byte) (0x80 | ((m >> 6) & 0x3f));
   utfBytes[k++] = (byte) (0x80 | (m & 0x3f));
  }
  if (k < utfBytes.length) {
   byte[] tmp = new byte[k];
   System.arraycopy(utfBytes, 0, tmp, 0, k);
   return tmp;
  }
  return utfBytes;
 }