my code is:

-----------------------------------------------------
 public static boolean enDeCrypt(String keyStr, File fin, File fout) {
   try {
    FileInputStream in = new FileInputStream(fin);
     FileOutputStream out = new FileOutputStream(fout);
     Cipher desCipher = Cipher.getInstance("AES");
     desCipher.init(Cipher.ENCRYPT_MODE,
                           new SecretKeySpec(keyStr.getBytes("UTF-8"),
"AES"));
     CipherOutputStream cos = new CipherOutputStream(out, desCipher);
     byte[] enBuffer = new byte[4096];
     int n;
     while ( (n = in.read(enBuffer)) != -1) {
       cos.write(enBuffer, 0, n);
     }
     cos.close();
   }
   catch (Exception e) {
     e.printStackTrace();
     return false;
   }
   return true;
 }
-----------------------------------------------------

but it throw exception:
java.security.InvalidKeyException: Illegal key size or default
parameters
I used a 192-bit key

if I change the key's length, it will throw excepion:
java.security.InvalidKeyException: Invalid AES key length: 272
It seemed that it is not the problem about the length of the key

how can I fix it

Thank you very much in advance