private static String hashPath(String path) {
byte[] data=path.getBytes();
SHA1Digest digest=new SHA1Digest();
digest.update(data, 0, data.length);
byte[] result=new byte[digest.getDigestSize()];
digest.doFinal(result, 0);
String ret=null;
ret=new String(Base64.encode(result));
return ret;
}