java实现CRC16校验码生成

public static String crc16(String gprsstr) {
try {
int crc;
int strlength, r;
byte sbit;
int tc;
strlength = gprsstr.length();
byte[] data = gprsstr.getBytes();
crc = 0x0000FFFF;
for (int i = 0; i < strlength; i++) {
tc = (int) (crc >>> 8);
crc = (int) (tc ^ data[i]);
for (r = 0; r < 8; r++) {
sbit = (byte) (crc & 0x00000001);
crc >>>= 1;
if (sbit != 0)
crc ^= 0x0000A001;
}
}
return Integer.toHexString(crc);
} catch (Exception ex) {
return "";
}
}