我的程序属于通信双方中的接收端，根据发送端发送过来的CRC校验码，进行一下CRC校验，接收端可以用下面的方法判断是否正确吗，哪位指点一下？private static String mkCrc16(String str) {
CRC16 crc16 = new CRC16();
byte[] b = str.getBytes();
for (int i = 0; i < b.length; i++)
crc16.update(b[i]);
return Integer.toHexString(crc16.value);
} private static String mkCrc(String string) throws Exception { CRC32 crc32 = new CRC32();
crc32.update(string.getBytes()); return Long.toHexString(crc32.getValue());
}
public class CRCUtil {
public static final int evalCRC16(byte[] data) {
int crc = 0xFFFF;
for (int i = 0; i < data.length; i++) {
crc = (data[i] << 8) ^ crc;
for (int j = 0; j < 8; ++j)
if ((crc & 0x8000) != 0)
crc = (crc << 1) ^ 0x1021;
else
crc <<= 1;
}
return (crc ^ 0xFFFF) & 0xFFFF;
}
}
CRC16 crc16 = new CRC16();
byte[] b = str.getBytes();
for (int i = 0; i < b.length; i++)
crc16.update(b[i]);
return Integer.toHexString(crc16.value);
} private static String mkCrc(String string) throws Exception { CRC32 crc32 = new CRC32();
crc32.update(string.getBytes()); return Long.toHexString(crc32.getValue());
}
public class CRCUtil {
public static final int evalCRC16(byte[] data) {
int crc = 0xFFFF;
for (int i = 0; i < data.length; i++) {
crc = (data[i] << 8) ^ crc;
for (int j = 0; j < 8; ++j)
if ((crc & 0x8000) != 0)
crc = (crc << 1) ^ 0x1021;
else
crc <<= 1;
}
return (crc ^ 0xFFFF) & 0xFFFF;
}
}
第一种:public class CRC16 {
private short[] crcTable = new short[256];
private int gPloy = 0x8005; // 生成多项式 public CRC16() {
computeCrcTable();
} private short getCrcOfByte(int aByte) {
int value = aByte << 8; for (int count = 7; count >= 0; count--) {
if ((value & 0x8000) != 0) { // 高第16位为1，可以按位异或
value = (value << 1) ^ gPloy;
} else {
value = value << 1; // 首位为0，左移
} }
value = value & 0xFFFF; // 取低16位的值
return (short)value;
} /*
* 生成0 - 255对应的CRC16校验码
*/
private void computeCrcTable() {
for (int i = 0; i < 256; i++) {
crcTable[i] = getCrcOfByte(i);
}
} public short getCrc(byte[] data) {
int crc = 0;
int length = data.length;
for (int i = 0; i < length; i++) {
crc = ((crc & 0xFF) << 8) ^ crcTable[(((crc & 0xFF00) >> 8) ^ data[i]) & 0xFF];
}
crc = crc & 0xFFFF;
return (short)crc;
}
}
public final class CodecUtil {
static CRC16 crc16 = new CRC16(); private CodecUtil() {
} public static byte[] short2bytes(short s) {
byte[] bytes = new byte[2];
for (int i = 1; i >= 0; i--) {
bytes[i] = (byte)(s % 256);
s >>= 8;
}
return bytes;
} public static short bytes2short(byte[] bytes) {
short s = (short)(bytes[1] & 0xFF);
s |= (bytes[0] << 8) & 0xFF00;
return s;
} /*
* 获取crc校验的byte形式
*/
public static byte[] crc16Bytes(byte[] data) {
return short2bytes(crc16Short(data));
} /*
* 获取crc校验的short形式
*/
public static short crc16Short(byte[] data) {
return crc16.getCrc(data);
} public static void main(String[] args) {
byte[] test = new byte[] {0, 1, 2, 3, 4};
byte[] crc = crc16Bytes(test); byte[] testc = new byte[test.length + 2];
for (int i = 0; i < test.length; i++) {
testc[i] = test[i];
}
testc[test.length] = crc[0];
testc[test.length + 1] = crc[1]; System.out.println(crc16Short(testc));
}
}
第二种： private static int parse(char c) {
if (c >= 'a'){
return (c - 'a' + 10) & 0x0f;
} if (c >= 'A'){
return (c - 'A' + 10) & 0x0f;
} return (c - '0') & 0x0f;
} public static byte[] HexString2Bytes(String hexstr) {
byte[] b = new byte[hexstr.length() / 2];
int j = 0; for (int i = 0; i < b.length; i++) {
char c0 = hexstr.charAt(j++);
char c1 = hexstr.charAt(j++); b[i] = (byte) ((parse(c0) << 4) | parse(c1));
} return b;
}
第三种： public static final String evalCRC16(byte[] data) {
int crc = 0xFFFF;
for (int i = 0; i < data.length; i++) {
crc = (data[i] << 8) ^ crc;
for (int j = 0; j < 8; ++j){
if ((crc & 0x8000) != 0)
crc = (crc << 1) ^ 0x1021;
else
crc <<= 1;
}
}
return Integer.toHexString((crc ^ 0xFFFF) & 0xFFFF);
}
第四种：public static String mkCrc16(byte[] b) {
CRC16 crc16 = new CRC16();
for (int i = 0; i < b.length; i++){
crc16.update(b[i]);
}
return Integer.toHexString(crc16.value);
}
第五种:public static String crcTable(byte[] bytes) {
int[] table = {
0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40,
0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841,
0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40,
0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41,
0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641,
0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040,
0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240,
0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441,
0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41,
0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840,
0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41,
0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40,
0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640,
0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041,
0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240,
0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441,
0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41,
0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840,
0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41,
0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40,
0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640,
0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041,
0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241,
0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440,
0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40,
0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841,
0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40,
0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41,
0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641,
0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040,
}; int crc = 0x0000;
for (byte b : bytes) {
crc = (crc >>> 8) ^ table[(crc ^ b) & 0xff];
} return Integer.toHexString(crc);
}
第六种：public static String getCRC16( byte[] data){
int CRCTABLE[]={
0xF078,0xE1F1,0xD36A,0xC2E3,0xB65C,0xA7D5,0x954E,0x84C7,
0x7C30,0x6DB9,0x5F22,0x4EAB,0x3A14,0x2B9D,0x1906,0x088F,
0xE0F9,0xF170,0xC3EB,0xD262,0xA6DD,0xB754,0x85CF,0x9446,
0x6CB1,0x7D38,0x4FA3,0x5E2A,0x2A95,0x3B1C,0x0987,0x180E,
0xD17A,0xC0F3,0xF268,0xE3E1,0x975E,0x86D7,0xB44C,0xA5C5,
0x5D32,0x4CBB,0x7E20,0x6FA9,0x1B16,0x0A9F,0x3804,0x298D,
0xC1FB,0xD072,0xE2E9,0xF360,0x87DF,0x9656,0xA4CD,0xB544,
0x4DB3,0x5C3A,0x6EA1,0x7F28,0x0B97,0x1A1E,0x2885,0x390C,
0xB27C,0xA3F5,0x916E,0x80E7,0xF458,0xE5D1,0xD74A,0xC6C3,
0x3E34,0x2FBD,0x1D26,0x0CAF,0x7810,0x6999,0x5B02,0x4A8B,
0xA2FD,0xB374,0x81EF,0x9066,0xE4D9,0xF550,0xC7CB,0xD642,
0x2EB5,0x3F3C,0x0DA7,0x1C2E,0x6891,0x7918,0x4B83,0x5A0A,
0x937E,0x82F7,0xB06C,0xA1E5,0xD55A,0xC4D3,0xF648,0xE7C1,
0x1F36,0x0EBF,0x3C24,0x2DAD,0x5912,0x489B,0x7A00,0x6B89,
0x83FF,0x9276,0xA0ED,0xB164,0xC5DB,0xD452,0xE6C9,0xF740,
0x0FB7,0x1E3E,0x2CA5,0x3D2C,0x4993,0x581A,0x6A81,0x7B08,
0x7470,0x65F9,0x5762,0x46EB,0x3254,0x23DD,0x1146,0x00CF,
0xF838,0xE9B1,0xDB2A,0xCAA3,0xBE1C,0xAF95,0x9D0E,0x8C87,
0x64F1,0x7578,0x47E3,0x566A,0x22D5,0x335C,0x01C7,0x104E,
0xE8B9,0xF930,0xCBAB,0xDA22,0xAE9D,0xBF14,0x8D8F,0x9C06,
0x5572,0x44FB,0x7660,0x67E9,0x1356,0x02DF,0x3044,0x21CD,
0xD93A,0xC8B3,0xFA28,0xEBA1,0x9F1E,0x8E97,0xBC0C,0xAD85,
0x45F3,0x547A,0x66E1,0x7768,0x03D7,0x125E,0x20C5,0x314C,
0xC9BB,0xD832,0xEAA9,0xFB20,0x8F9F,0x9E16,0xAC8D,0xBD04,
0x3674,0x27FD,0x1566,0x04EF,0x7050,0x61D9,0x5342,0x42CB,
0xBA3C,0xABB5,0x992E,0x88A7,0xFC18,0xED91,0xDF0A,0xCE83,
0x26F5,0x377C,0x05E7,0x146E,0x60D1,0x7158,0x43C3,0x524A,
0xAABD,0xBB34,0x89AF,0x9826,0xEC99,0xFD10,0xCF8B,0xDE02,
0x1776,0x06FF,0x3464,0x25ED,0x5152,0x40DB,0x7240,0x63C9,
0x9B3E,0x8AB7,0xB82C,0xA9A5,0xDD1A,0xCC93,0xFE08,0xEF81,
0x07F7,0x167E,0x24E5,0x356C,0x41D3,0x505A,0x62C1,0x7348,
0x8BBF,0x9A36,0xA8AD,0xB924,0xCD9B,0xDC12,0xEE89,0xFF00
}; int CRCVal=0;
int i=0; for(i=0; i <data.length; i++){
CRCVal = CRCTABLE[(CRCVal ^= ((data[i]) & 0xFF)) & 0xFF] ^ (CRCVal>>8);
} return Integer.toHexString(CRCVal);
}