java¶þ½øÖÆ,×Ö½ÚÊý×é,×Ö·û,Ê®Áù½øÖÆ,BCD±àÂëת»»

// ÕûÊýµ½×Ö½ÚÊý×éת»»
 public static byte[] int2bytes(int n) {
  byte[] ab = new byte[4];
  ab[0] = (byte) (0xff & n);
  ab[1] = (byte) ((0xff00 & n) >> 8);
  ab[2] = (byte) ((0xff0000 & n) >> 16);
  ab[3] = (byte) ((0xff000000 & n) >> 24);
  return ab;
 }
 // ×Ö½ÚÊý×éµ½ÕûÊýµÄת»»
 public static int bytes2int(byte b[]) {
  int s = 0;
  s = ((((b[0] & 0xff) << 8 | (b[1] & 0xff)) << 8) | (b[2] & 0xff)) << 8
    | (b[3] & 0xff);
  return s;
 }
 // ×Ö½Úת»»µ½×Ö·û
 public static char byte2char(byte b) {
  return (char) b;
 }
 private final static byte[] hex = "0123456789ABCDEF".getBytes();
 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;
 }
 // ´Ó×Ö½ÚÊý×鵽ʮÁù½øÖÆ×Ö·û´®×ª»»
 public static String Bytes2HexString(byte[] b) {
  byte[] buff = new byte[2 * b.length];
  for (int i = 0; i < b.length; i++) {
   buff[2 * i] = hex[(b[i] >> 4) & 0x0f];
   buff[2 * i + 1] = hex[b[i] & 0x0f];
  }
  return new String(buff);
 }
 // ´ÓÊ®Áù½øÖÆ×Ö·û´®µ½×Ö½ÚÊý×éת»»
 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;
 } 
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