java 二进制数据与16进制字符串相互转化方法

 public static String bytesToHexString(byte[] src){
  StringBuilder stringBuilder = new StringBuilder();
  if (src == null || src.length <= 0) {
   return null;
  }
  for (int i = 0; i < src.length; i++) {
   int v = src[i] & 0xFF;
   String hv = Integer.toHexString(v);
 
   stringBuilder.append(i + ":");
 
   if (hv.length() < 2) {
    stringBuilder.append(0);
   }
   stringBuilder.append(hv + ";");
  }
  return stringBuilder.toString();
 }

public static byte[] hexStringToByte(String hex) {
  int len = (hex.length() / 2);
  byte[] result = new byte[len];
  char[] achar = hex.toCharArray();
  for (int i = 0; i < len; i++) {
   int pos = i * 2;
   result[i] = (byte) (toByte(achar[pos]) << 4 | toByte(achar[pos + 1]));
  }
  return result;
 }
 
 private static byte toByte(char c) {
  byte b = (byte) "0123456789abcdef".indexOf(c);
  return b;
 }