Java hexadecimal characters and byte array conversions __java

The recent project needs to convert a byte array to a hexadecimal number, which has been studied for a long time and shared

converting between byte arrays and hexadecimal strings

/** * Convert byte[] to hex * string. Here we can convert byte to int and then use integer.tohexstring (int) to convert into a 16-string. * @param src * @return/public String bytestohexstring (byte[] src) {StringBuilder StringBuilder = new Stringbuil
		Der ("");
		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);
			if (Hv.length () < 2) {stringbuilder.append (0);
		} stringbuilder.append (HV);
	return stringbuilder.tostring ();  /** * Convert hex string to byte[] * * @param hexstring * @return/public byte[] Hexstringtobytes (string
		hexstring) {if (hexstring = = NULL | | | hexstring.equals ("")) {return null;	}//hexstring = Hexstring.touppercase ();
		If it is uppercase int length = Hexstring.length ()/2;
		char[] Hexchars = Hexstring.tochararray ();
		Byte[] D = new Byte[length];
			for (int i = 0; i < length; i++) {int pos = i * 2; D[i] = (byte) (ChartobyTe (Hexchars[pos]) << 4 |
		Chartobyte (Hexchars[pos + 1]));
	return D; Private byte Chartobyte (char c) {return (byte) ' 0123456789abcdef '. IndexOf (c);//Return (byte) "0123456789ABCDEF".
	IndexOf (c); }

the conversion between a string and its corresponding UTF-8 encoding

/** * Convert UTF-8 code string to string, capable of handling kanji * @param s * @return/public static string Convertutf8tost
		Ring (String s) {if (s = = NULL | | s.equals ("")) {return null;

			try {s = s.touppercase ();
			int total = S.length ()/2;

			int pos = 0;
			byte[] buffer = new Byte[total];

				for (int i = 0; i < total; i++) {int start = i * 2;
				Buffer[i] = (byte) integer.parseint (s.substring (Start, start + 2), 16);
			pos++;

		return new String (buffer, 0, POS, "UTF-8");
		catch (Unsupportedencodingexception e) {e.printstacktrace ();
	return s; /** * Convert String to UTF code string, capable of handling kanji * * @param S * Original String * @return/public static St
		Ring ConvertStringToUTF8 (String s) {if (s = = NULL | | s.equals ("")) {return null;
		StringBuffer sb = new StringBuffer ();
			try {char C;
				for (int i = 0; i < s.length (); i++) {c = S.charat (i); Byte[] B = character.tostring (c). GetBytes ("UTF-8 ");  if (c >= 0 && C <= 255) {//123...9-A-Z for (int j = 0; J < B.length; J +) {int k =
						B[J];
						if (k < 0) k = 256;	Sb.append ("0000" +integer.tohexstring (k). toUpperCase ());
					Consider the case of ASICII code characters//Sb.append (Integer.tohexstring (k). toUpperCase ());
						} else {for (int j = 0; J < B.length; J + +) {int k = b[j];
						if (k < 0) k = 256;
					Sb.append (Integer.tohexstring (k). toUpperCase ());

		catch (Exception e) {e.printstacktrace ()}}};
	return sb.tostring (); }

converts a byte array to long

	 * * Byte[]->long/public
	final static long Getlong (byte[] buf, boolean ASC) {
		if (buf = null) {
  
   throw New IllegalArgumentException ("byte array is null!");
		}
		if (Buf.length > 8) {
			throw new IllegalArgumentException ("byte array size > 8!");
		}
		Long r = 0;
		if (ASC) for
			(int i = buf.length-1 i >= 0; i--) {
				R <<= 8;
				R |= (Buf[i] & 0x000000ff);
			}
		else for
			(int i = 0; i < buf.length i++) {
				R <<= 8;
				R |= (Buf[i] & 0x000000ff);
			}
		return r;
	}