字符转换为16进制字符串以及转换回来的方法

	//16进制字符串转化为字节
	public static byte[] HexString2Bytes(String hexstr) {
		byte[] b = new byte[hexstr.length() / 2];
		int j = 0;
		for (int i = b.length-1; i >=0; i--) {
			char c0 = hexstr.charAt(j++);
			char c1 = hexstr.charAt(j++);
			b[i] = (byte) ((parse(c0) << 4) | parse(c1));
		}
		return b;
	}
	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;
	}

	//转换为16进制字符串
        public static String hexString(String str) {
		String ret = "";
		byte[] b;
		try {
			b = str.getBytes("GB2312");
			for (int i = b.length - 1; i >= 0; i--) {
				String hex = Integer.toHexString(b[i] & 0xFF);
				if (hex.length() == 1) {
					hex = '0' + hex;
				}
				ret += hex.toUpperCase();
			}
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		}
		return ret;
	}
	
	public static void main(String[] args) throws Exception {
		String str = hexString("好啊tianta了");
		System.out.println(str);
		byte[] b = HexString2Bytes(str);
		String s=new String(b,"GB2312");
		System.out.println(s);
	}