code: public static String byteArrayToHexString(byte[] b) {
  		StringBuffer sb = new StringBuffer();
  		for (int i = 0; i < b.length; i++) {
  			sb.append(byteToHexString(b[i]));
  		}
  		return new String(sb);
  	}
docs: 转换字节数组为十六进制字符串
  
  @param b
  字节数组
  @return 十六进制字符串