如何将字节数组转换为十六进制字符串，反之亦然？
当前回答
为了方便以后复制和粘贴，将几个答案合并到一个类中：
/// <summary>
/// Extension methods to quickly convert byte array to string and back.
/// </summary>
public static class HexConverter
{
/// <summary>
/// Map values to hex digits
/// </summary>
private static readonly char[] HexDigits =
{
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
};
/// <summary>
/// Map 56 characters between ['0', 'F'] to their hex equivalents, and set invalid characters
/// such that they will overflow byte to fail conversion.
/// </summary>
private static readonly ushort[] HexValues =
{
0x0000, 0x0001, 0x0002, 0x0003, 0x0004, 0x0005, 0x0006, 0x0007, 0x0008, 0x0009, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100,
0x000A, 0x000B, 0x000C, 0x000D, 0x000E, 0x000F, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100,
0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x000A, 0x000B,
0x000C, 0x000D, 0x000E, 0x000F
};
/// <summary>
/// Empty byte array
/// </summary>
private static readonly byte[] Empty = new byte[0];
/// <summary>
/// Convert a byte array to a hexadecimal string.
/// </summary>
/// <param name="bytes">
/// The input byte array.
/// </param>
/// <returns>
/// A string of hexadecimal digits.
/// </returns>
public static string ToHexString(this byte[] bytes)
{
var c = new char[bytes.Length * 2];
for (int i = 0, j = 0; i < bytes.Length; i++)
{
c[j++] = HexDigits[bytes[i] >> 4];
c[j++] = HexDigits[bytes[i] & 0x0F];
}
return new string(c);
}
/// <summary>
/// Parse a string of hexadecimal digits into a byte array.
/// </summary>
/// <param name="hexadecimalString">
/// The hexadecimal string.
/// </param>
/// <returns>
/// The parsed <see cref="byte[]"/> array.
/// </returns>
/// <exception cref="ArgumentException">
/// The input string either contained invalid characters, or was of an odd length.
/// </exception>
public static byte[] ToByteArray(string hexadecimalString)
{
if (!TryParse(hexadecimalString, out var value))
{
throw new ArgumentException("Invalid hexadecimal string", nameof(hexadecimalString));
}
return value;
}
/// <summary>
/// Parse a hexadecimal string to bytes
/// </summary>
/// <param name="hexadecimalString">
/// The hexadecimal string, which must be an even number of characters.
/// </param>
/// <param name="value">
/// The parsed value if successful.
/// </param>
/// <returns>
/// True if successful.
/// </returns>
public static bool TryParse(string hexadecimalString, out byte[] value)
{
if (hexadecimalString.Length == 0)
{
value = Empty;
return true;
}
if (hexadecimalString.Length % 2 != 0)
{
value = Empty;
return false;
}
try
{
value = new byte[hexadecimalString.Length / 2];
for (int i = 0, j = 0; j < hexadecimalString.Length; i++)
{
value[i] = (byte)((HexValues[hexadecimalString[j++] - '0'] << 4)
| HexValues[hexadecimalString[j++] - '0']);
}
return true;
}
catch (OverflowException)
{
value = Empty;
return false;
}
}
}
其他回答
可以使用从.NET 5开始的Convert.ToHexString。还有一个用于反向操作的方法：Convert.FromHexString。
对于较旧版本的.NET，您可以使用：
public static string ByteArrayToString(byte[] ba)
{
StringBuilder hex = new StringBuilder(ba.Length * 2);
foreach (byte b in ba)
hex.AppendFormat("{0:x2}", b);
return hex.ToString();
}
or:
public static string ByteArrayToString(byte[] ba)
{
return BitConverter.ToString(ba).Replace("-","");
}
举个例子，这里有更多的方法。
反向转换如下：
public static byte[] StringToByteArray(String hex)
{
int NumberChars = hex.Length;
byte[] bytes = new byte[NumberChars / 2];
for (int i = 0; i < NumberChars; i += 2)
bytes[i / 2] = Convert.ToByte(hex.Substring(i, 2), 16);
return bytes;
}
使用Substring是与Convert.ToByte结合使用的最佳选项。有关详细信息，请参阅此答案。如果需要更好的性能，必须避免Convert.ToByte，然后才能删除SubString。
为了方便以后复制和粘贴，将几个答案合并到一个类中：
/// <summary>
/// Extension methods to quickly convert byte array to string and back.
/// </summary>
public static class HexConverter
{
/// <summary>
/// Map values to hex digits
/// </summary>
private static readonly char[] HexDigits =
{
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
};
/// <summary>
/// Map 56 characters between ['0', 'F'] to their hex equivalents, and set invalid characters
/// such that they will overflow byte to fail conversion.
/// </summary>
private static readonly ushort[] HexValues =
{
0x0000, 0x0001, 0x0002, 0x0003, 0x0004, 0x0005, 0x0006, 0x0007, 0x0008, 0x0009, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100,
0x000A, 0x000B, 0x000C, 0x000D, 0x000E, 0x000F, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100,
0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x0100, 0x000A, 0x000B,
0x000C, 0x000D, 0x000E, 0x000F
};
/// <summary>
/// Empty byte array
/// </summary>
private static readonly byte[] Empty = new byte[0];
/// <summary>
/// Convert a byte array to a hexadecimal string.
/// </summary>
/// <param name="bytes">
/// The input byte array.
/// </param>
/// <returns>
/// A string of hexadecimal digits.
/// </returns>
public static string ToHexString(this byte[] bytes)
{
var c = new char[bytes.Length * 2];
for (int i = 0, j = 0; i < bytes.Length; i++)
{
c[j++] = HexDigits[bytes[i] >> 4];
c[j++] = HexDigits[bytes[i] & 0x0F];
}
return new string(c);
}
/// <summary>
/// Parse a string of hexadecimal digits into a byte array.
/// </summary>
/// <param name="hexadecimalString">
/// The hexadecimal string.
/// </param>
/// <returns>
/// The parsed <see cref="byte[]"/> array.
/// </returns>
/// <exception cref="ArgumentException">
/// The input string either contained invalid characters, or was of an odd length.
/// </exception>
public static byte[] ToByteArray(string hexadecimalString)
{
if (!TryParse(hexadecimalString, out var value))
{
throw new ArgumentException("Invalid hexadecimal string", nameof(hexadecimalString));
}
return value;
}
/// <summary>
/// Parse a hexadecimal string to bytes
/// </summary>
/// <param name="hexadecimalString">
/// The hexadecimal string, which must be an even number of characters.
/// </param>
/// <param name="value">
/// The parsed value if successful.
/// </param>
/// <returns>
/// True if successful.
/// </returns>
public static bool TryParse(string hexadecimalString, out byte[] value)
{
if (hexadecimalString.Length == 0)
{
value = Empty;
return true;
}
if (hexadecimalString.Length % 2 != 0)
{
value = Empty;
return false;
}
try
{
value = new byte[hexadecimalString.Length / 2];
for (int i = 0, j = 0; j < hexadecimalString.Length; i++)
{
value[i] = (byte)((HexValues[hexadecimalString[j++] - '0'] << 4)
| HexValues[hexadecimalString[j++] - '0']);
}
return true;
}
catch (OverflowException)
{
value = Empty;
return false;
}
}
}
我怀疑这样的速度会使大多数其他测试失败。。。
Public Function BufToHex(ByVal buf() As Byte) As String
Dim sB As New System.Text.StringBuilder
For i As Integer = 0 To buf.Length - 1
sB.Append(buf(i).ToString("x2"))
Next i
Return sB.ToString
End Function
另一种方法是使用stackaloc来降低GC内存压力：
static string ByteToHexBitFiddle(byte[] bytes)
{
var c = stackalloc char[bytes.Length * 2 + 1];
int b;
for (int i = 0; i < bytes.Length; ++i)
{
b = bytes[i] >> 4;
c[i * 2] = (char)(55 + b + (((b - 10) >> 31) & -7));
b = bytes[i] & 0xF;
c[i * 2 + 1] = (char)(55 + b + (((b - 10) >> 31) & -7));
}
c[bytes.Length * 2 ] = '\0';
return new string(c);
}
此版本的ByteArrayToHexViaByteManipulation可能更快。
从我的报告中：
ByteArrayToHexViaByteManipulation3:1.68次平均滴答声（超过1000次），17,5XByteArrayToHexViaByteManipulation2:1,73平均滴答（超过1000次），16,9XByteArrayToHexViaByteManipulation:2,90平均刻度（超过1000次），10,1XByteArrayToHexViaLookupAndShift:3.22平均刻度（超过1000次），9,1X...静态专用只读字符[]hexAlphabet=新字符[]{'0'，'1'，'2'，'3'，'4'，'5'，'6'，'7'，'8'，'9'，'A'，'B'，'C'，'D'，'E'，'F'}；静态字符串ByteArrayToHexViaByteManipulation3（byte[]字节）{char[]c=新字符[bytes.Length*2]；字节b；for（int i=0；i<bytes.Length；i++）{b=（（字节）（字节[i]>>4））；c[i*2]=十六进制字母[b]；b=（（字节）（字节[i]&0xF））；c[i*2+1]=十六进制字母[b]；}返回新字符串（c）；}
我认为这是一个优化：
static private readonly char[] hexAlphabet = new char[]
{'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
static string ByteArrayToHexViaByteManipulation4(byte[] bytes)
{
char[] c = new char[bytes.Length * 2];
for (int i = 0, ptr = 0; i < bytes.Length; i++, ptr += 2)
{
byte b = bytes[i];
c[ptr] = hexAlphabet[b >> 4];
c[ptr + 1] = hexAlphabet[b & 0xF];
}
return new string(c);
}
