使用.NET Framework;有Convert.ToBase64String(byteArray)
的更快替代方案吗?
更新
为了给出更多进一步的背景信息,我正在为发件人不同的电子邮件编码文件附件,因此我将在循环中为此编码相当多的(假设为1000)> 1MB文件。
简化示例:
for(int i = 0; i < 1000; i++) {
var file = System.IO.File.ReadAllBytes("c:\\temp\\clientfile" + i + ".pdf");
System.IO.File.WriteAllText("c:\\emailsendtest\\test" + i + ".tmp", Convert.ToBase64String(file));
}
答案 0 :(得分:4)
以下是一些比较两种方法的数据(Convert ...和Cryptography ...)。我运行了200次测试,写出100万字节到一个新的1 MB文件。看起来Convert.ToBase64方法平均比加密方法快七倍左右。测试运行的直方图如下:
如果有人有兴趣验证我的结果 - 这是我的测试代码:
private static void Test()
{
Random myRand = new Random();
List<TimeSpan> convert64Times = new List<TimeSpan>();
List<TimeSpan> cryptoTimes = new List<TimeSpan>();
Stopwatch theTimer = new Stopwatch();
for (int i = 0; i < 200; i++)
{
byte[] randBytes = new byte[1000000];
myRand.NextBytes(randBytes);
string filePrefix = @"C:\Temp\file";
// test encode with convert to base 64
theTimer.Start();
EncodeWithConvertToBase64(randBytes,filePrefix+i+"convert.txt");
theTimer.Stop();
convert64Times.Add(theTimer.Elapsed);
theTimer.Reset();
// test encode with crypto
theTimer.Start();
EncodeWithCryptoClass(randBytes,filePrefix+i+"crypto.txt");
theTimer.Stop();
cryptoTimes.Add(theTimer.Elapsed);
theTimer.Reset();
}
}
private static void EncodeWithConvertToBase64(byte[] inputBytes, string targetFile)
{
string fileString = Convert.ToBase64String(inputBytes);
using (StreamWriter output = new StreamWriter(targetFile))
{
output.Write(fileString);
output.Close();
}
}
private static void EncodeWithCryptoClass(byte[] inputBytes, string targetFile)
{
FileStream outputFileStream =
new FileStream(targetFile, FileMode.Create, FileAccess.Write);
// Create a new ToBase64Transform object to convert to base 64.
ToBase64Transform base64Transform = new ToBase64Transform();
// Create a new byte array with the size of the output block size.
byte[] outputBytes = new byte[base64Transform.OutputBlockSize];
// Verify that multiple blocks can not be transformed.
if (!base64Transform.CanTransformMultipleBlocks)
{
// Initializie the offset size.
int inputOffset = 0;
// Iterate through inputBytes transforming by blockSize.
int inputBlockSize = base64Transform.InputBlockSize;
while (inputBytes.Length - inputOffset > inputBlockSize)
{
base64Transform.TransformBlock(
inputBytes,
inputOffset,
inputBytes.Length - inputOffset,
outputBytes,
0);
inputOffset += base64Transform.InputBlockSize;
outputFileStream.Write(
outputBytes,
0,
base64Transform.OutputBlockSize);
}
// Transform the final block of data.
outputBytes = base64Transform.TransformFinalBlock(
inputBytes,
inputOffset,
inputBytes.Length - inputOffset);
outputFileStream.Write(outputBytes, 0, outputBytes.Length);
}
// Determine if the current transform can be reused.
if (!base64Transform.CanReuseTransform)
{
// Free up any used resources.
base64Transform.Clear();
}
// Close file streams.
outputFileStream.Close();
}
答案 1 :(得分:1)
假设您的文件附件是作为流读入的,建议您使用System.Security.Cryptography中的ToBase64Transform类而不是Convert类。
可以在该页面上找到一个完整的示例,该示例从输入文件中读取并写回编码文件。
您还应该看看JMarsch的示例,找到here。