c#读写大文件（大于20g）

Question

c#读写大文件（大于20g），是二进制大文件的读写，谢谢各位

Answer 1

The problem with your solution is that you recreate the streams in each iteration. Try this version:

const int MAX_BUFFER = 33554432; //32MB
byte[] buffer = new byte[MAX_BUFFER];
int bytesRead;
StringBuilder currentLine = new StringBuilder();

using (FileStream fs = File.Open(filePath, FileMode.Open, FileAccess.Read))
using (BufferedStream bs = new BufferedStream(fs))
{
    string line;
    bool stop = false;
    var memoryStream = new MemoryStream(buffer);
    var stream = new StreamReader(memoryStream);
    while ((bytesRead = bs.Read(buffer, 0, MAX_BUFFER)) != 0)
    {
        memoryStream.Seek(0, SeekOrigin.Begin);

        while (!stream.EndOfStream)
        {
            line = ReadLineWithAccumulation(stream, currentLine);

            if (line != null)
            {
                //process line
            }
        }
    }
}

private string ReadLineWithAccumulation(StreamReader stream, StringBuilder currentLine)
{
    while (stream.Read(buffer, 0, 1) > 0)
    {
        if (charBuffer [0].Equals('\n'))
        {
            string result = currentLine.ToString();
            currentLine.Clear();

            if (result.Last() == '\r') //remove if newlines are single character
            {
                result = result.Substring(0, result.Length - 1);
            }

            return result;
        }
        else
        {
            currentLine.Append(charBuffer [0]);
        }
    }

    return null;  //line not complete yet
}

private char[] charBuffer = new char[1];

c# - Read a very large file by chunks and not line-by-line - Stack Overflow https://stackoverflow.com/questions/21136753/read-a-very-large-file-by-chunks-and-not-line-by-line