读取大文件 [英] Read large files

问题描述

我尝试通过两种方式读取2+ gb文件，第一种:

I tried to read a 2+ gb file in two ways, the first:

var file = File.ReadAllBytes(filepath);

返回一个异常，文件大小超过2GB.

returns an exception, file over 2gb.

第二种方式:

var file = ReadAllBytes(filepath);

public byte[] ReadAllBytes(string fileName)
{
    byte[] buffer = null;

    using (FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read))
    {
        buffer = new byte[fs.Length];
        fs.Read(buffer, 0, (int)fs.Length);
    }

    return buffer;
}

异常:数组尺寸超出了支持的范围." 我的目标是将文件发送到http请求的正文中(使用WebClient类).

Exception: "Array dimensions exceeded supported range." My goal is to send the file in the body of http request (using WebClient class).

有任何有关读取大文件的示例吗?

Any example of how to read large files?

谢谢

推荐答案

您可以尝试以下操作:

public void ProcessLargeFile(string fileName)
{
    int bufferSize = 100 * 1024 * 1024; // 100MB
    byte[] buffer = new byte[bufferSize];
    int bytesRead = 0;

    using (FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read))
    {
        while ((bytesRead = fs.Read(buffer, 0, bufferSize)) > 0)
        {
            if (bytesRead < bufferSize)
            {
                // please note array contains only 'bytesRead' bytes from 'bufferSize'
            }

            // here 'buffer' you get current portion on file 
            // process this
        }
    }
}

这将允许您按100MB的部分处理文件，您可以将此值更改为必需的值.

That will allow you to process file by 100MB portions, you can change this value to required one.

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