编码问题？

发布于 2024-10-25 08:52:31 字数 807 浏览 0 评论 0原文

我想从网络上获取一张图片，并将其转换为字节数组。但阅读回复时发现有问题。我怀疑这是由编码模式引起的。

        WebRequest request = WebRequest.Create("http://www.waterfootprint.org/images/gallery/original/apple.jpg");
        request.Method = "GET";
        request.Timeout = 10000;
        using (WebResponse response = request.GetResponse())
        {
            Stream stream = response.GetResponseStream();
            Encoding encoding = Encoding.UTF8;
            StreamReader streamReader = new StreamReader(stream, encoding);

            string responseBody = streamReader.ReadToEnd(); //always invalid characters here
            streamReader.Close();
            stream.Dispose();
            byte[] buffer = Convert.FromBase64String(responseBody); 
        }

我尝试过其他编码方式，比如UTF7、Unicode等，但都是徒劳。有人能告诉我为什么吗？谢谢

原文

I want to get a picture from web, and turn that into a byte array. But there is something wrong reading the response. I suspect it caused by encoding modes.

        WebRequest request = WebRequest.Create("http://www.waterfootprint.org/images/gallery/original/apple.jpg");
        request.Method = "GET";
        request.Timeout = 10000;
        using (WebResponse response = request.GetResponse())
        {
            Stream stream = response.GetResponseStream();
            Encoding encoding = Encoding.UTF8;
            StreamReader streamReader = new StreamReader(stream, encoding);

            string responseBody = streamReader.ReadToEnd(); //always invalid characters here
            streamReader.Close();
            stream.Dispose();
            byte[] buffer = Convert.FromBase64String(responseBody); 
        }

I have tried other encoding ways, such as UTF7, Unicode, etc, but all in vain. Could someone tell me why? Thanks

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GRAY°灰色天空 2024-11-01 08:52:31

    StreamReader streamReader = new StreamReader(stream, encoding);

StreamReader 是一个 < em>TextReader 以特定编码从字节流中读取字符。

StreamReader 是为字符设计的
以特定编码输入，
而 Stream 类的设计
用于字节输入和输出。使用
StreamReader 用于读取行
来自标准文本文件的信息。

在您的情况下，您收到原始字节 - 您需要直接使用 Stream、使用 BinaryReader 或更高级别的抽象。

        byte[] buffer = Convert.FromBase64String(responseBody);

您获得的流不是 base64 编码的 - 它是纯图像字节流，因此只需直接分配字节，最简单的方法是使用 WebClient:

using(WebClient wc = new WebClient())
byte[] buffer = wc.DownloadData("http://www.waterfootprint.org/images/gallery/original/apple.jpg");

    StreamReader streamReader = new StreamReader(stream, encoding);

StreamReader is a TextReader that reads characters from a byte stream in a particular encoding.

StreamReader is designed for character
input in a particular encoding,
whereas the Stream class is designed
for byte input and output. Use
StreamReader for reading lines of
information from a standard text file.

In your case you receive raw bytes - You either need to work with the Stream directly, use a BinaryReader or a higher level abstraction.

        byte[] buffer = Convert.FromBase64String(responseBody);

The stream you are getting is not base64 encoded - it's a pure image byte stream, so just assign the bytes directly, easiest would be with a WebClient:

using(WebClient wc = new WebClient())
byte[] buffer = wc.DownloadData("http://www.waterfootprint.org/images/gallery/original/apple.jpg");

Base 64 encoding is usually used when you must transmit binary data as ASCII text (i.e. as part of an XML CData element or SOAP in general) - but not if you want to transmit a binary file (i.e. an image) over HTTP.

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卖梦商人 2024-11-01 08:52:31

它以二进制形式返回，而不是 base-64 编码。例如，如果我更改代码以直接从响应流创建图像，我会看到它出现在 PictureBox 控件中。

    private void button1_Click(object sender, EventArgs e)
    {
        WebRequest request = WebRequest.Create("http://www.waterfootprint.org/images/gallery/original/apple.jpg");
        request.Method = "GET";
        request.Timeout = 10000;
        using (WebResponse response = request.GetResponse())
        {
            Stream stream = response.GetResponseStream();
            Bitmap b = (Bitmap)Bitmap.FromStream(response.GetResponseStream());
            pictureBox1.Image = b;
        }
    }

It comes back as binary, not base-64 encoded. For example, if I change your code to create an image directly from the response stream, I see it appear in a PictureBox control.

    private void button1_Click(object sender, EventArgs e)
    {
        WebRequest request = WebRequest.Create("http://www.waterfootprint.org/images/gallery/original/apple.jpg");
        request.Method = "GET";
        request.Timeout = 10000;
        using (WebResponse response = request.GetResponse())
        {
            Stream stream = response.GetResponseStream();
            Bitmap b = (Bitmap)Bitmap.FromStream(response.GetResponseStream());
            pictureBox1.Image = b;
        }
    }

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