Java/PNG上传到.php

问题描述

这是我使用记事本编辑时本地.png文件的内容:

This is what the local .png file has when I edit it w/ notepad:

http://i.stack.imgur.com/TjNGl.png

这是我使用记事本编辑后上传的.png文件的内容:

This is what the uploaded .png file has when I edit it w/ notepad:

http://i.stack.imgur.com/2tXgN.png

为什么将'NUL'替换为'\ 0'?这会使文件损坏且无法使用.

Why is 'NUL' being replaced with '\0'? This makes the file corrupt and unusable.

我使用此Java代码上传本地.png:

I use this java code to upload the local .png:

public static byte[] imageToByte(File file) throws FileNotFoundException {
    FileInputStream fis = new FileInputStream(file);
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    byte[] buf = new byte[1024];
    try {
        for (int readNum; (readNum = fis.read(buf)) != -1;) {
            bos.write(buf, 0, readNum);
        }
    } catch (IOException ex) {
    }
    byte[] bytes = bos.toByteArray();
    return bytes;
}

public static void sendPostData(String url, HashMap<String, String> data)
        throws Exception {
    URL siteUrl = new URL(url);
    HttpURLConnection conn = (HttpURLConnection) siteUrl.openConnection();
    conn.setRequestMethod("POST");
    conn.setDoOutput(true);
    conn.setDoInput(true);

    DataOutputStream out = new DataOutputStream(conn.getOutputStream());

    Set keys = data.keySet();
    Iterator keyIter = keys.iterator();
    String content = "";
    for (int i = 0; keyIter.hasNext(); i++) {
        Object key = keyIter.next();
        if (i != 0) {
            content += "&";
        }
        content += key + "=" + URLEncoder.encode(data.get(key), "UTF-8");
    }
    System.out.println(content);
    out.writeBytes(content);
    out.flush();
    out.close();
    BufferedReader in = new BufferedReader(new InputStreamReader(
            conn.getInputStream()));
    String line = "";
    while ((line = in.readLine()) != null) {
        System.out.println(line);
    }
    in.close();
}

推荐答案

我只是在这里猜测

但是我认为URLEncoder的工作方式..它无法解码正确的字符字节.看一下这个 http://www.w3schools.com/tags/ref_urlencode.asp

But I think thats how URLEncoder works.. it doesn't decode the proper character bytes.Check this outhttp://www.w3schools.com/tags/ref_urlencode.asp

NUL null character %00

如果您有权访问站点php ..我建议将png数据的编码base64表示形式发布到PHP ..然后在php端解码base64 ..那么它将是100％准确的.由于URLEncoding接受所有base64字符.

If you have access to your site php.. I recommend posting a encoded base64 representation of the png data.. to PHP.. then decoding the base64 on php side.. it will be 100% accurate then. As all of base64 characters are accepted in URLEncoding.

或者，如果您超级懒惰并且仍然想使用UrlEncoder，则可以将每个NUL替换为字节0，这是毫无理由的增加了很多额外的处理.

Or if you are super lazy and still want to use UrlEncoder you can replace every NUL back with byte 0, which will yeah add a lot of extra processing for no reason.

但是您仍然可以始终使用multipart/form-data上载数据，因为这需要做更多的工作.

But then again you can always upload data using multipart/form-data as that requires alot more work..

我建议您快速修复一下，现在尝试使用base64编码技巧.

I'd recommand a quick fix for now try the base64 encoding trick.

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