在Android中上传多部分图片时出现服务器错误415

Question

通过服务器上传图像文件时，我收到来自服务器的不受支持的文件格式错误。

我已经跟踪了一个网址，并使用了我的舒适的代码。

public class MultipartUtility {
    private final String boundary;
    private static final String LINE_FEED = "\r\n";
    private static final int CONNECTION_TIMEOUT = 5000; // 5 Seconds
    private HttpURLConnection httpConn;
    private String charset;
    private OutputStream outputStream;
    private PrintWriter writer;
    String authToken;

    /**
     * This constructor initializes a new HTTP POST request with content type
     * is set to multipart/form-data
     * @param requestURL
     * @param charset
     * @throws IOException
     */
    public MultipartUtility(String requestURL, String charset,  String authtoken)
            throws IOException {
        this.charset = charset;
        this.authToken = authtoken;

        // creates a unique boundary based on time stamp
        boundary = "===" + System.currentTimeMillis() + "===";

        URL url = new URL(requestURL);
        httpConn = (HttpURLConnection) url.openConnection();
        httpConn.setUseCaches(false);
        httpConn.setConnectTimeout(CONNECTION_TIMEOUT);
        httpConn.setDoOutput(true); // indicates POST method
        httpConn.setDoInput(true);
        httpConn.setRequestProperty("X-Auth-Token", authtoken);
        httpConn.setRequestProperty("Content-Type",
                "multipart/form-data; boundary=" + boundary);
        outputStream = httpConn.getOutputStream();
        writer = new PrintWriter(new OutputStreamWriter(outputStream, charset),
                true);
    }

    /**
     * Adds a form field to the request
     * @param name field name
     * @param value field value
     */
    public void addFormField(String name, String value) {
        writer.append("--" + boundary).append(LINE_FEED);
        writer.append("Content-Disposition: form-data; name=\"" + name + "\"")
                .append(LINE_FEED);
        writer.append("Content-Type: text/plain; charset=" + charset).append(
                LINE_FEED);
        writer.append(LINE_FEED);
        writer.append(value).append(LINE_FEED);
        writer.flush();
    }

    /**
     * Adds a upload file section to the request
     * @param fieldName name attribute in <input type="file" name="..." />
     * @param uploadFile a File to be uploaded
     * @throws IOException
     */
    public void addFilePart(String fieldName, File uploadFile)
            throws IOException {
        String fileName = uploadFile.getName();
        writer.append("--" + boundary).append(LINE_FEED);
        writer.append(
                "Content-Disposition: form-data; name=\"" + fieldName
                        + "\"; filename=\"" + fileName + "\"")
                .append(LINE_FEED);
        writer.append(
                "Content-Type: "
                        + URLConnection.guessContentTypeFromName(fileName))
                .append(LINE_FEED);
        writer.append("Content-Transfer-Encoding: binary").append(LINE_FEED);
        writer.append(LINE_FEED);
        writer.flush();

        FileInputStream inputStream = new FileInputStream(uploadFile);
        byte[] buffer = new byte[4096];
        int bytesRead = -1;
        long total = 0;
        while ((bytesRead = inputStream.read(buffer)) != -1) {
            /*if (listener != null) {
                total += bytesRead;
                //listener.onProgress((int) ((total * 100) / uploadFile.length()));
            }*/
            outputStream.write(buffer, 0, bytesRead);
        }
        outputStream.flush();
        inputStream.close();

        writer.append(LINE_FEED);
        writer.flush();
    }

    /**
     * Adds a header field to the request.
     * @param name - name of the header field
     * @param value - value of the header field
     */
    public void addHeaderField(String name, String value) {
        writer.append(name + ": " + value).append(LINE_FEED);
        writer.flush();
    }

    /**
     * Completes the request and receives response from the server.
     * @return a list of Strings as response in case the server returned
     * status OK, otherwise an exception is thrown.
     * @throws IOException
     */
    public String finish() throws IOException {
        StringBuilder response = null;

        writer.append(LINE_FEED).flush();
        writer.append("--" + boundary + "--").append(LINE_FEED);
        writer.close();

        // checks server's status code first
        int status = httpConn.getResponseCode();
        if (status == HttpURLConnection.HTTP_OK) {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    httpConn.getInputStream()));
            String line = null;
            while ((line = reader.readLine()) != null) {
                response.append(line);
            }
            reader.close();
            httpConn.disconnect();
        } else {
            throw new IOException("Server returned non-OK status: " + status + " " + httpConn.getErrorStream());
        }

        return response.toString();
    }
}

并从AsyncTask使用此类。

MultipartUtility multipart = new MultipartUtility(url, charset, authToken);
            multipart.addFormField("guestId", params[1]);
            multipart.addFilePart("file", new File(params[0]));
            String response = multipart.finish(); // response from server.

我太该死了，无法指出自己的小错误。

请你帮我一下。

谢谢。

Answer 1

我认为“ URLConnection.guessContentTypeFromName（fileName）”未返回正确的内容类型。 由于您提到要将图像作为文件发送，因此请尝试将addimagePart（）方法中的“ image / *”或“ image / jpeg”（如果您知道图像类型）硬编码为“ Content-Type”标头字段的值。 希望能有所帮助。