简单的HttpURLConnection POST文件multipart/form-data从android到google blobstore

我尝试了以下代码 -

private static void postToUrl(String url_to_upload_on,
        String file_name_with_ext, byte[] byteArray) {

    String attachmentName = "file";
    String attachmentFileName = file_name_with_ext;
    String crlf = "\r\n";
    String twoHyphens = "--";
    String boundary =  "*****";

    try{

    URL url = new URL(url_to_upload_on);
    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
    connection.setDoOutput(true);
    connection.setRequestMethod("POST");

    connection.setRequestProperty(
        "Content-Type", "multipart/form-data;boundary=" + boundary);
    DataOutputStream request = new DataOutputStream(
            connection.getOutputStream()); 
    request.writeBytes(twoHyphens + boundary + crlf);
    request.writeBytes("Content-Disposition: form-data; name=\"" +
        attachmentName + "\";filename=\"" + 
        attachmentFileName + "\"" + crlf);
    request.writeBytes(crlf);
    request.write(byteArray);
    request.writeBytes(crlf);
    request.writeBytes(twoHyphens + boundary + 
        twoHyphens + crlf);
    request.flush();
    request.close();

    }catch(Exception e){
        e.printStackTrace();
    }


}

这给了我没有直接的错误,但当我得到错误流使用 -

 Log.w(TAG, "connection.getErrorStream() = " +      connection.getErrorStream());

我明白了 -

12-14 18:25:54.911: W/uploadToBlobStore(30558): httpUrlConnection.getErrorStream() = com.android.okhttp.internal.http.HttpTransport$FixedLengthInputStream@426dd5a8

没有成功.

PS-我正在将文件上传到google blobstore

PS-我不能使用Apache http库或其多部分类,因为android称其折旧

编辑1

现在我使用以下代码,但它仅适用于低于2.3Mb的文件 -

private static void postToUrl3(String url_to_upload_on,
        String file_name_with_ext, byte[] byteArray, String mimeType) {

    CloseableHttpClient httpClient = null;

    try {

        httpClient = HttpClientBuilder.create().build();

        HttpPost postRequest = new HttpPost(url_to_upload_on);


        MultipartEntityBuilder reqEntity = MultipartEntityBuilder.create();
        reqEntity.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);            
        ByteArrayBody bab = new ByteArrayBody(byteArray, file_name_with_ext);           
        reqEntity.addPart("file", bab);         
        postRequest.setEntity(reqEntity.build());


        httpClient.execute(postRequest);// takes time

    } catch (Exception e) {
        Log.w("uploadToBlobStore", "postToUrl Exception e = " + e);
        e.printStackTrace();
    } finally {
        if (httpClient != null) {
            Log.w("uploadToBlobStore", "connection.closing ");
            try {
                httpClient.close();
            } catch (IOException e) {
                Log.w("uploadToBlobStore", "connection.closing errot e = "
                        + e);
                e.printStackTrace();
            }
        }
    }
}

如何使它适用于更大的文件？

PS-我发送它BLOBSTORE和我没有设置maxUploadSizeBytes并MaxUploadSizeBytesPerBlob以30MB.I我无法弄清楚这个问题与大小,因为谷歌BLOBSTORE文件说-

Google App Engine包含Blobstore服务,该服务允许应用程序提供仅受可通过单个HTTP连接上载或下载的数据量限制的数据对象.

那么http连接会出现问题吗？如果是这样,我该如何配置它.

我HttpURLConnection用来实现这一目标.

创建一个Multipart自定义类::

public class MultipartUtility {
    private final String boundary;
    private static final String LINE_FEED = "\r\n";
    private HttpURLConnection httpConn;
    private String charset;
    private OutputStream outputStream;
    private PrintWriter writer;

    /**
     * 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)
            throws IOException {
        this.charset = charset;

        // creates a unique boundary based on time stamp
        boundary = "===" + System.currentTimeMillis() + "===";
        URL url = new URL(requestURL);
        httpConn = (HttpURLConnection) url.openConnection();
        httpConn.setUseCaches(false);
        httpConn.setDoOutput(true);    // indicates POST method
        httpConn.setDoInput(true);
        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 
     * @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;
        while ((bytesRead = inputStream.read(buffer)) != -1) {
            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 List finish() throws IOException {
        List response = new ArrayList();
        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.add(line);
            }
            reader.close();
            httpConn.disconnect();
        } else {
            throw new IOException("Server returned non-OK status: " + status);
        }
        return response;
    }
}

使用它(异步方式)::

    MultipartUtility multipart = new MultipartUtility(requestURL, charset);

    // In your case you are not adding form data so ignore this
                /*This is to add parameter values */
                for (int i = 0; i < myFormDataArray.size(); i++) {
                    multipart.addFormField(myFormDataArray.get(i).getParamName(),
                            myFormDataArray.get(i).getParamValue());
                }


//add your file here.
                /*This is to add file content*/
                for (int i = 0; i < myFileArray.size(); i++) {
                    multipart.addFilePart(myFileArray.getParamName(),
                            new File(myFileArray.getFileName()));
                }

                List response = multipart.finish();
                Debug.e(TAG, "SERVER REPLIED:");
                for (String line : response) {
                    Debug.e(TAG, "Upload Files Response:::" + line);
// get your server response here.
                    responseString = line;
                }

使用okhttp并使用以下代码段(取自食谱)

根据服务器的期望调整标头值.

private static final String IMGUR_CLIENT_ID = "...";
private static final MediaType MEDIA_TYPE_PNG = MediaType.parse("image/png");

private final OkHttpClient client = new OkHttpClient();

public void run() throws Exception {
// Use the imgur image upload API as documented at https://api.imgur.com/endpoints/image
    RequestBody requestBody = new MultipartBuilder()
    .type(MultipartBuilder.FORM)
    .addPart(
        Headers.of("Content-Disposition", "form-data; name=\"title\""),
        RequestBody.create(null, "Square Logo"))
    .addPart(
        Headers.of("Content-Disposition", "form-data; name=\"image\""),
        RequestBody.create(MEDIA_TYPE_PNG, new File("website/static/logo-square.png")))
    .build();

Request request = new Request.Builder()
    .header("Authorization", "Client-ID " + IMGUR_CLIENT_ID)
    .url("https://api.imgur.com/3/image")
    .post(requestBody)
    .build();

Response response = client.newCall(request).execute();
if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

System.out.println(response.body().string());
}

作为替代方案,您可以使用Retrofit.

你可以像这样指定一个电话:

@Multipart
@POST("/user/photo")
Call updateUser(@Part("photo") RequestBody photo, @Part("description") RequestBody description);

然后像这样创建它:

Retrofit retrofit = new Retrofit.Builder()
    .baseUrl("https://api.github.com")
    .build();
GitHubService service = retrofit.create(GitHubService.class);

最后像这样执行:

service.updateUser(Photo, description).enqueue() - > 异步

service.updateUser(Photo, description).execute()- > 同步

请参阅此处的文档