如何在Android中使用Volley分段上传图像，并且如果网络出现暂停/故障，如何从停止点重新开始上传？
我尝试了使用分段上传图片的代码。它未经测试，所以我不知道它是否有效。我不知道第二部分是否可以实现。如果是，那怎么办？
MultipartRequest.java-
public class MultipartRequest extends Request<NetworkResponse> {
private final String twoHyphens = "--";
private final String lineEnd = "\r\n";
private final String boundary = "apiclient-" + System.currentTimeMillis();
private Response.Listener<NetworkResponse> mListener;
private Response.ErrorListener mErrorListener;
private Map<String, String> mHeaders;
/**
* Default constructor with predefined header and post method.
*
* @param url request destination
* @param headers predefined custom header
* @param listener on success achieved 200 code from request
* @param errorListener on error http or library timeout
*/
public MultipartRequest(String url, Map<String, String> headers,
Response.Listener<NetworkResponse> listener,
Response.ErrorListener errorListener) {
super(Method.POST, url, errorListener);
this.mListener = listener;
this.mErrorListener = errorListener;
this.mHeaders = headers;
}
/**
* Constructor with option method and default header configuration.
*
* @param method method for now accept POST and GET only
* @param url request destination
* @param listener on success event handler
* @param errorListener on error event handler
*/
public MultipartRequest(int method, String url,
Response.Listener<NetworkResponse> listener,
Response.ErrorListener errorListener) {
super(method, url, errorListener);
this.mListener = listener;
this.mErrorListener = errorListener;
}
@Override
public Map<String, String> getHeaders() throws AuthFailureError {
return (mHeaders != null) ? mHeaders : super.getHeaders();
}
@Override
public String getBodyContentType() {
return "multipart/form-data;boundary=" + boundary;
}
@Override
public byte[] getBody() throws AuthFailureError {
ByteArrayOutputStream bos = new ByteArrayOutputStream();
DataOutputStream dos = new DataOutputStream(bos);
try {
// populate text payload
Map<String, String> params = getParams();
if (params != null && params.size() > 0) {
textParse(dos, params, getParamsEncoding());
}
// populate data byte payload
Map<String, DataPart> data = getByteData();
if (data != null && data.size() > 0) {
dataParse(dos, data);
}
// close multipart form data after text and file data
dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);
return bos.toByteArray();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
/**
* Custom method handle data payload.
*
* @return Map data part label with data byte
* @throws AuthFailureError
*/
protected Map<String, DataPart> getByteData() throws AuthFailureError {
return null;
}
@Override
protected Response<NetworkResponse> parseNetworkResponse(NetworkResponse response) {
try {
return Response.success(
response,
HttpHeaderParser.parseCacheHeaders(response));
} catch (Exception e) {
return Response.error(new ParseError(e));
}
}
@Override
protected void deliverResponse(NetworkResponse response) {
mListener.onResponse(response);
}
@Override
public void deliverError(VolleyError error) {
mErrorListener.onErrorResponse(error);
}
/**
* Parse string map into data output stream by key and value.
*
* @param dataOutputStream data output stream handle string parsing
* @param params string inputs collection
* @param encoding encode the inputs, default UTF-8
* @throws IOException
*/
private void textParse(DataOutputStream dataOutputStream, Map<String, String> params, String encoding) throws IOException {
try {
for (Map.Entry<String, String> entry : params.entrySet()) {
buildTextPart(dataOutputStream, entry.getKey(), entry.getValue());
}
} catch (UnsupportedEncodingException uee) {
throw new RuntimeException("Encoding not supported: " + encoding, uee);
}
}
/**
* Parse data into data output stream.
*
* @param dataOutputStream data output stream handle file attachment
* @param data loop through data
* @throws IOException
*/
private void dataParse(DataOutputStream dataOutputStream, Map<String, DataPart> data) throws IOException {
for (Map.Entry<String, DataPart> entry : data.entrySet()) {
buildDataPart(dataOutputStream, entry.getValue(), entry.getKey());
}
}
/**
* Write string data into header and data output stream.
*
* @param dataOutputStream data output stream handle string parsing
* @param parameterName name of input
* @param parameterValue value of input
* @throws IOException
*/
private void buildTextPart(DataOutputStream dataOutputStream, String parameterName, String parameterValue) throws IOException {
dataOutputStream.writeBytes(twoHyphens + boundary + lineEnd);
dataOutputStream.writeBytes("Content-Disposition: form-data; name=\"" + parameterName + "\"" + lineEnd);
//dataOutputStream.writeBytes("Content-Type: text/plain; charset=UTF-8" + lineEnd);
dataOutputStream.writeBytes(lineEnd);
dataOutputStream.writeBytes(parameterValue + lineEnd);
}
/**
* Write data file into header and data output stream.
*
* @param dataOutputStream data output stream handle data parsing
* @param dataFile data byte as DataPart from collection
* @param inputName name of data input
* @throws IOException
*/
private void buildDataPart(DataOutputStream dataOutputStream, DataPart dataFile, String inputName) throws IOException {
dataOutputStream.writeBytes(twoHyphens + boundary + lineEnd);
dataOutputStream.writeBytes("Content-Disposition: form-data; name=\"" +
inputName + "\"; filename=\"" + dataFile.getFileName() + "\"" + lineEnd);
if (dataFile.getType() != null && !dataFile.getType().trim().isEmpty()) {
dataOutputStream.writeBytes("Content-Type: " + dataFile.getType() + lineEnd);
}
dataOutputStream.writeBytes(lineEnd);
ByteArrayInputStream fileInputStream = new ByteArrayInputStream(dataFile.getContent());
int bytesAvailable = fileInputStream.available();
int maxBufferSize = 1024 * 1024;
int bufferSize = Math.min(bytesAvailable, maxBufferSize);
byte[] buffer = new byte[bufferSize];
int bytesRead = fileInputStream.read(buffer, 0, bufferSize);
while (bytesRead > 0) {
dataOutputStream.write(buffer, 0, bufferSize);
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable, maxBufferSize);
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
}
dataOutputStream.writeBytes(lineEnd);
}
/**
* Simple data container use for passing byte file
*/
public class DataPart {
private String fileName;
private byte[] content;
private String type;
/**
* Default data part
*/
public DataPart() {
}
/**
* Constructor with data.
*
* @param name label of data
* @param data byte data
*/
public DataPart(String name, byte[] data) {
fileName = name;
content = data;
}
/**
* Constructor with mime data type.
*
* @param name label of data
* @param data byte data
* @param mimeType mime data like "image/jpeg"
*/
public DataPart(String name, byte[] data, String mimeType) {
fileName = name;
content = data;
type = mimeType;
}
/**
* Getter file name.
*
* @return file name
*/
public String getFileName() {
return fileName;
}
/**
* Setter file name.
*
* @param fileName string file name
*/
public void setFileName(String fileName) {
this.fileName = fileName;
}
/**
* Getter content.
*
* @return byte file data
*/
public byte[] getContent() {
return content;
}
/**
* Setter content.
*
* @param content byte file data
*/
public void setContent(byte[] content) {
this.content = content;
}
/**
* Getter mime type.
*
* @return mime type
*/
public String getType() {
return type;
}
/**
* Setter mime type.
*
* @param type mime type
*/
public void setType(String type) {
this.type = type;
}
}
}
上传图片功能：
public static void uploadMultipartImage(final Bitmap bitmap, final
UploadServiceRestInf restclientinterface, final Context context) {
String url = "";
MultipartRequest multipartRequest = new
MultipartRequest(Request.Method.POST, url, new
Response.Listener<NetworkResponse>() {
@Override
public void onResponse(NetworkResponse response) {
String resultResponse = new String(response.data);
try {
JSONObject result = new JSONObject(resultResponse);
String status = result.getString("status");
String message = result.getString("message");
Log.e("UploadImageService", message);
restclientinterface.uploadStatus(message);
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
NetworkResponse networkResponse = error.networkResponse;
String errorMessage = "Unknown error";
if (networkResponse == null) {
if (error.getClass().equals(TimeoutError.class)) {
errorMessage = "Request timeout";
} else if (error.getClass().equals(NoConnectionError.class)) {
errorMessage = "Failed to connect server";
}
} else {
String result = new String(networkResponse.data);
try {
JSONObject response = new JSONObject(result);
String status = response.getString("status");
String message = response.getString("message");
Log.e("UploadImageService", "onErrorResponse : " + message);
restclientinterface.uploadStatus(message);
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}) {
@Override
public Map<String, String> getHeaders() throws AuthFailureError {
HashMap<String, String> params = getHeaderParams(context);
return params;
}
@Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<>();
return params;
}
@Override
protected Map<String, DataPart> getByteData() {
Map<String, DataPart> params = new HashMap<>();
// params.put("avatar", new DataPart("file_avatar.jpg", ImageUploadUtils.getFileDataFromBitmap(context,bitmap), "image/jpeg"));
params.put("cover", new DataPart("file_cover.jpg", ImageUploadUtils.getFileDataFromBitmap(context, bitmap), "image/jpeg"));
return params;
}
};
queue = VolleySingleton.getInstance(context).getRequestQueue();
queue.add(multipartRequest);
}
实用程序类：
/**
* Turn bitmap into byte array.
*
* @param bitmap
* @return byte array
*/
public static byte[] getFileDataFromBitmap(Context context, Bitmap bitmap) {
ByteArrayOutputStream byteArrayOutputStream = new
ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, 80, byteArrayOutputStream);
return byteArrayOutputStream.toByteArray();
}
我不明白上面的代码是否正确？文件上传功能中的getByteData()和getParams()在做什么？
如何从停止的部分继续上传图片？