在我的App Engine后端，我有一个方法可以从Google Cloud Storage
@ApiMethod(
name = "getProfileImage",
path = "image",
httpMethod = ApiMethod.HttpMethod.GET)
public Image getProfileImage(@Named("imageName")String imageName){
try{
HttpTransport httpTransport = GoogleNetHttpTransport.newTrustedTransport();
GoogleCredential credential = GoogleCredential.getApplicationDefault();
Storage.Builder storageBuilder = new Storage.Builder(httpTransport,new JacksonFactory(),credential);
Storage storage = storageBuilder.build();
Storage.Objects.Get getObject = storage.objects().get("mybucket", imageName);
ByteArrayOutputStream out = new ByteArrayOutputStream();
// If you're not in AppEngine, download the whole thing in one request, if possible.
getObject.getMediaHttpDownloader().setDirectDownloadEnabled(false);
getObject.executeMediaAndDownloadTo(out);
byte[] oldImageData = out.toByteArray();
out.close();
ImagesService imagesService = ImagesServiceFactory.getImagesService();
return ImagesServiceFactory.makeImage(oldImageData);
}catch(Exception e){
logger.info("Error getting image named "+imageName);
}
return null;
}
我遇到的问题是当我在Android应用程序中调用图像数据时如何获取图像数据？
由于您无法从应用引擎返回原语，因此我将其转换为Image，以便我可以在我的应用中调用getImageData()来获取字节[]。
然而，返回到应用程序的Image对象与app引擎中的Image对象不同，因此没有getImageData（）。
如何将图像数据传输到我的Android应用程序？
如果我创建一个其中包含byte []变量的Object，那么我将byte []变量设置为字符串数据并从该方法返回该对象将起作用吗？
更新
图像从Android应用程序发送。 （这段代码可能正确也可能不正确，我还没有调试过它）
@WorkerThread
public String startResumableSession(){
try{
File file = new File(mFilePath);
long fileSize = file.length();
file = null;
String sUrl = "https://www.googleapis.com/upload/storage/v1/b/lsimages/o?uploadType=resumable&name="+mImgName;
URL url = new URL(sUrl);
HttpURLConnection urlConnection = (HttpURLConnection)url.openConnection();
urlConnection.setRequestProperty("Authorization","");
urlConnection.setRequestProperty("X-Upload-Content-Type","image/png");
urlConnection.setRequestProperty("X-Upload-Content-Length",String.valueOf(fileSize));
urlConnection.setRequestMethod("POST");
if(urlConnection.getResponseCode() == HttpURLConnection.HTTP_OK){
return urlConnection.getHeaderField("Location");
}
}catch(Exception e){
e.printStackTrace();
}
return null;
}
private long sendNextChunk(String sUrl,File file,long skip){
int bytesRead, bytesAvailable, bufferSize;
byte[] buffer;
int maxBufferSize = 524287;
long totalBytesSent = 0;
try{
long fileSize = file.length();
FileInputStream fileInputStream = new FileInputStream(file);
skip = fileInputStream.skip(skip);
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable, maxBufferSize);
totalBytesSent = skip + bufferSize;
buffer = new byte[bufferSize];
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
try {
while (bytesRead > 0) {
try {
URL url = new URL(sUrl);
HttpURLConnection urlConnection = (HttpURLConnection)url.openConnection();
urlConnection.setDoInput(true);
urlConnection.setDoOutput(true);
urlConnection.setUseCaches(false);
urlConnection.setChunkedStreamingMode(524287);
urlConnection.setRequestMethod("POST");
urlConnection.setRequestProperty("Connection", "Keep-Alive");
urlConnection.setRequestProperty("Content-Type","image/png");
urlConnection.setRequestProperty("Content-Length",String.valueOf(bytesRead));
urlConnection.setRequestProperty("Content-Range", "bytes "+String.valueOf(skip)+"-"+String.valueOf(totalBytesSent)+"/"+String.valueOf(fileSize));
DataOutputStream outputStream = new DataOutputStream(urlConnection.getOutputStream());
outputStream.write(buffer, 0, bufferSize);
int code = urlConnection.getResponseCode();
if(code == 308){
String range = urlConnection.getHeaderField("Range");
return Integer.parseInt(range.split("-")[1]);
}else if(code == HttpURLConnection.HTTP_CREATED){
return -1;
}
outputStream.flush();
outputStream.close();
outputStream = null;
} catch (OutOfMemoryError e) {
e.printStackTrace();
// response = "outofmemoryerror";
// return response;
return -1;
}
fileInputStream.close();
}
} catch (Exception e) {
e.printStackTrace();
// response = "error";
// return response;
return -1;
}
}catch(Exception e){
e.printStackTrace();
}
return -1;
}
编辑2：
显然我不清楚我在Android应用程序中使用端点
答案 0 :(得分：1)
我最终做了什么/发现你需要使用端点调用api调用execute()并返回从API传回的实际数据
例如
api调用返回Image
public Image getProfileImage(@Named("id") long id, @Named("imageName")String imageName){
try{
ProfileRecord pr = get(id);
HttpTransport httpTransport = GoogleNetHttpTransport.newTrustedTransport();
GoogleCredential credential = GoogleCredential.getApplicationDefault();
Storage.Builder storageBuilder = new Storage.Builder(httpTransport,new JacksonFactory(),credential);
Storage storage = storageBuilder.build();
Storage.Objects.Get getObject = storage.objects().get("mybucket", imageName);
ByteArrayOutputStream out = new ByteArrayOutputStream();
// If you're not in AppEngine, download the whole thing in one request, if possible.
getObject.getMediaHttpDownloader().setDirectDownloadEnabled(false);
getObject.executeMediaAndDownloadTo(out);
byte[] oldImageData = out.toByteArray();
out.close();
return ImagesServiceFactory.makeImage(oldImageData);
}catch(Exception e){
logger.info("Error getting image named "+imageName);
}
return null;
}
然后在客户端我会这样称之为
Image i = pr.profileImage(id,"name.jpg").execute();
byte[] data = i.decodeImageData();
答案 1 :(得分：-1)
您可以使用Google Cloud Endpoints：
Google Cloud Endpoints包含工具，库和功能 允许您从App生成API和客户端库 引擎应用程序，称为API后端，用于简化客户端 访问其他应用程序的数据。端点使其更容易 为Web客户端和移动客户端创建Web后端，例如 Android或Apple的iOS。