Java 移动后端启动程序-上载到AppEngine Blobstore

如何使用Mobile Backend Starter或Google Cloud Endpoints将文件从Android上传到Google App Engine Blobstore？

与Mobile Backend Starter共享我的到期日

要获取上传和下载URL，您需要将这两个方法添加到

CloudBackend.java

类中，以便从活动中访问URL：

public String getUploadBlobURL(String bucketName, String path, String accessMode) {

        String url = null;
        try {
            url = getMBSEndpoint().blobEndpoint()
                    .getUploadUrl(bucketName, path, accessMode).execute()
                    .getShortLivedUrl();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return url;
    }

public String getDownloadBlobURL(String bucketName, String path) {

        String url = null;
        try {
            url = getMBSEndpoint().blobEndpoint()
                    .getDownloadUrl(bucketName, path).execute()
                    .getShortLivedUrl();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return url;
    }

然后，在标准客户端库的帮助下，您可以使用URL将字节流传输到Google云存储

下面我将给你一些例子来说明如何使用它们

要将文件上载到Google云存储，您可以使用类似的方法：

活动

File fileUp = new File(Environment.getExternalStorageDirectory(), fileName);
        new AsyncBlobUploader(this, mProcessingFragment.getCloudBackend()).execute(fileUp);

File fileDown = new File(Environment.getExternalStorageDirectory(),
                fileName); //file to create
        new AsyncBlobDownloader(imageView, mProcessingFragment.getCloudBackend())
            .execute(fileDown);

异步任务

public class AsyncBlobUploader extends AsyncTask<File, Void, String> {
    private Context context;
    private ProgressDialog pd;
    private CloudBackend cb;

    public AsyncBlobUploader(Context context, CloudBackend cb) {
        this.context = context;
        this.cb = cb;
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pd = ProgressDialog.show(context, null,
                "Loading... Please wait...");
        pd.setProgressStyle(ProgressDialog.STYLE_SPINNER);
        pd.setIndeterminate(true);
        pd.setCancelable(true);
        pd.show();
    }

    protected String doInBackground(File... files) {
        File file = files[0];
        String uploadUrl = cb.getUploadBlobURL(bucketName, file.getName(),"PUBLIC_READ_FOR_APP_USERS");
        String url = uploadUrl.split("&Signature")[0]; // url without Signature

        HttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new HttpPost(url);

        FileBody filebody = new FileBody(file,ContentType.create(getMimeType(file
                .toString())), file.getName());

        MultipartEntityBuilder multipartEntity = MultipartEntityBuilder.create();        
        multipartEntity.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
        multipartEntity.addPart("file", filebody);
        httppost.setEntity(multipartEntity.build());
        System.out.println( "executing request " + httppost.getRequestLine( ) );
        try {
            HttpResponse response = httpclient.execute( httppost );
            Log.i("response", response.getStatusLine().toString());
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        httpclient.getConnectionManager( ).shutdown( );

        return (String) uploadUrl;
    }

    protected void onPostExecute(String result) {

        pd.dismiss();
        Log.d("BlobUrl", result);

    }

    public static String getMimeType(String url) {
        String type = null;
        String extension = MimeTypeMap.getFileExtensionFromUrl(url);
        if (extension != null) {
            MimeTypeMap mime = MimeTypeMap.getSingleton();
            type = mime.getMimeTypeFromExtension(extension);
        }
        return type;
    }
}

public class AsyncBlobDownloader extends AsyncTask<File, Integer, File> {
    private ImageView imageView;
    private ProgressDialog pd;
    private CloudBackend cb;

    public AsyncBlobDownloader(ImageView imageView, CloudBackend cb) {
        this.imageView = imageView;
        this.cb = cb;
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pd = ProgressDialog.show(imageView.getContext(), null,
                "Loading... Please wait...");
        pd.setProgressStyle(ProgressDialog.STYLE_SPINNER);
        pd.setCancelable(true);
        pd.show();
    }

    protected File doInBackground(File... files) {
        File file = files[0];
        String downloadUrl = cb.getDownloadBlobURL(bucketName,
                file.getName());
        InputStream input = null;
        OutputStream output = null;
        HttpURLConnection connection = null;
        try {
            URL url = new URL(downloadUrl);
            connection = (HttpURLConnection) url.openConnection();
            connection.connect();
            if (connection.getResponseCode() != HttpURLConnection.HTTP_OK) {
                Log.i("Response",
                        "Server returned HTTP " + connection.getResponseCode()
                                + " " + connection.getResponseMessage());
            }
            int fileLength = connection.getContentLength();

            input = connection.getInputStream();
            output = new FileOutputStream(file);

            byte data[] = new byte[4096];

            int count;
            while ((count = input.read(data)) != -1) {
                if (isCancelled()) {
                    input.close();
                    return null;
                }
                output.write(data, 0, count);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (output != null)
                    output.close();
                if (input != null)
                    input.close();
            } catch (IOException ignored) {
            }

            if (connection != null)
                connection.disconnect();
        }    
        return file;
    }

    protected void onPostExecute(File result) {    
        pd.dismiss();
        imageView.setImageURI(Uri.fromFile(result));   
    }   
}

异步任务

public class AsyncBlobUploader extends AsyncTask<File, Void, String> {
    private Context context;
    private ProgressDialog pd;
    private CloudBackend cb;

    public AsyncBlobUploader(Context context, CloudBackend cb) {
        this.context = context;
        this.cb = cb;
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pd = ProgressDialog.show(context, null,
                "Loading... Please wait...");
        pd.setProgressStyle(ProgressDialog.STYLE_SPINNER);
        pd.setIndeterminate(true);
        pd.setCancelable(true);
        pd.show();
    }

    protected String doInBackground(File... files) {
        File file = files[0];
        String uploadUrl = cb.getUploadBlobURL(bucketName, file.getName(),"PUBLIC_READ_FOR_APP_USERS");
        String url = uploadUrl.split("&Signature")[0]; // url without Signature

        HttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new HttpPost(url);

        FileBody filebody = new FileBody(file,ContentType.create(getMimeType(file
                .toString())), file.getName());

        MultipartEntityBuilder multipartEntity = MultipartEntityBuilder.create();        
        multipartEntity.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
        multipartEntity.addPart("file", filebody);
        httppost.setEntity(multipartEntity.build());
        System.out.println( "executing request " + httppost.getRequestLine( ) );
        try {
            HttpResponse response = httpclient.execute( httppost );
            Log.i("response", response.getStatusLine().toString());
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        httpclient.getConnectionManager( ).shutdown( );

        return (String) uploadUrl;
    }

    protected void onPostExecute(String result) {

        pd.dismiss();
        Log.d("BlobUrl", result);

    }

    public static String getMimeType(String url) {
        String type = null;
        String extension = MimeTypeMap.getFileExtensionFromUrl(url);
        if (extension != null) {
            MimeTypeMap mime = MimeTypeMap.getSingleton();
            type = mime.getMimeTypeFromExtension(extension);
        }
        return type;
    }
}

public class AsyncBlobDownloader extends AsyncTask<File, Integer, File> {
    private ImageView imageView;
    private ProgressDialog pd;
    private CloudBackend cb;

    public AsyncBlobDownloader(ImageView imageView, CloudBackend cb) {
        this.imageView = imageView;
        this.cb = cb;
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pd = ProgressDialog.show(imageView.getContext(), null,
                "Loading... Please wait...");
        pd.setProgressStyle(ProgressDialog.STYLE_SPINNER);
        pd.setCancelable(true);
        pd.show();
    }

    protected File doInBackground(File... files) {
        File file = files[0];
        String downloadUrl = cb.getDownloadBlobURL(bucketName,
                file.getName());
        InputStream input = null;
        OutputStream output = null;
        HttpURLConnection connection = null;
        try {
            URL url = new URL(downloadUrl);
            connection = (HttpURLConnection) url.openConnection();
            connection.connect();
            if (connection.getResponseCode() != HttpURLConnection.HTTP_OK) {
                Log.i("Response",
                        "Server returned HTTP " + connection.getResponseCode()
                                + " " + connection.getResponseMessage());
            }
            int fileLength = connection.getContentLength();

            input = connection.getInputStream();
            output = new FileOutputStream(file);

            byte data[] = new byte[4096];

            int count;
            while ((count = input.read(data)) != -1) {
                if (isCancelled()) {
                    input.close();
                    return null;
                }
                output.write(data, 0, count);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (output != null)
                    output.close();
                if (input != null)
                    input.close();
            } catch (IOException ignored) {
            }

            if (connection != null)
                connection.disconnect();
        }    
        return file;
    }

    protected void onPostExecute(File result) {    
        pd.dismiss();
        imageView.setImageURI(Uri.fromFile(result));   
    }   
}

公共类AsyncBlobDownloader扩展了AsyncTask{
私人影像视图；
私营部门；
私有云计算；
公共异步BlobDownloader（ImageView ImageView，CloudBackend cb）{
this.imageView=imageView；
this.cb=cb；
}
@凌驾
受保护的void onPreExecute（）{
super.onPreExecute（）；
pd=ProgressDialog.show（imageView.getContext（），null，
“正在加载…请稍候…”）；
pd.setProgressStyle（ProgressDialog.STYLE_微调器）；
pd.可设置可取消（真）；
pd.show（）；
}
受保护文件doInBackground（文件…文件）{
文件=文件[0]；
String downloadUrl=cb.getDownloadBlobURL（bucketName，
getName（））；
InputStream输入=null；
OutputStream输出=null；
HttpURLConnection=null；
试一试{
URL=新URL（下载URL）；
connection=（HttpURLConnection）url.openConnection（）；
connection.connect（）；
if（connection.getResponseCode（）！=HttpURLConnection.HTTP\u确定）{
Log.i（“响应”，
“服务器返回HTTP”+连接。getResponseCode（）
+“”+连接。getResponseMessage（））；
}
int fileLength=connection.getContentLength（）；
输入=连接。getInputStream（）；
输出=新文件输出流（文件）；
字节数据[]=新字节[4096]；
整数计数；
而（（计数=输入。读取（数据））！=-1）{
如果（isCancelled（））{
input.close（）；
返回null；
}
输出.写入（数据，0，计数）；
}
}捕获（例外e）{
e、 printStackTrace（）；
}最后{
试一试{
if（输出！=null）
output.close（）；
如果（输入！=null）
input.close（）；
}捕获（忽略IOException）{
}
if（连接！=null）
连接断开（）；
}    
返回文件；
}
受保护的void onPostExecute（文件结果）{
pd.解散（）；
setImageURI（Uri.fromFile（result））；
}   
}

注意：要使用谷歌云存储，您需要启用计费。您还需要在GCS中创建bucket