在Java服务器android上上载之前减小图像大小

我想将大图像的大小减少到2MB，但我没有做到。我从谷歌搜索了很多资料，但我无法解决我的问题。 下面是我正在使用的代码，它以实际大小上传图像，但我想减小图像的大小

public int uploadFile(final String sourceFileUri) {

    String fileName = sourceFileUri;

    HttpURLConnection conn = null;
    DataOutputStream dos = null;
    String lineEnd = "\r\n";
    String twoHyphens = "--";
    String boundary = "*****";
    int bytesRead, bytesAvailable, bufferSize;
    byte[] buffer;
    int maxBufferSize = 2 * 1024 * 1024;
    File sourceFile = new File(sourceFileUri);

    if (!sourceFile.isFile()) {

        dialog.dismiss();

        Log.e("uploadFile", "Source File not exist :" + filepath);

        runOnUiThread(new Runnable() {
            public void run() {
                messageText.setText("Source File not exist :" + filepath);
            }
        });

        return 0;

    } else {
        try {
            FileInputStream fileInputStream = new FileInputStream(
                    sourceFile);
            URL url = new URL(upLoadServerUri);
            conn = (HttpURLConnection) url.openConnection();
            conn.setDoInput(true); // Allow Inputs
            conn.setDoOutput(true); // Allow Outputs
            conn.setUseCaches(false); // Don't use a Cached Copy
            conn.setRequestMethod("POST");
            conn.setRequestProperty("Connection", "Keep-Alive");
            conn.setRequestProperty("ENCTYPE", "multipart/form-data");
            conn.setRequestProperty("Content-Type",
                    "multipart/form-data;boundary=" + boundary);

            dos = new DataOutputStream(conn.getOutputStream());
            dos.writeBytes(twoHyphens + boundary + lineEnd);
            dos.writeBytes("Content-Disposition: form-data; name=\"uploaded_file\";filename=\"" + fileName+ "\"" + lineEnd);
            dos.writeBytes(lineEnd);

            // create a buffer of maximum size
            bytesAvailable = fileInputStream.available();

            bufferSize = Math.min(bytesAvailable, maxBufferSize);
            buffer = new byte[bufferSize];

            // read file and write it into form...
            bytesRead = fileInputStream.read(buffer, 0, bufferSize);

            while (bytesRead > 0) {

                dos.write(buffer, 0, bufferSize);
                bytesAvailable = fileInputStream.available();
                bufferSize = Math.min(bytesAvailable, maxBufferSize);
                bytesRead = fileInputStream.read(buffer, 0, bufferSize);

            }

            // send multipart form data necesssary after file data...
            dos.writeBytes(lineEnd);
            dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);

            // Responses from the server (code and message)
            serverResponseCode = conn.getResponseCode();
            String serverResponseMessage = conn.getResponseMessage();

            Log.i("uploadFile", "HTTP Response is : "
                    + serverResponseMessage + ": " + serverResponseCode);

            if (serverResponseCode == 200) {

                runOnUiThread(new Runnable() {
                    public void run() {
                        String msg = "File Upload Completed.";
                        messageText.setText(msg);
                        Toast.makeText(UpLoadImage.this,
                                "File Upload Complete.", Toast.LENGTH_SHORT)
                                .show();
                    }
                });
            }

            // close the streams //
            fileInputStream.close();
            dos.flush();
            dos.close();

        } catch (MalformedURLException ex) {

            dialog.dismiss();
            ex.printStackTrace();

            runOnUiThread(new Runnable() {
                public void run() {
                    messageText
                            .setText("MalformedURLException Exception : check script url.");
                    Toast.makeText(UpLoadImage.this,
                            "MalformedURLException", Toast.LENGTH_SHORT)
                            .show();
                }
            });

            Log.e("Upload file to server", "error: " + ex.getMessage(), ex);
        } catch (Exception e) {

            dialog.dismiss();
            e.printStackTrace();

            runOnUiThread(new Runnable() {
                public void run() {
                    messageText.setText("Got Exception : see logcat ");
                    Toast.makeText(UpLoadImage.this,
                            "Got Exception  : see logcat ",
                            Toast.LENGTH_SHORT).show();
                }
            });
            Log.e("Upload file Exception",
                    "Exception : " + e.getMessage(), e);
        }
        dialog.dismiss();
        return serverResponseCode;
    }
}

---

尝试Java图像处理

在我的新项目中，我也面临着这个问题。我要解决的是：从文件中解码位图，减小位图大小，并在需要时旋转它，将位图重新放入文件中，上传到服务器。下面是两种方法

/**
 * Resize to avoid using too much memory showLoading big images (e.g.: 2560*1920)
 **/
private static Bitmap getImageResized(Context context, Uri selectedImage) {
    Bitmap bm = null;
    int[] sampleSizes = new int[]{5, 3, 2, 1};
    int i = 0;
    do {
        bm = decodeBitmap(context, selectedImage, sampleSizes[i]);
        Log.d(TAG, "resizer: new bitmap width = " + bm.getWidth());
        i++;
    } while (bm.getWidth() < minWidthQuality && i < sampleSizes.length);
    return bm;
}


 public static Uri getUriFromResult(Context context, int resultCode, Intent imageReturnedIntent) {
    File imageFile = getTempFile(context);
    Uri selectedImage;
    if (resultCode == Activity.RESULT_OK) {
        boolean isCamera = (imageReturnedIntent == null ||
                imageReturnedIntent.getData() == null ||
                imageReturnedIntent.getData().equals(Uri.fromFile(imageFile)));
        if (isCamera) {
            Bitmap bm;
            selectedImage = Uri.fromFile(imageFile);
            bm = getImageResized(context, selectedImage);

            try {
                FileOutputStream outStream = new FileOutputStream(imageFile);
                bm.compress(Bitmap.CompressFormat.PNG, 50, outStream);
                outStream.flush();
                outStream.close();
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                bm.recycle();
            }
            return Uri.fromFile(imageFile);
        } else {
            return imageReturnedIntent.getData();
        }
    }
    return null;
}

/**
*调整大小以避免使用过多内存加载大图像（例如：2560*1920）
**/
私有静态位图getImageResized（上下文上下文，Uri selectedImage）{
位图bm=null；
int[]sampleSizes=新的int[]{5,3,2,1}；
int i=0；
做{
bm=解码位图（上下文，选择图像，采样[i]）；
Log.d（标记“resizer:new bitmap width=“+bm.getWidth（））；
i++；
}而（bm.getWidth（）

在上面的实现中，我没有看到任何显示您试图缩小正在上载的位图的内容。请尝试使用int-maxBufferSize=2*1024*1024；我已将大小固定为2MB，然后使用Math.min函数从bytesAvailable和maxBufferSizeIt中选择最小大小threat is but是我的解决方案