【问题标题】:Reduce the size of image before uploading on Java server android在上传到 Java 服务器 android 之前减小图像的大小
【发布时间】:2016-02-03 08:09:18
【问题描述】:

我想将大图像的大小减少到 2 MB,但我没有做到这一点我从谷歌搜索了很多材料,但我无法解决我的问题。 这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;
    }
}

【问题讨论】:

  • 我在上述实现中没有看到任何表明您已尝试缩小正在上传的位图的任何内容。
  • 试试这个Link
  • int maxBufferSize = 2 * 1024 * 1024;我已将大小固定为 2 MB,之后我使用了 Math.min 函数,该函数从 bytesAvailablemaxBufferSize 中选择最小大小
  • 威胁是duplicatedHere 是我的解决方案

标签: java android


【解决方案1】:

尝试使用this Java 图像处理

【讨论】:

    【解决方案2】:

    我在新项目中也遇到了这个问题。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,再次将位图放回文件中,上传到服务器。以下是两种方法

    /**
     * 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;
    }
    

    【讨论】:

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