java - 无法在android中通过JSON将base64字符串图像发送到asp.net web服务

Question

我在 ASP.net 中创建了一个 RESTful 的 Web 服务。我想从 Android 应用程序使用这些服务。基本上我使用 Android 的默认库发送请求并获取 JSON 格式的响应。

这是我的代码:

public class PostImagesHandler {
    final static String TAG = "WebHandlerHttpPost";
    Context context;
    ImagesBean imageBean;

    public String postImagesRequest(String URL, Context context,
            ImagesBean imgBean) {
        this.context = context;
        String result = null;
        this.imageBean = imgBean;

        try {
            HttpPost request = new HttpPost(URL);
            System.out.println("WHAT IS URL :: " + URL);
            request.setHeader("Accept", "application/json");
            request.setHeader("Content-type", "application/json");
            request.addHeader("Cache-Control", "no-cache, no-store, must-revalidate"); // HTTP 1.1.
            request.addHeader("Pragma", "no-cache"); // HTTP 1.0.
            request.addHeader("Expires", "0"); // Proxies.


                     Bitmap bm = BitmapFactory.decodeFile("sdcard/dotTest9.jpg");
             ByteArrayOutputStream baos = new ByteArrayOutputStream();
             bm.compress(Bitmap.CompressFormat.JPEG, 90, baos);
             byte[] bytes_ = baos.toByteArray();

            String image_str = Base64.encodeToString(readFile().getBytes(),
                    Base64.NO_WRAP);
            appendLog(image_str);

            JSONStringer userJson = new JSONStringer().object()
            .key("objPostSectionImages").object().key("ID")
            .value("1").key("SUB_ID").value("1").key("MainTaskId")
            .value("1").key("ImageBase64").value(image_str)
            .key("actualAuditDate").value(getCurrentDateTime()).endObject()
             endObject();


            Log.d(TAG, "SECTION IMAGE STRING :: " + userJson.toString());

            StringEntity entity = new StringEntity(userJson.toString(), "UTF-8");
            entity.setContentEncoding(new BasicHeader(HTTP.CONTENT_TYPE,
                    "application/json"));
            entity.setContentType("application/json");
            request.setEntity(entity);

            HttpParams params = new BasicHttpParams();
            HttpConnectionParams.setConnectionTimeout(params, 30000);
            HttpConnectionParams.setSoTimeout(params, 10000);

            // Send request to WCF service
            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpResponse response = httpClient.execute(request);

            if (response != null) {
                StringBuilder sb = new StringBuilder();
                BufferedReader rd = new BufferedReader(new InputStreamReader(
                        response.getEntity().getContent()));

                String line;
                while ((line = rd.readLine()) != null) {
                    sb.append(line + "\n");
                }

                result = sb.toString();
                Log.d(TAG, "AUDIT SECTION IMAGES Response: " + result);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }

    public void appendLog(String text) {
        File logFile = new File("sdcard/dotTest7.txt");
        if (!logFile.exists()) {
            try {
                logFile.createNewFile();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        try {
            // BufferedWriter for performance, true to set append to file flag
            BufferedWriter buf = new BufferedWriter(new FileWriter(logFile,
                    true));
            buf.append(text);
            // buf.newLine();
            buf.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    @SuppressLint("SimpleDateFormat")
    public static String getCurrentDateTime() {
        return new SimpleDateFormat("MM-dd-yyyy").format(Calendar.getInstance()
                .getTime());
    }
}

我可以通过这种方式发送小图像，但在发送大图像(超过 5 KB)时，我遇到了问题。有时我会收到“请求错误”，有时它会起作用。

Answer 1

也许您的 ASP.NET Web 服务会转义 base64 字符串中的正斜杠？这使得该数据从正常应用程序的角度来看被破坏了。

在小图像中，base64 转换后获得 / 符号的概率明显低于大图像，因此您会遇到这种随机错误情况。

您可以检查服务结果字符串中是否有 /\ 符号，并将其替换为 / 并检查它是否有效。