将图像发送到 Web 服务器并接收信息

Question

我是 android 和 java 的新手，所以请容忍我使用不正确的术语。我正在编写一个有助于用图像识别位置的应用程序。

1. 从相机捕捉图像
2. 将捕获的图像发送到网络服务器
3. 收听和接收来自网络服务器的有关捕获图像位置的信息并显示给用户。

因此主要问题是：

• 将图片发送到网络服务器
• 从网络服务器接收信息

Answer 1

我使用这种方法（我从某个地方得到，但不知道从哪里来），它对我有用：

private void doFileUpload() {

    HttpURLConnection conn = null;
    DataOutputStream dos = null;
    DataInputStream inStream = null;
    String lineEnd = "\r\n";
    String twoHyphens = "--";
    String boundary = "*****";
    int bytesRead, bytesAvailable, bufferSize;
    byte[] buffer;
    int maxBufferSize = 1 * 1024 * 1024; //size of your image
    String responseFromServer = "";
    String urlString = "http://yourwebserver/receiver.php";

    try {
        // ------------------ CLIENT REQUEST
        FileInputStream fileInputStream = new FileInputStream(new File(
                mFileName));
        // open a URL connection to the Servlet
        URL url = new URL(urlString);
        // Open a HTTP connection to the URL
        conn = (HttpURLConnection) url.openConnection();
        // Allow Inputs
        conn.setDoInput(true);
        // Allow Outputs
        conn.setDoOutput(true);
        // Don't use a cached copy.
        conn.setUseCaches(false);
        // Use a post method.
        conn.setRequestMethod("POST");
        conn.setRequestProperty("Connection", "Keep-Alive");
        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=\"uploadedfile\";filename=\""
                + mFileName + "\"" + 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);
        // close streams
        Log.e("Debug", "File is written");
        fileInputStream.close();
        dos.flush();
        dos.close();
    } catch (MalformedURLException ex) {
        Log.e("Debug", "error: " + ex.getMessage(), ex);
    } catch (IOException ioe) {
        Log.e("Debug", "error: " + ioe.getMessage(), ioe);
    }
    // ------------------ read the SERVER RESPONSE
    try {
        inStream = new DataInputStream(conn.getInputStream());
        String str;
        while ((str = inStream.readLine()) != null) {
            Log.e("Debug", "Server Response " + str);
        }
        inStream.close();
    } catch (IOException ioex) {
        Log.e("Debug", "error: " + ioex.getMessage(), ioex);
    }
}

文件将在您的网络服务器上的 $_FILES 数组中。