Check out example codes for "request.getreader()". It will help you in understanding the concepts better.

Code Example 1

IOUtils.toString(request.getReader())

Code Example 2

// Read from request
    StringBuilder buffer = new StringBuilder();
    BufferedReader reader = request.getReader();
    String line;
    while ((line = reader.readLine()) != null) {
        buffer.append(line);
    }
    String data = buffer.toString()

Code Example 3

public static String getBody(HttpServletRequest request) throws IOException {

    String body = null;
    StringBuilder stringBuilder = new StringBuilder();
    BufferedReader bufferedReader = null;

    try {
        InputStream inputStream = request.getInputStream();
        if (inputStream != null) {
            bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
            char[] charBuffer = new char[128];
            int bytesRead = -1;
            while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
                stringBuilder.append(charBuffer, 0, bytesRead);
            }
        } else {
            stringBuilder.append("");
        }
    } catch (IOException ex) {
        throw ex;
    } finally {
        if (bufferedReader != null) {
            try {
                bufferedReader.close();
            } catch (IOException ex) {
                throw ex;
            }
        }
    }

    body = stringBuilder.toString();
    return body;
}

Learn ReactJs, React Native from akashmittal.com