public void setHeaders(URLConnection connection, HTTPSamplerBase sampler) throws IOException {
        // Get the encoding to use for the request
        String contentEncoding = sampler.getContentEncoding();
        long contentLength = 0L;
        HTTPFileArg[] files = sampler.getHTTPFiles();

        // Check if we should do a multipart/form-data or an
        // application/x-www-form-urlencoded post request
        if(sampler.getUseMultipart()) {
            // Set the content type
            connection.setRequestProperty(
                    HTTPConstants.HEADER_CONTENT_TYPE,
                    HTTPConstants.MULTIPART_FORM_DATA + "; boundary=" + getBoundary()); // $NON-NLS-1$

            // Write the form section
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            OutputStreamWriter osw = new OutputStreamWriter(bos, contentEncoding);
            // Add any parameters
            for (JMeterProperty jMeterProperty : sampler.getArguments()) {
                HTTPArgument arg = (HTTPArgument) jMeterProperty.getObjectValue();
                String parameterName = arg.getName();
                if (arg.isSkippable(parameterName)) {
                    continue;
                }
                // Write multipart for parameter
                writeFormMultipart(osw, contentEncoding, parameterName, arg.getValue(), sampler.getDoBrowserCompatibleMultipart());
            }
            osw.flush();
            // Keep the content, will be sent later
            formDataPostBody = bos.toByteArray();
            contentLength = formDataPostBody.length;

            // Now we just construct any multipart for the files
            // We only construct the file multipart start, we do not write
            // the actual file content
            for (int i = 0; i < files.length; i++) {
                bos.reset();
                contentLength += multipartDividerBytes.length + CRLF.length;
                HTTPFileArg file = files[i];
                // Write multipart for file
                writeStartFileMultipart(osw, contentEncoding, file.getPath(), file.getParamName(), file.getMimeType());
                osw.flush();
                // Technically speaking, we should refrain from decoding the header to string
                // since we will have to encode it again when sending the request
                // However, HTTPFileArg#setHeaer(byte[]) does not exist yet
                String header = bos.toString(contentEncoding);
                // If this is not the first file we can't write its header now
                // for simplicity we always save it, even if there is only one file
                file.setHeader(header);
                contentLength += bos.size();
                // Add also the length of the file content
                File uploadFile = new File(file.getPath());
                contentLength += uploadFile.length();
                contentLength += CRLF.length;
            }

            // Add the end of multipart
            contentLength += multipartDividerBytes.length + DASH_DASH_BYTES.length + CRLF.length;

            // Set the content length
            connection.setRequestProperty(HTTPConstants.HEADER_CONTENT_LENGTH, Long.toString(contentLength));

            // Make the connection ready for sending post data
            connection.setDoOutput(true);
            connection.setDoInput(true);
        }
        else {
            // Check if the header manager had a content type header
            // This allows the user to specify their own content-type for a POST request
            String contentTypeHeader = connection.getRequestProperty(HTTPConstants.HEADER_CONTENT_TYPE);
            boolean hasContentTypeHeader = contentTypeHeader != null && contentTypeHeader.length() > 0;

            // If there are no arguments, we can send a file as the body of the request
            if(sampler.getArguments() != null && sampler.getArguments().getArgumentCount() == 0 && sampler.getSendFileAsPostBody()) {
                // we're sure that there is one file because of
                // getSendFileAsPostBody method's return value.
                HTTPFileArg file = files[0];
                if(!hasContentTypeHeader) {
                    // Allow the mimetype of the file to control the content type
                    if(file.getMimeType() != null && file.getMimeType().length() > 0) {
                        connection.setRequestProperty(HTTPConstants.HEADER_CONTENT_TYPE, file.getMimeType());
                    }
                    else {
                        if(HTTPAbstractImpl.ADD_CONTENT_TYPE_TO_POST_IF_MISSING) {
                            connection.setRequestProperty(HTTPConstants.HEADER_CONTENT_TYPE, HTTPConstants.APPLICATION_X_WWW_FORM_URLENCODED);
                        }
                    }
                }
                // Create the content length we are going to write
                File inputFile = new File(file.getPath());
                contentLength = inputFile.length();
            }
            else {
                // We create the post body content now, so we know the size
                ByteArrayOutputStream bos = new ByteArrayOutputStream();

                // If none of the arguments have a name specified, we
                // just send all the values as the post body
                String postBody = null;
                if(!sampler.getSendParameterValuesAsPostBody()) {
                    // Set the content type
                    if(!hasContentTypeHeader && HTTPAbstractImpl.ADD_CONTENT_TYPE_TO_POST_IF_MISSING) {
                        connection.setRequestProperty(HTTPConstants.HEADER_CONTENT_TYPE, HTTPConstants.APPLICATION_X_WWW_FORM_URLENCODED);
                    }

                    // It is a normal post request, with parameter names and values
                    postBody = sampler.getQueryString(contentEncoding);
                }
                else {
                    // Allow the mimetype of the file to control the content type
                    // This is not obvious in GUI if you are not uploading any files,
                    // but just sending the content of nameless parameters
                    // TODO: needs a multiple file upload scenario
                    if(!hasContentTypeHeader) {
                        HTTPFileArg file = files.length > 0? files[0] : null;
                        if(file != null && file.getMimeType() != null && file.getMimeType().length() > 0) {
                            connection.setRequestProperty(HTTPConstants.HEADER_CONTENT_TYPE, file.getMimeType());
                        }
                        else {
                            if(HTTPAbstractImpl.ADD_CONTENT_TYPE_TO_POST_IF_MISSING) {
                                connection.setRequestProperty(HTTPConstants.HEADER_CONTENT_TYPE, HTTPConstants.APPLICATION_X_WWW_FORM_URLENCODED);
                            }
                        }
                    }

                    // Just append all the parameter values, and use that as the post body
                    StringBuilder postBodyBuffer = new StringBuilder();
                    for (JMeterProperty jMeterProperty : sampler.getArguments()) {
                        HTTPArgument arg = (HTTPArgument) jMeterProperty.getObjectValue();
                        postBodyBuffer.append(arg.getEncodedValue(contentEncoding));
                    }
                    postBody = postBodyBuffer.toString();
                }

                bos.write(postBody.getBytes(contentEncoding));
                bos.flush();
                bos.close();

                // Keep the content, will be sent later
                formDataUrlEncoded = bos.toByteArray();
                contentLength = bos.toByteArray().length;
            }

            // Set the content length
            connection.setRequestProperty(HTTPConstants.HEADER_CONTENT_LENGTH, Long.toString(contentLength));

            // Make the connection ready for sending post data
            connection.setDoOutput(true);
        }
    }
@Test
    public void testSetHeaders_NoFilename() throws IOException {
        sampler.setMethod(HTTPConstants.POST);
        setupNoFilename(sampler);
        setupFormData(sampler);

        postWriter.setHeaders(connection, sampler);
        checkNoContentType(connection);
        checkContentLength(connection, "title=mytitle&description=mydescription".length());
    }