AndroidでHTTP POSTリクエストでrailsのAPIサーバにmultipartで画像を送るときはFileBodyではなくFileInputStreamを使う

表題の通り。
FileBodyで送ると、UTF8を指定してもなぜか画像のデータが文字化けして送られるので
railsからInvalid byte sequence in utf8が返ってくる。

参考：
https://groups.google.com/forum/#!topic/android-sdk-japan/zi-voNmjC6k
http://d.hatena.ne.jp/gszsato/20110701/1309532723

参考コード
https://github.com/shohei/GhFabLab/blob/master/src/com/example/ghfablab/AsyncHttpRequest.java

	public void post(String url,String name, String quantity, String location, String note, String image_filepath) {
        HttpClient httpClient = new DefaultHttpClient();
        HttpContext localContext = new BasicHttpContext();
        //HttpPost httpPost = new HttpPost(url);
        HttpPost httpPost = new HttpPost("http://192.168.1.100:3000/products");
        httpPost.addHeader("content_type","image/jpeg");
        try {
        	MultipartEntity multipartEntity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE,null,Charset.forName("UTF-8"));
        	//MultipartEntity multipartEntity = new MultipartEntity();
        	multipartEntity.addPart("product[name]", new StringBody(name,Charset.forName("UTF-8")));
        	multipartEntity.addPart("product[quantity]", new StringBody(quantity,Charset.forName("UTF-8")));
        	multipartEntity.addPart("product[location]", new StringBody(location,Charset.forName("UTF-8")));
        	multipartEntity.addPart("product[note]", new StringBody(note,Charset.forName("UTF-8")));
        	
        	File imgFile = new File(image_filepath);
        	//FileBody fileBody = new FileBody(imgFile.getAbsoluteFile(), "image/jpeg");
        	//FileBody fileBody = new FileBody(imgFile, "image/jpeg","UTF-8");
               //#########Filebodyは使わない##################
    	       //FileBody fileBody = new FileBody(imgFile, "application/octet-stream","UTF-8");
        	

        	FileInputStream in = new FileInputStream(imgFile);
                //#########InputStreamBodyを使いましょう##################        	
                InputStreamBody streamBody = new InputStreamBody(in, "image/jpeg","shutter_plugin_sample.jpg");
        	//multipartEntity.addPart("product[photo]", fileBody);
        	multipartEntity.addPart("product[photo]", streamBody);
        	
        	//UrlEncodedFormEntity ent = new UrlEncodedFormEntity((List<? extends NameValuePair>) multipartEntity,HTTP.UTF_8);
        	httpPost.setEntity(multipartEntity);
        	//httpPost.setEntity(ent);
        	HttpResponse response = httpClient.execute(httpPost, localContext);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }