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android – Upload multipart image data in JSON with Retrofit?

Posted by: admin June 15, 2020 Leave a comment


I would like to do a PUT request with this JSON body (containing a picture) and with Retrofit. I’m using it under Android:

    "Request": {
        "data": {
            "Key": "keydata",
            "param": {
                "title": "Testingpostmultipartimageupload",
                "photo": **"IMAGE BYTE DATA"**

Any clues?

How to&Answers:

Ok, I found a solution using multipart, somethings like that:

void modifyPic(
    @Header("auth_token") String token,
    @Path("id") int userid,
    @Part("request[data][param][title]") String title,
    @Part("request[data][param][Photo]") TypedFile avatar,
    Callback<User> cb


You need to put image data in byte by using multipart form data.

try {
    HttpPost httppost = new HttpPost("some url");
    MultipartEntity multipartEntity = 
        new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE);  
    multipartEntity.addPart("Image", new FileBody(image));
    mHttpClient.execute(httppost, new YOURHANDLER());
} catch (Exception e) {
    Log.e(ServerCommunication.class.getName(), e.getLocalizedMessage(), e);

To send post request using parameters

HttpPost httpPost = new HttpPost(url);
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();

if (values != null) {
    for (Map.Entry<String, String> entry : values.entrySet()) {
            new BasicNameValuePair(entry.getKey(), entry.getValue()));
    httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs, "UTF-8"));


Retrofit only takes multipart and requestbody for its multipart.

Call<SubmitLevel1Part2IconResp> loadLevel1halfIconswithImage(@Part("headerdata[relation][icon_type]") RequestBody icon_type, @Part("headerdata[relation][name]") RequestBody name, @Part MultipartBody.Part file);

And then in java

 // MultipartBody.Part is used to send also the actual filename
 MultipartBody.Part body =  MultipartBody.Part.createFormData("headerdata[relation][relative_image]", fileUpload.getName(), requestFile);

call = service.loadLevel1halfIconswithImage(icon_type, name, body);