How to POST raw whole JSON in the body of a Retrofit request?

Question

This question may have been asked before but no it was not definitively answered. How exactly does one post raw whole JSON inside the body of a Retrofit request?

See

Answer 1

I wanted to compare speed of volley and retrofit for sending and receiving data I wrote below code (for retrofit part)

first dependency:

dependencies {
     implementation 'com.squareup.retrofit2:retrofit:2.4.0'
     implementation 'com.squareup.retrofit2:converter-gson:2.4.0'
}

Then interface:

 public interface IHttpRequest {

    String BaseUrl="https://example.com/api/";

    @POST("NewContract")
    Call register(@Body HashMap registerApiPayload);
}

and a function to set parameters to post data to server(In MainActivity):

private void Retrofit(){

    Retrofit retrofitRequest = new Retrofit.Builder()
            .baseUrl(IHttpRequest.BaseUrl)
            .addConverterFactory(GsonConverterFactory.create())
            .build();

    // set data to send
    HashMap SendData =new HashMap<>();
    SendData.put("token","XYXIUNJHJHJHGJHGJHGRTYTRY");
    SendData.put("contract_type","0");
    SendData.put("StopLess","37000");
    SendData.put("StopProfit","48000");

    final IHttpRequest request=retrofitRequest.create(IHttpRequest.class);

    request.register(SendData).enqueue(new Callback() {
        @Override
        public void onResponse(Call call, Response response) {
            if (response.isSuccessful()){
                Toast.makeText(getApplicationContext(),response.body().toString(),Toast.LENGTH_LONG).show();
            }
        }

        @Override
        public void onFailure(Call call, Throwable t) {

        }
    });

}

And I found Retrofit faster than volley in my case.