Retrofit 2.0 - How to get response body for 400 Bad Request error?

Question

So when I make a POST API call to my server, I get a 400 Bad Request error with JSON response.

{
    \"userMessage\": \"Blah\",
    \"internalMessage\": \"Bad Re         


        

Answer 1

First step:

Create your POJO class for error response. In my case, ApiError.java

public class ApiError {

    @SerializedName("errorMessage")
    @Expose
    private String errorMessage;

    public String getErrorMessage() {
        return errorMessage;
    }

    public void setErrorMessage(String errorMessage) {
        this.errorMessage= errorMessage;
    }
}

Second Step:

Write below code in your api callback.

Call.enqueue(new Callback<RegistrationResponse>() {
     @Override
     public void onResponse(Call<RegistrationResponse> call, Response<RegistrationResponse> response) 
     {
         if (response.isSuccessful()) {
             // do your code here
         } else if (response.code() == 400) {
             Converter<ResponseBody, ApiError> converter =
                            ApiClient.retrofit.responseBodyConverter(ApiError.class, new Annotation[0]);

                    ApiError error;

                    try {
                        error = converter.convert(response.errorBody());
                        Log.e("error message", error.getErrorMessage());
                        Toast.makeText(context, error.getErrorMessage(), Toast.LENGTH_LONG).show();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
         }
     }

     @Override
     public void onFailure(Call<RegistrationResponse> call, Throwable t) {
         //do your failure handling code here
     }
}

Here ApiClient.retrofit is your retrofit instance which is static.

Answer 2

Handle ErrorResponse with your class object

Kotlin

val errorResponse = Gson().fromJson(response.errorBody()!!.charStream(), ErrorResponse::class.java)

Java

ErrorResponse errorResponse = new Gson().fromJson(response.errorBody.charStream(),ErrorResponse.class)

Answer 3

You can try the below code to get 400 response. You can get error response from errorBody() method.

Call.enqueue(new Callback<ResponseBody>() {
    @Override
    public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
        //get success and error response here
 if (response.code() == 400) {
                if(!response.isSuccessful()) {
                    JSONObject jsonObject = null;
                    try {
                        jsonObject = new JSONObject(response.errorBody().string());
                        String userMessage = jsonObject.getString("userMessage");
                        String internalMessage = jsonObject.getString("internalMessage");
                        String errorCode = jsonObject.getString("errorCode");
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                }
            }

    @Override
    public void onFailure(Call<ResponseBody> call, Throwable t) {
        //get failure response here
    }
}
}

EDIT: Fixed method name from toString to string