我没有使用 Retrofit 2.+ 的经验，但是在 Retrofit 1.9 中发送json以POST请求中的String的身份发送到服务器，我***将其封装在TypedJsonString

I have no experience with Retrofit 2.+, but in Retrofit 1.9 to send json to server as a String in a POST request I have been forced to envelop it in TypedJsonString

import retrofit.mime.TypedString;

public class TypedJsonString extends TypedString {
    public TypedJsonString(String body) {
        super(body);
    }

    @Override public String mimeType() {
        return "application/json";
    }
}

并使用此接口定义:

@POST(BASE_METHOD)
Response postProductRequest(@Body TypedJsonString productRequest); 

从后台线程发出请求:

String requestBody = new Gson().toJson(new ProductRequest());
retrofit.client.Response r = mApiService.postProductRequest(new TypedJsonString(requestBody));