2factor SMS in Spring Boot App

plugins {
    id 'org.springframework.boot' version '2.3.0.RELEASE'
    id 'io.spring.dependency-management' version '1.0.9.RELEASE'
    id 'java'
}

group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '11'

repositories {
    mavenCentral()
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-web'
    testImplementation('org.springframework.boot:spring-boot-starter-test') {
        exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
    }
}

test {
    useJUnitPlatform()
}

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.net.http.HttpClient;

@Configuration
public class HttpClientConfig {

    @Bean
    public HttpClient createClient() {
        HttpClient client = HttpClient.newBuilder()
                .version(HttpClient.Version.HTTP_2)
                .followRedirects(HttpClient.Redirect.NORMAL)
                .build();
        return client;
    }
}

@Service
class Scratch (private val httpClient: HttpClient) {

    fun sendSms() {
        val apiKey = "<insert your api key here>"
        val data: MutableMap<String, String> = HashMap()
        data["To"] = "mobile"
        data["From"] = "SHUNYA"
        data["TemplateName"] = "TEMPLATE-NAME"
        data["VAR1"] = "1234"
        data["VAR2"] = "testhash"

        val request: HttpRequest = HttpRequest.newBuilder()
                .POST(ofFormData(data))
                .uri(URI.create("https://2factor.in/API/V1/$apiKey/ADDON_SERVICES/SEND/TSMS"))
                .header("User-Agent", "Java 11 HttpClient")
                .header("Content-Type", "application/x-www-form-urlencoded")
                .build()
        val response: HttpResponse<String> = httpClient.send(request, HttpResponse.BodyHandlers.ofString())

        println(response.statusCode())
        println(response.body())
    }

    fun ofFormData(data: Map<String, String>): BodyPublisher? {
        val builder = StringBuilder()
        for ((key, value) in data) {
            if (builder.isNotEmpty()) {
                builder.append("&")
            }
            builder.append(URLEncoder.encode(key, StandardCharsets.UTF_8))
            builder.append("=")
            builder.append(URLEncoder.encode(value, StandardCharsets.UTF_8))
        }
        return HttpRequest.BodyPublishers.ofString(builder.toString())
    }

}

@Configuration
class OkHttpConfig {

    @Bean
    fun okHttpClient(): OkHttpClient {
        return OkHttpClient.Builder()
                .readTimeout(60, TimeUnit.SECONDS)
                .writeTimeout(60, TimeUnit.SECONDS)
                .addInterceptor(HttpLoggingInterceptor())
                .build()
    }
}

class Scratch (private val okHttpClient: OkHttpClient){

    fun sendSms() {
        try {
            val apiKey = "<insert API key here>"
            val build = MultipartBody.Builder()
                    .setType(MultipartBody.FORM)
                    .addFormDataPart("To", "mobile")
                    .addFormDataPart("From", "SHUNYA")
                    .addFormDataPart("TemplateName", "TEMPLATE-NAME")
                    .addFormDataPart("VAR1", otp)
                    .build()
            val request = Request.Builder()
                    .url("https://2factor.in/API/V1/$apiKey/ADDON_SERVICES/SEND/TSMS")
                    .post(build)
                    .build()

            okHttpClient.newCall(request).execute().use { response ->
                if (!response.isSuccessful) {
                    logger.warn("Error sending SMS {}", response.body?.string())
                    throw IOException("Unexpected code $response")
                }
                logger.info("SMS Status - {}", response.body?.string())
            }
        } catch (e: Exception) {
            logger.warn("Error sending SMS", e)
            throw e
        }
    }
}

fun getPromoBalance() {
    val restTemplate= RestTemplate()
    val responseEntity = restTemplate.exchange("http://2factor.in/API/V1/$apiKey/ADDON_SERVICES/BAL/PROMOTIONAL_SMS", HttpMethod.GET, HttpEntity.EMPTY, String::class.java)
    if (responseEntity.statusCode.is2xxSuccessful) {
        val body = responseEntity.body
        logger.info("Promotional SMS Balance is {}", body)
    }
}