Getting Started with Visa APIs in Spring Boot

Including how to set up Two-Way SSL authentication

3 min readJun 25, 2020

The following tutorial goes over how to set up Two-Way SSL authentication by sending a simple API request to https://sandbox.api.visa.com/vdp/helloworld.

Configure a Java Key Store

1. Make sure you download the 4 necessary files

Private key (can only be downloaded once during the creation of a Visa Developer project)
Project Certificate (a)
VDP Certificate (b)
DigiCert Certificate (c)

2. Follow these steps to generate a JKS file

Remember the password you will create!

Set up a Spring project

1. Initialize a project

Go to https://start.spring.io and set up the project including the Spring Web dependency

2. Create a class to store incoming data

Create a Response.java class to contain the data

package com.example.demo;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;@JsonIgnoreProperties(ignoreUnknown = true)
public class Response {  private String message;
  public Response() {}  public String getMessage() {
    return message;
  }  public void setMessage(String message) {
    this.message = message;
  }  @Override
  public String toString() {
    return "Message=" + message;
  }}

3. Update main application to fetch data

Add the .jks file and authentication credentials. Remember to update the keystore path and password, as well as user id and password!

package com.example.demo;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
import org.apache.http.client.HttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.ssl.SSLContextBuilder;
import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
import org.springframework.util.ResourceUtils;
import javax.net.ssl.SSLContext;@SpringBootApplication
public class DemoApplication {  private static final Logger log = LoggerFactory.getLogger(DemoApplication.class);  public static void main(String[] args) {
    SpringApplication.run(DemoApplication.class, args);
  }  @Bean
  public RestTemplate restTemplate(RestTemplateBuilder builder) throws Exception {
    SSLContext sslContext = SSLContextBuilder
      .create()
.loadKeyMaterial(ResourceUtils.getFile("src/main/resources/keyAndCertBundle.jks"), "password".toCharArray(), "password".toCharArray())
.loadTrustMaterial(ResourceUtils.getFile("src/main/resources/keyAndCertBundle.jks"), "password".toCharArray())
.build();    HttpClient client = HttpClients.custom()
      .setSSLContext(sslContext)
      .build();    return builder
      .requestFactory(() -> new HttpComponentsClientHttpRequestFactory(client))
      .basicAuthentication("INSERT_USER_ID", "INSERT_PASSWORD")
      .build();
  }  @Bean
  public CommandLineRunner run(RestTemplate restTemplate) throws Exception {    return args -> {
      Response res = restTemplate.getForObject("https://sandbox.api.visa.com/vdp/helloworld", Response.class);
      log.info(res.toString());
    };
  }}

4. Add dependency in `pom.xml`

Required to create an HttpClient in the RestTemplate builder

<dependency>
  <groupId>org.apache.httpcomponents</groupId
  <artifactId>httpclient</artifactId>
  <version>4.5.2</version>
</dependency>

5. Run the application

If authentication is successful, running ./mvnw spring-boot:run should print to the console