🌐 What is a REST Client?

A REST Client is used to call another REST API from your Spring Boot app — just like your browser makes a request to a website, your app can make requests to other services.

✅ Common Use Case

Imagine your app needs weather data from another service — instead of building your own, you just call a public API using a REST client.

🧰 Types of REST Clients in Spring Boot

  1. RestTemplate (older, still used)
  2. WebClient (modern, reactive and non-blocking)

💡 Using RestTemplate (Simple Example)

1. Add Bean in Configuration:

@Bean
public RestTemplate restTemplate() {
    return new RestTemplate();
}

2. Use It in Your Service:

@Autowired
RestTemplate restTemplate;

 

public String getQuote() {
    String url = "https://api.quotable.io/random";
    return restTemplate.getForObject(url, String.class);
}

✅ getForObject() makes a GET request and returns the response as a string (or object).

⚡ Using WebClient (Modern & Non-blocking)

1. Add Dependency (if not already):

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-webflux</artifactId>
</dependency>

2. Example Usage:

WebClient webClient = WebClient.create();

 

String response = webClient.get()
    .uri("https://api.quotable.io/random")
    .retrieve()
    .bodyToMono(String.class)
    .block();

  • bodyToMono() converts the response to a reactive type.
  • .block() is used to wait and get the result (for non-reactive projects).

🔐 Bonus: Handling Headers, POST, and Auth

You can easily add headers, POST data, or use auth tokens with both clients.

✅ Why Use REST Clients?

  • To call external APIs
  • Communicate between microservices
  • Perform GET, POST, PUT, DELETE operations
Back to blog

Leave a comment