Spring Boot Several Ways to Call External Interfaces

In the microservice architecture, calls between services are indispensable. Spring Boot provides developers with a variety of ways to achieve this task, and this article will introduce you in detail.

1. Use RestTemplate

RestTemplateIt is a commonly used REST client in early Spring Boot versions, although in the new Spring version,RestTemplateIt has been marked as not recommended, but it is still necessary to understand its usage. Here's how to use itRestTemplateExample of making GET and POST requests.

Sample code

import ;
import ;
import ;
import ;

// REST GET requestRestTemplate restTemplate = new RestTemplate();
String resultGet = ("/endpoint", );

// REST POST requestHttpHeaders headers = new HttpHeaders();
("Custom-Header", "Custom header value");
HttpEntity<String> entity = new HttpEntity<>(headers);
String resultPost = ("/endpoint", entity, );

2. Use WebClient

WebClientIs it launched in Spring 5 for alternativesRestTemplateThe new non-blocking REST client.

Sample code

import ;

// Create a WebClientWebClient webClient = ("");

// REST GET requestString resultGet = ()
        .uri("/endpoint")
        .retrieve()
        .bodyToMono()
        .block();

// REST POST requestString resultPost = ()
        .uri("/endpoint")
        .header("Custom-Header", "Custom header value")
        .retrieve()
        .bodyToMono()
        .block();

3. Use Feign

To simplify calls between microservices, Spring Cloud provides Feign. Feign makes calling from an HTTP client as simple as calling a local method.

Sample code

import ;
import ;
import ;

// Define Feign interface@FeignClient(name = "example-service", url = "")
public interface ExampleClient {
    @GetMapping("/endpoint")
    String exampleRequest();
}

// Call Feign interface@Autowired
private ExampleClient exampleClient;

public void doSomething() {
    String result = ();
}

Conclusion

The above briefly introduces the three ways Spring Boot calls external interfaces, but in practice, it is necessary to choose based on the specific requirements and actual situation of the project to ensure optimal project orientation and efficiency. For more related Spring Boot calling external interfaces, please search for my previous articles or continue browsing the related articles below. I hope everyone will support me in the future!