How to configure load balancing for RestTemplate?

1 year ago
Benjamin Taylor
1 minute

When using RestTemplate for load balancing, it is common to configure it in conjunction with Spring Cloud’s service discovery and load balancing components. Here is a simple configuration example:

  1. Add dependencies:
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-loadbalancer</artifactId>
</dependency>
  1. Create a RestTemplate Bean.
@Configuration
public class RestTemplateConfig {
    
    @LoadBalanced
    @Bean
    public RestTemplate restTemplate() {
        return new RestTemplate();
    }
}
  1. “When the @LoadBalanced annotation is used, it enables load balancing functionality for RestTemplate. RestTemplate will automatically use a service discovery component (such as Eureka) to locate instances of the target service and perform load balancing. Here is an example code snippet:”
@RestController
public class MyController {
    
    @Autowired
    private RestTemplate restTemplate;
    
    @GetMapping("/test")
    public String test() {
        ResponseEntity<String> response = restTemplate.getForEntity("http://my-service/api/test", String.class);
        return response.getBody();
    }
}

In the example above, RestTemplate will use a service discovery component to locate a service instance named “my-service” and make a load-balanced call. If there are multiple instances, RestTemplate will choose one instance based on the load-balancing algorithm.

bannerAds