Spring Boot Load Balancing Guide

1 year ago
Jackson Davis
2 minutes

In Spring Boot, implementing load balancing is often achieved by integrating with Spring Cloud Ribbon. Ribbon is an integration library for load balancer and client-side HTTP clients, which can be used with Spring Cloud Eureka for service discovery and load balancing.

To implement load balancing using Ribbon in Spring Boot, you first need to add the necessary dependencies in the project’s pom.xml file.

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
</dependency>

Next, you need to add the @EnableEurekaClient annotation in the main class of the application to enable Eureka client functionality. Then, you can achieve load balancing by annotating the RestTemplate Bean with @LoadBalanced.

@SpringBootApplication
@EnableEurekaClient
public class MyApplication {

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

    public static void main(String[] args) {
        SpringApplication.run(MyApplication.class, args);
    }
}

Then, you can use RestTemplate to send HTTP requests, and Ribbon will automatically handle load balancing.

@RestController
public class MyController {

    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/hello")
    public String hello() {
        String result = restTemplate.getForObject("http://example-service/hello", String.class);
        return result;
    }
}

In the mentioned example, example-service is the name of the service, and Ribbon will select specific instances based on the service’s name for load balancing. Therefore, load balancing can be achieved by deploying multiple instances of the same service.

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