Spring Boot Hystrix

Producer service

User the below version of spring boot

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
    <version>2.2.6.RELEASE</version>
</dependency>

Controller class

@RestController
public class WelcomeController {
 
    @RequestMapping("/greeting")
    public String greeting(@PathVariable("username") String username) throws Exception {
    	if(username.equalsIgnoreCase("abc")){
    		throw new Exception();
    	}
        return "Hello, " + username;
    }
}

Application properties file

server.port=9090
spring.application.name=rest-producer

Consumer Service with hystrix

pom.xml

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-hystrix</artifactId>
    <version>1.4.7.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
    <version>2.2.6.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-thymeleaf</artifactId>
    <version>2.2.6.RELEASE</version>
</dependency>

Service Class

@Service
public class GreetingService {
    @HystrixCommand(fallbackMethod = "defaultGreeting")
    public String getGreeting(String username) {
        return new RestTemplate()
          .getForObject("http://localhost:9090/greeting/{username}", 
          String.class, username);
    }
 
    private String defaultGreeting(String username) {
        return "Hello User!";
    }
}

Spring boot application class

@SpringBootApplication
@EnableCircuitBreaker
public class RestConsumerApplication {
    public static void main(String[] args) {
        SpringApplication.run(RestConsumerApplication.class, args);
    }
}

RestController class

@RestController
public class GreetingController {
 
    @Autowired
    private GreetingService greetingService;
 
    @GetMapping("/get-greeting/{username}")
    public String getGreeting(@PathVariable("username") String username) {
        String msg = greetingService.getGreeting(username);
        return msg;
    }
}