springcloud ribbon搭建服务负载均衡

加入ribbon依赖：<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-ribbon</artifactId>
</dependency>在启动器中加入：@SpringBootApplication
@EnableEurekaClient
public class OrderApplication {
public static void main(String[] args) {
SpringApplication.run(OrderApplication.class, args);
}

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

RestTemplate

中我们增加了一个

@LoadBalanced

注解，该注解就是能够让

RestTemplate

启用客户端负载均衡。
启动eureka服务器，启动多个service
访问资源，输出端口号，会发现端口号交替出现，则测试成功

 直接使用Ribbon的API

另外，除了使用

@LoadBalanced

注解外，我们还可以直接使用Ribbon所提供的

LoadBalancerClient

来实现负载均衡：

@RestController
public class HelloController {
protected Logger logger = LoggerFactory.getLogger(HelloController.class);

@Autowired
private RestTemplate restTemplate;

@Autowired
private LoadBalancerClient loadBalancerClient;

@RequestMapping(value = "/hello", method = RequestMethod.GET)
public String hello() {
return restTemplate.getForEntity("http://SERVICE-HELLO/hello", String.class).getBody();
}

@RequestMapping(value = "/helloEx", method = RequestMethod.GET)
public String helloEx() {
ServiceInstance instance = this.loadBalancerClient.choose("SERVICE-HELLO");
URI helloUri = URI.create(String.format("http://%s:%s/hello", instance.getHost(), instance.getPort()));
logger.info("Target service uri =
4000
{}. ", helloUri.toString());
return new RestTemplate().getForEntity(helloUri, String.class).getBody();
}
}