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 = {}. ", helloUri.toString());
        return new RestTemplate().getForEntity(helloUri, String.class).getBody();
    }
}