SpringCloud中的Ribbon负载均衡详细解读

	@Autowired
	DiscoveryClient discoveryClient;
	
	AtomicInteger atomicInteger = new AtomicInteger();
	
	@GetMapping("/client7")
	public Object client7() {
		
		
		List<ServiceInstance> instances = discoveryClient.getInstances("provider");
		
		
		// 随机
		int nextInt = new Random().nextInt(instances.size());
		
	
		// 自定义轮训算法
		int i = atomicInteger.getAndIncrement();
		instances.get(i % instances.size());
		
		// 权重。。
		for (ServiceInstance serviceInstance : instances) {
			//	int quanzhong = 	serviceInstance.getMetadata(); // 权重  1-9
		
		}
		ServiceInstance instance = instances.get(nextInt);
		
		// ribbon 完成客户端的负载均衡，过滤掉down了的节点
		//	ServiceInstance instance = lb.choose("provider");
		
		String url ="http://" + instance.getHost() +":"+ instance.getPort() + "/getHi";
		   
		String respStr = restTemplate.getForObject(url, String.class);

		return respStr;
	}

	//使用ribbon，添加@LoadBalance，使RestTemplate具备负载均衡能力。
	@Bean
	@LoadBalanced
	public RestTemplate restTemplate() {
		return new RestTemplate();
	}
	
	@Autowired
	private RestTemplate restTemplate;
	//serviceName=虚拟主机名。默认情况下，虚拟主机名和服务名一致。
	String url = "http://"+serviceName+"/send/alisms-template";
	//调用
	ResponseEntity<ResponseResult> resultEntity = restTemplate.postForEntity(url, smsSendRequest, ResponseResult.class);
	

	//测试根据serviceName获取服务提供者信息。此时不需要@LoadBalance，默认是轮训。
	@Autowired
	private LoadBalancerClient loadBalancerClient;
	// 不能将choseServiceName和 restTemplate写在一起，因为后者中已经有前者了。
	@GetMapping("/choseServiceName")
	public ResponseResult choseServiceName() {
		String serviceName = "service-sms";
		ServiceInstance si = loadBalancerClient.choose(serviceName);
		System.out.println("sms节点信息：url:"+si.getHost()+",port:"+si.getPort());
		
		return ResponseResult.success("");
	}

@Bean
	public IRule myRule(){
		//return new RoundRobinRule();
		//return new RandomRule();
		return new RetryRule(); 

provider.ribbon.NFLoadBalancerRuleClassName=com.netflix.loadbalancer.RandomRule

ribbon.NFLoadBalancerRuleClassName=com.netflix.loadbalancer.RandomRule

ribbon.eureka.enabled=false
ribbon.listOfServers=localhost:80,localhost:81