springcloud中Ribbon和RestTemplate实现服务调用与负载均衡

这篇文章主要介绍了Ribbon和RestTemplate实现服务调用与负载均衡,想了解负载均衡的同学可以参考下

文件目录结构

文件目录结构很重要，特别注意的是rule文件要放在主启动类上一级位置，才能够扫描。

写pom

   org.springframework.bootspring-boot-starter-web org.springframework.bootspring-boot-starter-actuator org.projectlomboklomboktrue org.springframework.bootspring-boot-starter-testtest org.springframework.cloudspring-cloud-starter-netflix-eureka-client

因为eureka的依赖已经整合了ribbon的依赖，所以不用额外引入新的东西。

改yml

 server: port: 80 spring: application: name: cloud-book-consumer eureka: client: register-with-eureka: false fetch-registry: true service-url: defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka

主启动

 @SpringBootApplication @EnableEurekaClient @RibbonClient(name = "CLOUD-BOOK-SERVICE", configuration = LoadBalanceRule.class)   //更换轮询算法 public class RestTemplateMain80 { public static void main(String[] args) { SpringApplication.run(RestTemplateMain80.class,args); } }

业务逻辑

rules层

在图示文件目录下新建LoadBalanceRule.class，用于更换负载均衡算法。

 @Configuration public class LoadBalanceRule { @Bean public IRule iRule() { // 定义为随机 return new RandomRule(); } }

config层

开启restTemplate负载均衡
在config文件夹下创建LoadBalanceConfig.class

 @Configuration public class LoadBalanceConfig { @Bean @LoadBalanced            //开启负载均衡 public RestTemplate getReatTemplate(){ return new RestTemplate(); } }

controller层

新建BookController.class
写业务代码

 @RestController @Slf4j public class BookController { @Resource private RestTemplate restTemplate; public static final String PAYMENT_URL = "http://CLOUD-BOOK-SERVICE"; @GetMapping(value = "restTemplate/book/getAllBooks")//只要json数据时 public CommonResult getAllBooks(){ return restTemplate.getForObject(PAYMENT_URL+"/book/getAllBooks",CommonResult.class); } @GetMapping("restTemplate/book/getAllBooks2")    //需要知道更多数据时，使用getForEntity方法 public CommonResult getAllBooks2(){ ResponseEntity resultResponseEntit = restTemplate.getForEntity(PAYMENT_URL+"/book/getAllBooks",CommonResult.class); if (resultResponseEntit.getStatusCode().is2xxSuccessful()){ log.info(resultResponseEntit.getStatusCode()+"\t"+resultResponseEntit.getHeaders()); return resultResponseEntit.getBody(); }else { return new CommonResult<>(444,"操作失败"); } } @GetMapping(value = "restTemplate/book/index") public String index() { return restTemplate.getForObject(PAYMENT_URL+"/book/index",String.class); } }

使用restTemplate+Ribboin实现服务调用和负载均衡完成。

手写Ribbon负载均衡算法 lb层

1.新建LoadBalancer接口，添加代码

 public interface LoadBalancer { ServiceInstance instances(List serviceInstances); }

2.新建实现类MyLB

 @Component public class MyLB implements LoadBalancer { private AtomicInteger atomicInteger = new AtomicInteger(0); //求第几次访问  自旋锁思想 public final int getAndIncrement(){ int current; int next; do { current = this.atomicInteger.get(); next = current >=2147483647 ? 0 : current+1; }while(!this.atomicInteger.compareAndSet(current,next)); System.out.println("***第几次访问next->"+next); return next; } //负载均衡算法,实现roundRobin算法 @Override public ServiceInstance instances(List serviceInstances) { int index = getAndIncrement() % serviceInstances.size(); return serviceInstances.get(index); } }

修改BookController

 @RestController @Slf4j public class BookController { @Resource private RestTemplate restTemplate; @Resource private LoadBalancer loadBalancer; @Resource private DiscoveryClient discoveryClient; public static final String PAYMENT_URL = "http://CLOUD-BOOK-SERVICE"; @GetMapping(value = "restTemplate/book/getAllBooks")//只要json数据时 public CommonResult getAllBooks(){ List instances = discoveryClient.getInstances("CLOUD-BOOK-SERVICE"); if (instances == null || instances.size() <= 0){ return null; } ServiceInstance serviceInstance = loadBalancer.instances(instances); URI uri = serviceInstance.getUri(); return restTemplate.getForObject(uri+"/book/getAllBooks",CommonResult.class); } @GetMapping(value = "restTemplate/book/index") public String index() { List instances = discoveryClient.getInstances("CLOUD-BOOK-SERVICE"); if (instances == null || instances.size() <= 0){ return null; } ServiceInstance serviceInstance = loadBalancer.instances(instances); URI uri = serviceInstance.getUri(); return restTemplate.getForObject(uri+"/book/index",String.class); } }