spring cloud之ribbon/openFeign

 

 

 

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
eureka该jar中已集成ribbon，无需在引用，若非引用也无碍

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
</dependency>

 

 

代码如下
@Configuration
public class ApplicationContextConfig {

    @Bean
    @LoadBalanced
    public RestTemplate getRestTemplate(){
        return  new RestTemplate();
    }
}

 

 

修改ribbon负载均衡策略（默认轮询）--配置不能被被@ComponentScan扫描（@SpringBootApplication中包含@ComponentScan）

1随机

代码如下

@Configuration
public class MySelfRule {

    @Bean
    public IRule myRule(){
        //TODO 定义为随机
        return new RandomRule();
    }

}

 手写轮询算法

 

 

 代码如下

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

 

 

@Component
public class MyLB implements LoadBalancer {

    private AtomicInteger atomicInteger = new AtomicInteger(0);

    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("*****************第几次访问次数**next:"+next);
        return next;
    }

    @Override
    public ServiceInstance instances(List<ServiceInstance> serviceInstances) {

        int index = getAndIncrement() % serviceInstances.size();

        return serviceInstances.get(index);
    }
}

测试---手写轮询算法

@Resource
private LoadBalancer loadBalancer;

@Resource
private DiscoveryClient discoveryClient;

@GetMapping("/consumer/lb/{id}")
public CommonResult<Payment> getPaymentLB(@PathVariable("id") long id){
    List<ServiceInstance> instances = discoveryClient.getInstances("CLOUD-PAYMENT-SERVECE");
    if (instances == null || instances.size() <= 0){
        return null;
    }
    ServiceInstance serviceInstance = loadBalancer.instances(instances);
    URI uri = serviceInstance.getUri();
    return restTemplate.getForObject(uri+"/payment/getPaymentById/"+id,CommonResult.class);

}

测试结果

{"code":200,"message":"成功","data":null}

openfeign使用

openfeign = rubbon+restTemplate （openfeign 的使用更符合我们的编码习惯）

使用

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>

服务端接口 B

 

 

 客户端A

 

 

 

 

 

 

在启动类上加@EnableFeignClients
调用 http://localhost/order-feign/getPaymentById/1
结果 {"code":200,"message":"success","data":{"code":200,"message":"成功","data":{"id":1,"serial":"22222"}}

openfeign超时控制（默认1s）

ribbon:
  ReadTimeout: 5000
  ConnectTimeout: 5000

openfeign日志增强

 

 logging:

  level:
    com.atgugu.springcloud.service.PaymentFeignService: debug

查看控制台日志

--->GET http://CLOUD-PAYMENT-SERVECE/payment/getPaymentById/1 HTTP/1.1
---> END HTTP (0-byte body)
<--- HTTP/1.1 200 (5038ms)
connection: keep-alive
content-type: application/json
date: Thu, 04 Jun 2020 09:14:48 GMT
keep-alive: timeout=60
transfer-encoding: chunked