SpringCloud-Feign学习笔记

1.服务消费者pom.xml文件引入依赖

 
        
            org.springframework.cloud
            spring-cloud-starter-netflix-eureka-client
        
        
            org.springframework.cloud
            spring-cloud-starter-openfeign
        
    

此处用的openFeign,为springCloud对feign的封装，加了对springMvc注解的支持

2.启动类加上@EnableFeignClients注解

@SpringBootApplication
@EnableFeignClients
public class AutoApplication9001 {
    public static void main(String[] args) {
        SpringApplication.run(AutoApplication9001.class,args);
    }
}

3.添加接口，面向接口编程,接口方法是服务提供方提供的接口方法

@FeignClient(name = "find",fallback = CallBackImpl.class,path = "/resume")
//@RequestMapping("/resume")
public interface FindService {

    @GetMapping("/openstate/{userId}")
    Integer findOneById(@PathVariable("userId") Long userId);
}

4.回退方法类,定义回退方法要开启hystrix

import org.springframework.stereotype.Component;

@Component
public class CallBackImpl implements FindService{
    @Override
    public Integer findOneById(Long userId) {
        return -6;
    }
}

feign:
  hystrix:
    enabled: true

hystrix:
  command:
    default:
      execution:
        isolation:
          thread:
            timeoutInMilliseconds: 9000

5.Fegin默认请求处理超时时长1s，可以配置ribbon,会以ribbon的为准

find:
  ribbon:
    #请求连接超时时间
    ConnectTimeout: 2000
    #请求处理超时时间
    ReadTimeout: 15000
    #对所有操作都进⾏重试
    OkToRetryOnAllOperations: true
    MaxAutoRetries: 0 #对当前选中实例重试次数，不包括第⼀次调⽤
    MaxAutoRetriesNextServer: 0 #切换实例的重试次数
    NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RoundRobinRule #负载策略调整

6.Ribbon和Hystrix的请求超时时长都设置了，以最小的为准

7.Feign对请求压缩和响应压缩的支持

feign:
  compression:
    request:
      enabled: true
      mime-types: text/html,application/xml,application/json # 设置压缩的数据类型，此处也是默认值
      min-request-size: 2048 # 设置触发压缩的⼤⼩下限，此处也是默认值
    response:
      enabled: true

8.Feign日志级别设置

@Configuration
public class FeignConfig {

    @Bean
    Logger.Level feignLevel() {
        return Logger.Level.FULL;
    }
}

logging:
 level:
 # Feign⽇志只会对⽇志级别为debug的做出响应
 controller.service.feginService: debug