9.OpenFeign服务接口调用

学习B站尚硅谷周阳老师SpringCloud的听课笔记

1. 概述 1.1 OpenFeign是什么？

Feign是一个声明式的web服务客户端，让编写web服务客户端变得非常容易，只需创建一个接口并在接口上添加注解即可

GitHub：https://github.com/spring-cloud/spring-cloud-openfeign

1.2 能干嘛

1.3Feign和OpenFeign两者区别

2.OpenFeign使用步骤 2.1 新建cloud-consumer-feign-order80

Feign在消费端使用
接口+注解 微服务调用接口+@FeignClient

2.2 改pom

    
        cloud2020
        com.atguigu.springcloud
        1.0-SNAPSHOT
    
    4.0.0

    cloud-consumer-feign-order80

    
    
        
            org.springframework.cloud
            spring-cloud-starter-openfeign
        
        
            org.springframework.cloud
            spring-cloud-starter-netflix-eureka-client
        
        
            com.atguigu.springcloud
            cloud-api-common
            ${project.version}
        
        
            org.springframework.boot
            spring-boot-starter-web
        

        
            org.springframework.boot
            spring-boot-starter-actuator
        

        
            org.springframework.boot
            spring-boot-devtools
            runtime
            true
        

        
            org.projectlombok
            lombok
            true
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
        
    

2.3改yml

server:
  port: 80
eureka:
  client:
    register-with-eureka: false
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka, http://eureka7002.com:7002/eureka

2.4 主启动类标注注解@EnableFeignClients

@SpringBootApplication
@EnableFeignClients
public class OrderFeignMain80 {
    public static void main(String[] args) {
        SpringApplication.run(OrderFeignMain80.class,args);
    }
}

2.5 业务类

业务逻辑接口+@FeignClient配置调用provider服务

新建PaymentFeignService接口并新增注解@FeignClient

@Component
@FeignClient(value = "CLOUD-PAYMENT-SERVICE")
public interface PaymentFeignService {

    @GetMapping(value = "/payment/get/{id}")
    public CommonResult getPaymentById(@PathVariable("id") Long id);
}

@RestController
public class OrderFeignController {

    @Resource
    private PaymentFeignService paymentFeignService;

    @GetMapping(value = "/consumer/payment/get/{id}")
    public CommonResult getPaymentById(@PathVariable("id") Long id){
       return paymentFeignService.getPaymentById(id);
    }
}

2.6 测试

先启动2个eureka集群7001/7002，再启动2个微服务8001/8002，启动OpenFeign启动

http://localhost/consumer/payment/get/3

Feign自带负载均衡配置项

总结：

3.OpenFeign超时控制和日志打印功能 3.1超时控制

OpenFeign默认等待一秒钟，超过后报错

OpenFeign默认支持Ribbon

YML文件里需要开启OpenFeign客户端超时控制，即ribbon的超时控制

ribbon:
  ReadTimeout:  5000 # 建立连接后从服务器读取可用资源所用的时间
  ConnectTimeout: 5000 #建立连接需要的时间，适用于网络状况正常的情况下，两端连接所用的时间

3.2日志打印

日志级别：

写配置类

@Configuration
public class FeignConfig {
    @Bean
    Logger.Level feignLoggerLevel(){
        return Logger.Level.FULL;
    }
}

改yml

logging:
  level:
    com.atguigu.springcloud.service.PaymentFeignService: debug

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