SpringCloud笔记05 OpenFeign服务消费者
coconutnut
 2020-04-21 09:36:57      

https://blog.csdn.net/ThinkWon/article/details/103735751

Spring Cloud OpenFeign 是声明式的服务调用工具，它整合了Ribbon和Hystrix，拥有负载均衡和服务容错功能

创建feign-service模块

依赖

教程给的依赖是

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<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-web</artifactId>
</dependency>

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

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

换成consul注册中心，改成

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<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-web</artifactId>
</dependency>

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

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

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

发现没有spring cloud版本和依赖管理，加上

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<spring-cloud.version>Hoxton.RELEASE</spring-cloud.version>
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<dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-dependencies</artifactId>
      <version>${spring-cloud.version}</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
  </dependencies>
</dependencyManagement>

查看右侧Maven栏中没有红线

下一步

配置

教程给的配置

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server:
  port: 8701

spring:
  application:
    name: feign-service

eureka:
  client:
    register-with-eureka: true
    fetch-registry: true
    service-url:
      defaultZone: http://localhost:8001/eureka/

换成consul

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#eureka:
#  client:
#    register-with-eureka: true
#    fetch-registry: true
#    service-url:
#      defaultZone: http://localhost:8001/eureka/

cloud:
  consul:
    host: localhost
    port: 8500
    discovery:
      service-name: ${spring.application.name}

@EnableFeignClients启动功能

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@EnableFeignClients
@EnableDiscoveryClient
@SpringBootApplication
public class FeignServiceApplication {

    public static void main(String[] args) {
        SpringApplication.run(FeignServiceApplication.class, args);
    }

}

接口和控制器

根据源码补齐其它代码

负载均衡

启动consul服务器，两个user-service，feign-service服务

调用http://localhost:8701/user/1四次

交替打印

服务降级

前面UserFallbackService也拷过来了

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@FeignClient(value = "user-service", fallback = UserFallbackService.class)
public interface UserService {
}

注释也加了

修改application.yml，开启Hystrix功能

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#在Feign中开启Hystrix
feign:
  hystrix:
    enabled: true

关闭两个user-service服务，重新启动feign-service

调用http://localhost:8701/user/1进行测试

发现被降级

日志打印功能

用FeignConfig配置类

在application.yml中配置需要开启日志的Feign客户端

可设置日志级别

总结