SpringCloud基础教程-Feign

参考博客: Springboot 整合 SpringCloud组件-Feign(Ribbon/Hystrix) （三）
由于SpringCloud版本不同，上述文档中feign开启hystrix失效!
参考博客: Spring Cloud 之五：Feign使用Hystrix

相关配置项

入口启动类

package com.mumu.springcloud_feign;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.hystrix.EnableHystrix;
import org.springframework.cloud.netflix.hystrix.dashboard.EnableHystrixDashboard;
import org.springframework.cloud.openfeign.EnableFeignClients;

@EnableEurekaClient
@EnableDiscoveryClient
@EnableHystrix
@EnableHystrixDashboard
@EnableFeignClients
@SpringBootApplication
public class SpringcloudFeignApplication {

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

}

yml配置文件

eureka:
  instance:
    preferIpAddress: true
    instance-id: ${spring.cloud.client.ip-address}:${server.port}
  client:
    serviceUrl:
      defaultZone: http://localhost:8080/eureka/
server:
  port: 8765

spring:
  application:
    name: feign
feign:
#  hystrix的配置此处不生效！可能由于springCloud版本的原因，启用`circuitbreaker`开启熔断
#  hystrix:
#    enabled: true
  circuitbreaker:
    enabled: true

pom配置文件

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.7.12</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.mumu</groupId>
    <artifactId>springcloud_feign</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springcloud_feign</name>
    <description>springcloud_feign</description>
    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>2021.0.7</spring-cloud.version>
    </properties>
    <dependencies>

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

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
            <version>2.2.1.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix-dashboard</artifactId>
            <version>2.2.1.RELEASE</version>
        </dependency>


        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <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>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

代码相关类

Feign - Service方法接口

package com.mumu.springcloud_feign.service;


import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;

//@FeignClient(value = "client-01",fallback = SchedualServiceHiHystric.class)
@FeignClient(value = "client-01",fallbackFactory = SchedualServiceHiHystricFacotry.class)
@Component
public interface SchedualServiceHi {

    @RequestMapping(value = "/haveatry",method = RequestMethod.GET)
    String sayHiFromClientOne(@RequestParam(value = "name") String name);

}

Feign - Hystrix

@FeignClient(fallback=…)

package com.mumu.springcloud_feign.service;

import com.mumu.springcloud_feign.service.SchedualServiceHi;
import org.springframework.stereotype.Component;

@Component
public class SchedualServiceHiHystric implements SchedualServiceHi {

    @Override
    public String sayHiFromClientOne(String name) {
        return "Fallback | sorry! 网络异常，服务暂时无法访问。 请求的name为:"+name;
    }
}

@FeignClient(fallbackFactory=…)

支持打印出异常日志（推荐）

package com.mumu.springcloud_feign.service;

import org.springframework.cloud.openfeign.FallbackFactory;
import org.springframework.stereotype.Component;

@Component
public class SchedualServiceHiHystricFacotry implements FallbackFactory<SchedualServiceHi> {

    @Override
    public SchedualServiceHi create(Throwable cause) {
        return new SchedualServiceHi() {
            @Override
            public String sayHiFromClientOne(String name) {
                System.out.println("异常日志error:"+cause);
                return "FallbackFactory | sorry! 网络异常，服务暂时无法访问。 请求的name为:"+name;
            }
        };
    }
}

问题记录

错误日志: Could not find artifact org.springframework.cloud:spring-cloud-starter-netflix-hystrix:pom:unknown in central (https://repo.maven.apache.org/maven2)

参考博客解决方式: Could not find artifact org.springframework.cloud:spring-cloud-starter-netflix-eureka-client:pom

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
    <version>2.2.1.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-hystrix-dashboard</artifactId>
    <version>2.2.1.RELEASE</version>
</dependency>