1.在pom文件添加相关依赖

<dependencies>
    <!-- web -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <!-- common -->
    <dependency>
        <groupId>cn.kgc</groupId>
        <artifactId>hello-sc-2109-common</artifactId>
        <version>1.0-SNAPSHOT</version>
    </dependency>
    <!-- eureka 客户端依赖 -->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    </dependency>
    <!-- actuator监控信息完善 -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>
    <!-- ribbon -->
   <!-- <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
    </dependency>-->
    <!-- openfeign,已经内置啦ribbon -->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-openfeign</artifactId>
    </dependency>
    <!-- hystrix依赖 -->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
    </dependency>
</dependencies>

2.yml里面添加相关配置 default的用户名跟密码是eureka里面的yml相关配置提供的

server:
  port: 8888

spring:
  application:
    name: hello-consumer
  jackson:
    date-format: yyyy-MM-dd
    time-zone: GMT+8

logging:
  level:
    cn.kgc: debug

eureka:
  client:
    service-url:
      defaultZone: http://admin:1234@localhost:7001/eureka/,http://admin:1234@localhost:7002/eureka/
    register-with-eureka: true
    fetch-registry: true
  instance:
    instance-id: ${spring.application.name}-${server.port}
    prefer-ip-address: true

# 指定负载均衡策略
HELLO-PROVIDER:
  ribbon:
    NFLoadBalancerRuleCl assName: com.netflix.loadbalancer.RandomRule
feign:
  hystrix:
    enabled: true #启用断路器

3.启动类 添加注解

@SpringBootApplication
@EnableEurekaClient//注册到EurekaServer
@EnableFeignClients//@EnableFeignClients注解告诉框架扫描所有使用注解@FeignClient定义的feign客户端，并把feign客户端注册到IOC容器中。
@EnableHystrix //让断路器可用

4.service.feign. 添加crud接口

@FeignClient(value = "HELLO-PROVIDER",fallback = EmpFeignServiceHystrix.class)//微服务名称
public interface EmpServiceFeign {


    @GetMapping("/emp/list")
    public Result<List<Emp>> getEmpList();

    @GetMapping("/emp/{id}")
    public Result<Emp> getEmpById(@PathVariable("id") Integer id);

    @PostMapping("/emp")
    public Result<Emp> addEmp(@RequestBody Emp emp);

    @PutMapping("/emp")
    public Result<Emp> updateEmp(@RequestBody Emp emp);

    @DeleteMapping("/emp/{id}")
    public Result<Object> deleteEmpById(@PathVariable("id") Integer id);
}

5.service.hystrx. 实现curd接口

//容错处理
@Component
public class EmpFeignServiceHystrix implements EmpServiceFeign {

    @Override
    public Result<List<Emp>> getEmpList() {
        return Result.fail(20005,"员工列表接口繁忙");
    }

}

6.配置类common.config

@Configuration
public class WebConfig {
    @Bean
    @LoadBalanced//开启负载均衡的功能
    //@LoadBalanced注解，我们在使用这个注解后，就能在调用其他微服务的时候，通过服务实例名称就能进行调用其他的微服务，而不是直接把要调用的微服务的ip和端口号写死在代码当中。
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }
}