震惊！【Eureka】发生Cannot execute request on any known server异常这样解决

<dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
            <version>3.0.1</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--eureka安全登录验证需要-->
        <!--<dependency>-->
            <!--<groupId>org.springframework.boot</groupId>-->
            <!--<artifactId>spring-boot-starter-security</artifactId>-->
        <!--</dependency>-->
</dependencies>
 
<dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Hoxton.SR6</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
</dependencyManagement>

eureka:
  client:
#    往eureka注册中心注册自己，默认为true
    register-with-eureka: false
#    单节点的EurekaServer，不需要同步其他的EurekaServer节点的数据，所以设置为false
    fetch-registry: false

server:
  port: 8087
  servlet:
    context-path: /eureka
 
eureka:
  instance:
    hostname: localhost
    appname: eurekaServer
  client:
#    自己的eureka中注册自己，默认为true
    register-with-eureka: false
#    单节点的EurekaServer，不需要同步其他的EurekaServer节点的数据，所以设置为false
    fetch-registry: false
    service-url:
#      defaultZone: http://127.0.0.1:${server.port}/eureka/eureka/
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/eureka/

      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/eureka/

defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

server:
  port: 8087
  servlet:
    context-path: /eureka
eureka:
  instance:
    hostname: localhost
    appname: eurekaServer
  client:
#    自己的eureka中注册自己，默认为true
    register-with-eureka: false
#    单节点的EurekaServer，不需要同步其他的EurekaServer节点的数据，所以设置为false
    fetch-registry: false
    service-url:
#      defaultZone: http://127.0.0.1:${server.port}/eureka/eureka/
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/eureka/
  server:
    #设为false，关闭自我保护，即Eureka server在云心光器件会去统计心跳失败比例在15分钟之内是否低于85%,如果低于85%，EurekaServer
    #会将这些事例保护起来，让这些事例不会过期，但是在保护器内如果刚哈这个服务提供者非正常下线了，此时服务消费者会拿到一个无效的服务
    #实例，此时调用会失败，对于这个问题需要服务消费者端有一些容错机制，如重试、断路器等；
    enable-self-preservation: true
    #扫描失效服务的间隔时间（单位是毫秒，摩恩是60*1000)，即60s
    eviction-interval-timer-in-ms: 10000

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

    <dependencies>
        <!--  添加springboot fegin依赖，product项目即可以作为生产者，又可以作为消费者-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
 
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
    </dependencies>

spring:
  application:
    name: mixer-server

eureka:
  instance:
    appname: mixer-server

spring:
  application:
    name: mixer-server
eureka:
  #与spring.application.name二选其一作为euraka-server服务标识，此处我使用的是前者
  #instance:
    #appname: user-server
  client:
    service-url:
      defaultZone: http://localhost:8087/eureka/eureka/

@SpringBootApplication
//@EnableEurekaClient 和 @EnableDiscoveryClient 都是让eureka发现该服务并注册到eureka上的注解
//相同点：都能让注册中心Eureka发现，并将该服务注册到注册中心上；
//不同点：@EnableEurekaClient只适用于Eureka作为注册中心，
//而@EnableDiscoveryClient可以是其他注册中心；
//@EnableDiscoveryClient
@EnableEurekaClient
//表示开启Fegin客户端a
@EnableFeignClients
public class MixerStationApplication {
 
    public static void main(String[] args) {
        SpringApplication.run(MixerStationApplication.class, args);
    }
 
}