java.lang.IllegalStateException: No instances available for CLOUD-PROVIDER-SERVICE

报错信息：java.lang.IllegalStateException: No instances available for CLOUD-PROVIDER-SERVICE

问题背景 :
依次启动eureka集群（7001和7002）、支付服务8001（服务提供者）、支付服务8002（服务提供者）、订单服务89（服务消费者）之后，在http://eureka7001.com:7001/和http://eureka7002.com:7002/的服务注册中心可视化页面中可以看到CLOUD-PROVIDER-SERVICE支付服务集群（8001和8002）已经被注册到eureka服务注册中心了，但是访问http://localhost:89/consumer/payment/getForEntity/1接口时，控制台会报上述异常信息。

解决方法：
我们需要在订单模块的pom依赖中添加以下依赖：

<dependency>
   <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-netflix-ribbon</artifactId>
    <version>2.2.9.RELEASE</version>
</dependency>

然后重启订单模块，再次访问：http://localhost:89/consumer/payment/getForEntity/1

返回结果正常。

---

在这里贴出订单服务完整的pom.xml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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>cloud2020</artifactId>
        <groupId>com.atguigu.springcloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>cloud-consumer-order80</artifactId>

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

<!--        <dependency>-->
<!--            <groupId>org.springframework.boot</groupId>-->
<!--            <artifactId>spring-boot-devtools</artifactId>-->
<!--            <scope>runtime</scope>-->
<!--            <optional>true</optional>-->
<!--        </dependency>-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!--引入自己定义的api通用包，可以使用Payment支付Entity-->
        <dependency>
            <groupId>com.atguigu.springcloud</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>${project.version}</version>
        </dependency>
<!--        <dependency>-->
<!--            <groupId>org.springframework.cloud</groupId>-->
<!--            <artifactId>spring-cloud-netflix-eureka-client</artifactId>-->
<!--        </dependency>-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
            <version>3.0.1</version>
        </dependency>
        <dependency>
            <groupId>com.netflix.ribbon</groupId>
            <artifactId>ribbon-loadbalancer</artifactId>
            <version>2.3.0</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-netflix-ribbon</artifactId>
            <version>2.2.9.RELEASE</version>
        </dependency>
    </dependencies>
</project>