解决：Did you forget to include spring-cloud-starter-loadbalancer?

问题：
1、Spring-cloud-openfeign 在 Hoxton.M2 RELEASED 版本之后不再使用 ribbon 组件
2、而是使用 spring-cloud-starter-loadbalancer 作为负载均衡组件，所以在不引入该组件的情况下会报错

Caused by: java.lang.IllegalStateException: No Feign Client for loadBalancing defined. Did you forget to include spring-cloud-starter-loadbalancer?

解决：

1、导入 spring-cloud-starter-loadbalancer 依赖即可

        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.cloud</groupId>
                    <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

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