Could not find class [org.springframework.cloud.client.loadbalancer.LoadBalancerProperties]

错误信息： Could not find class [org.springframework.cloud.client.loadbalancer.LoadBalancerProperties]

java.lang.IllegalArgumentException: Could not find class [org.springframework.cloud.client.loadbalancer.LoadBalancerProperties]
	at org.springframework.util.ClassUtils.resolveClassName(ClassUtils.java:327)
	at org.springframework.core.annotation.TypeMappedAnnotation.adapt(TypeMappedAnnotation.java:483)
	at org.springframework.core.annotation.TypeMappedAnnotation.getValue(TypeMappedAnnotation.java:403)
	at org.springframework.core.annotation.TypeMappedAnnotation.asMap(TypeMappedAnnotation.java:288)
	at org.springframework.core.annotation.AbstractMergedAnnotation.asAnnotationAttributes(AbstractMergedAnnotation.java:193)
	at org.springframework.core.type.AnnotatedTypeMetadata.getAnnotationAttributes(AnnotatedTypeMetadata.java:106)
	at org.springframework.context.annotation.AnnotationConfigUtils.attributesFor(AnnotationConfigUtils.java:285)
	at org.springframework.context.annotation.AnnotationBeanNameGenerator.determineBeanNameFromAnnotation(AnnotationBeanNameGenerator.java:100)
	at org.springframework.context.annotation.AnnotationBeanNameGenerator.generateBeanName(AnnotationBeanNameGenerator.java:79)
	at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.registerBeanDefinitionForImportedConfigurationClass(ConfigurationClassBeanDefinitionReader.java:160)
	at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForConfigurationClass(ConfigurationClassBeanDefinitionReader.java:141)
	at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitions(ConfigurationClassBeanDefinitionReader.java:120)
	at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:337)
	at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:242)
	at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:275)
	at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:95)
	at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:706)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:532)
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141)
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747)
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:315)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215)
	at io.renren.RenrenApplication.main(RenrenApplication.java:21)
Caused by: java.lang.ClassNotFoundException: org.springframework.cloud.client.loadbalancer.LoadBalancerProperties
	at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
	at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
	at java.base/java.lang.Class.forName0(Native Method)
	at java.base/java.lang.Class.forName(Class.java:398)
	at org.springframework.util.ClassUtils.forName(ClassUtils.java:277)
	at org.springframework.util.ClassUtils.resolveClassName(ClassUtils.java:317)
	... 24 common frames omitted

这个问题，我在网上看了很多的文章，说的是版本的问题，我们可以尝试去官方或者博客来查看Spring Cloud版本和Spring Cloud Alibaba和Spring Boot的对应版本信息，提升或者降版本来测试，查看这个问题是否存在.

版本：版本参照

我的问题是：在使用renren-fast开源项目整合Spring Cloud Alibaba nacos框架的时候，出的错误，
首先先把renren-fast这个项目的Spring-Boot依赖降级

	<parent>
		<groupId>org.springframework.bootgroupId>
		<artifactId>spring-boot-starter-parentartifactId>
		<version>2.2.1.RELEASEversion>
	parent>

在nacos中排除这个依赖，如果我们没有排除这个依赖则会报

No Feign Client for loadBalancing defined. Did you forget to include spring-cloud-starter-loadbalancer?

如果你出现了这个异常则可以看一下这篇文章

<dependency>
            <groupId>com.alibaba.cloudgroupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discoveryartifactId>
            <exclusions>
                <exclusion>
                    <groupId>com.netflix.ribbongroupId>
                    <artifactId>ribbonartifactId>
                exclusion>
            exclusions>
        dependency>

导入spring-cloud-starter-loadbalancer包(我的就是这个包的版本问题，我在尝试着降级后问题解决了)

<dependency>
            <groupId>org.springframework.cloudgroupId>
            <artifactId>spring-cloud-starter-loadbalancerartifactId>
            <version>2.2.0.RELEASEversion>
        dependency>

spring-cloud-alibaba-dependencies 依赖的版本

<properties>
<spring-cloud-alibaba.version>2.2.1.RELEASEspring-cloud-alibaba.version>
properties>
<dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>com.alibaba.cloudgroupId>
                <artifactId>spring-cloud-alibaba-dependenciesartifactId>
                <version>${spring-cloud-alibaba.version}version>
                <type>pomtype>
                <scope>importscope>
            dependency>
        dependencies>
    dependencyManagement>

问题就解决了