背景：

       springboot 和 dubbo 在 pom.xml 中的版本是有对应关系的，如果配置的依赖不按照对应关系配置的话项目启动就会报错，报错的信息如下所示：

java.lang.IllegalStateException: Cannot load configuration class: com.alibaba.boot.dubbo.autoconfigure.DubboAutoConfiguration
	at org.springframework.context.annotation.ConfigurationClassPostProcessor.enhanceConfigurationClasses(ConfigurationClassPostProcessor.java:403) ~[spring-context-4.3.12.RELEASE.jar:4.3.12.RELEASE]
	at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanFactory(ConfigurationClassPostProcessor.java:249) ~[spring-context-4.3.12.RELEASE.jar:4.3.12.RELEASE]
	at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:283) ~[spring-context-4.3.12.RELEASE.jar:4.3.12.RELEASE]
	at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:127) ~[spring-context-4.3.12.RELEASE.jar:4.3.12.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:687) ~[spring-context-4.3.12.RELEASE.jar:4.3.12.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:525) ~[spring-context-4.3.12.RELEASE.jar:4.3.12.RELEASE]
	at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.5.8.RELEASE.jar:1.5.8.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693) [spring-boot-1.5.8.RELEASE.jar:1.5.8.RELEASE]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360) [spring-boot-1.5.8.RELEASE.jar:1.5.8.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) [spring-boot-1.5.8.RELEASE.jar:1.5.8.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1118) [spring-boot-1.5.8.RELEASE.jar:1.5.8.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1107) [spring-boot-1.5.8.RELEASE.jar:1.5.8.RELEASE]
	at com.ProviderApplication.main(ProviderApplication.java:13) [classes/:na]

对应关系：

       我在项目中使用的阿里巴巴的 dubbo-spring-boot-starter 版本是 0.2.0 ，maven 依赖如下所示：

<dependency>
    <groupId>com.alibaba.boot</groupId>
    <artifactId>dubbo-spring-boot-starter</artifactId>
    <version>0.2.0</version>
</dependency>

       则对应的使用 spring-boot-starter-parent 的版本号是 2.1.6.RELEASE ，这样配置依赖的话，项目启动是没有问题的。

可以在 https://mvnrepository.com/artifact/com.alibaba.boot/dubbo-spring-boot-starter 里面查看 dubbo 的所有版本信息。