nested exception is org.springframework.core.convert.ConverterNotFoundException

nested exception is org.springframework.core.convert.ConverterNotFoundException

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【问题现象】

最近遇到一个很神奇的问题，报错如下：

nested exception is org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type [java.util.HashMap<?, ?>] to type [java.lang.String]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:372)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1264)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:761)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543)

原因是个人在application.properties定义了一个变量 cpu.usage.upper.limit，没有注意到配置文件中已经有一个变量，名为 cpu.usage

cpu.usage=70
cpu.usage.upper.limit=90

程序在引用变量 cpu.usage 的时候，就报了上述错误。

@Value("${cpu.usage:}")
private String cpuUsage ;

【问题原因】

 程序会认为 cpu.usage.upper.limit 是 cpu.usage 的子项，导致解析错误。

【解决方案】

将其中一个变量名修改一下，保证二者没有包含关系即可。

比如：将变量 cpu.usage.upper.limit 改成 cpuUsage.upper.limit