SpringBoot YML 配置List

異常：
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name ‘companyNewsService’: Unsatisfied dependency expressed through field ‘capricornSftpConfig’; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‘capricornSftpConfig’: Could not bind properties to CapricornSftpConfig (prefix=capricorn.sftp, ignoreInvalidFields=false, ignoreUnknownFields=true, ignoreNestedProperties=false); nested exception is org.springframework.beans.InvalidPropertyException: Invalid property ‘types[1]’ of bean class [com.hoau.capricorn.util.sftp.CapricornSftpConfig]: Illegal attempt to get property ‘types’ threw exception; nested exception is org.springframework.beans.NullValueInNestedPathException: Invalid property ‘types[1]’ of bean class [com.hoau.capricorn.util.sftp.CapricornSftpConfig]: Cannot access indexed value of property referenced in indexed property path ‘types[1]’: returned null
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:588)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:366)
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$1.getObject(AbstractBeanFactory.java:306) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208) at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585)
… 19 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‘capricornSftpConfig’: Could not bind properties to CapricornSftpConfig (prefix=capricorn.sftp, ignoreInvalidFields=false, ignoreUnknownFields=true, ignoreNestedProperties=false); nested exception is org.springframework.beans.InvalidPropertyException: Invalid property ‘types[1]’ of bean class [com.hoau.capricorn.util.sftp.CapricornSftpConfig]: Illegal attempt to get property ‘types’ threw exception; nested exception is org.springframework.beans.NullValueInNestedPathException: Invalid property ‘types[1]’ of bean class [com.hoau.capricorn.util.sftp.CapricornSftpConfig]: Cannot access indexed value of property referenced in indexed property path ‘types[1]’: returned null
at org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor.postProcessBeforeInitialization(ConfigurationPropertiesBindingPostProcessor.java:334)
at org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor.postProcessBeforeInitialization(ConfigurationPropertiesBindingPostProcessor.java:291)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:409)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1620)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208) at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585)
… 32 common frames omitted
Caused by: org.springframework.beans.InvalidPropertyException: Invalid property ‘types[1]’ of bean class [com.hoau.capricorn.util.sftp.CapricornSftpConfig]: Illegal attempt to get property ‘types’ threw exception; nested exception is org.springframework.beans.NullValueInNestedPathException: Invalid property ‘types[1]’ of bean class [com.hoau.capricorn.util.sftp.CapricornSftpConfig]: Cannot access indexed value of property referenced in indexed property path ‘types[1]’: returned null
at org.springframework.beans.AbstractNestablePropertyAccessor.getPropertyValue(AbstractNestablePropertyAccessor.java:722)
at org.springframework.beans.AbstractNestablePropertyAccessor.getNestedPropertyAccessor(AbstractNestablePropertyAccessor.java:850)
at org.springframework.beans.AbstractNestablePropertyAccessor.getPropertyAccessorForPropertyPath(AbstractNestablePropertyAccessor.java:827)
at org.springframework.beans.AbstractNestablePropertyAccessor.setPropertyValue(AbstractNestablePropertyAccessor.java:270)
at org.springframework.boot.bind.RelaxedDataBinder$RelaxedBeanWrapper.setPropertyValue(RelaxedDataBinder.java:699)
at org.springframework.beans.AbstractPropertyAccessor.setPropertyValues(AbstractPropertyAccessor.java:95)
at org.springframework.validation.DataBinder.applyPropertyValues(DataBinder.java:859)
at org.springframework.validation.DataBinder.doBind(DataBinder.java:755)
at org.springframework.boot.bind.RelaxedDataBinder.doBind(RelaxedDataBinder.java:128)
at org.springframework.validation.DataBinder.bind(DataBinder.java:740)
at org.springframework.boot.bind.PropertiesConfigurationFactory.doBindPropertiesToTarget(PropertiesConfigurationFactory.java:272)
at org.springframework.boot.bind.PropertiesConfigurationFactory.bindPropertiesToTarget(PropertiesConfigurationFactory.java:240)
at org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor.postProcessBeforeInitialization(ConfigurationPropertiesBindingPostProcessor.java:329)
… 45 common frames omitted
Caused by: org.springframework.beans.NullValueInNestedPathException: Invalid property ‘types[1]’ of bean class [com.hoau.capricorn.util.sftp.CapricornSftpConfig]: Cannot access indexed value of property referenced in indexed property path ‘types[1]’: returned null
at org.springframework.beans.AbstractNestablePropertyAccessor.getPropertyValue(AbstractNestablePropertyAccessor.java:653)
… 57 common frames omitted

如果將1⃣️代碼寫在集合空判斷之下，那麼this.types就永遠都不會被賦值，而後面的yml配置解析用到getTypes時，就會報錯了

	/**
	* @ConfigurationProperties整個是使用反射實例化對象，然後一點一點的填充值
	* 初始化時types是一個空list，將這個空列表塞到配置類實例中之後，再逐步將yml配置文件
	* 中的值解析出來，填充到list中
	**/
    public void setTypes(List<ItemDto> types) {	//set方法只會執行一次
        this.types = types;	//1⃣️
        if (CollectionUtils.isEmpty(types)){
            return;	//代碼會從這裏返回
        }
        for (Integer i= 0; i< types.size(); i++){
            types.get(i).setCode(i.toString());
        }
    }
    
    public List<ItemDto> getTypes() {
        return types;
    }