目录
场景：
问题描述：
原因分析：
解决方案：
方案一：
方案二：
场景：
我在学着怎么将nacos的配置拉取下来，但是很不幸的是，读取不到nacos上的配置，只能读取到本地的properties。
问题描述：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'scopedTarget.smsCouponController': Injection of autowired dependencies failed; nested exception is java.lang.IllegalArgumentException: Could not resolve placeholder 'coupon.user.name' in value "${coupon.user.name}"at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:405) ~[spring-beans-5.3.23.jar:5.3.23]at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1431) ~[spring-beans-5.3.23.jar:5.3.23]at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:619) ~[spring-beans-5.3.23.jar:5.3.23]at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.23.jar:5.3.23]at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$1(AbstractBeanFactory.java:374) ~[spring-beans-5.3.23.jar:5.3.23]at org.springframework.cloud.context.scope.GenericScope$BeanLifecycleWrapper.getBean(GenericScope.java:376) ~[spring-cloud-context-3.1.5.jar:3.1.5]at org.springframework.cloud.context.scope.GenericScope.get(GenericScope.java:179) ~[spring-cloud-context-3.1.5.jar:3.1.5]at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:371) ~[spring-beans-5.3.23.jar:5.3.23]at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.23.jar:5.3.23]at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1154) ~[spring-context-5.3.23.jar:5.3.23]at org.springframework.cloud.context.scope.refresh.RefreshScope.eagerlyInitialize(RefreshScope.java:126) ~[spring-cloud-context-3.1.5.jar:3.1.5]at org.springframework.cloud.context.scope.refresh.RefreshScope.start(RefreshScope.java:118) ~[spring-cloud-context-3.1.5.jar:3.1.5]at org.springframework.cloud.context.scope.refresh.RefreshScope.onApplicationEvent(RefreshScope.java:113) ~[spring-cloud-context-3.1.5.jar:3.1.5]at org.springframework.cloud.context.scope.refresh.RefreshScope.onApplicationEvent(RefreshScope.java:68) ~[spring-cloud-context-3.1.5.jar:3.1.5]at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:176) ~[spring-context-5.3.23.jar:5.3.23]at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:169) ~[spring-context-5.3.23.jar:5.3.23]at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:143) ~[spring-context-5.3.23.jar:5.3.23]at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:421) ~[spring-context-5.3.23.jar:5.3.23]at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:378) ~[spring-context-5.3.23.jar:5.3.23]at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:938) ~[spring-context-5.3.23.jar:5.3.23]at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:586) ~[spring-context-5.3.23.jar:5.3.23]at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145) ~[spring-boot-2.6.13.jar:2.6.13]at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:745) [spring-boot-2.6.13.jar:2.6.13]at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:420) [spring-boot-2.6.13.jar:2.6.13]at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) [spring-boot-2.6.13.jar:2.6.13]at org.springframework.boot.SpringApplication.run(SpringApplication.java:1317) [spring-boot-2.6.13.jar:2.6.13]at org.springframework.boot.SpringApplication.run(SpringApplication.java:1306) [spring-boot-2.6.13.jar:2.6.13]at com.guli.GulimailCouponApplication.main(GulimailCouponApplication.java:14) [classes/:na]
Caused by: java.lang.IllegalArgumentException: Could not resolve placeholder 'coupon.user.name' in value "${coupon.user.name}"at org.springframework.util.PropertyPlaceholderHelper.parseStringValue(PropertyPlaceholderHelper.java:180) ~[spring-core-5.3.23.jar:5.3.23]at org.springframework.util.PropertyPlaceholderHelper.replacePlaceholders(PropertyPlaceholderHelper.java:126) ~[spring-core-5.3.23.jar:5.3.23]at org.springframework.core.env.AbstractPropertyResolver.doResolvePlaceholders(AbstractPropertyResolver.java:239) ~[spring-core-5.3.23.jar:5.3.23]at org.springframework.core.env.AbstractPropertyResolver.resolveRequiredPlaceholders(AbstractPropertyResolver.java:210) ~[spring-core-5.3.23.jar:5.3.23]at org.springframework.context.support.PropertySourcesPlaceholderConfigurer.lambda$processProperties$0(PropertySourcesPlaceholderConfigurer.java:191) ~[spring-context-5.3.23.jar:5.3.23]at org.springframework.beans.factory.support.AbstractBeanFactory.resolveEmbeddedValue(AbstractBeanFactory.java:936) ~[spring-beans-5.3.23.jar:5.3.23]at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1332) ~[spring-beans-5.3.23.jar:5.3.23]at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1311) ~[spring-beans-5.3.23.jar:5.3.23]at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.resolveFieldValue(AutowiredAnnotationBeanPostProcessor.java:656) ~[spring-beans-5.3.23.jar:5.3.23]at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:639) ~[spring-beans-5.3.23.jar:5.3.23]at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:119) ~[spring-beans-5.3.23.jar:5.3.23]at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:399) ~[spring-beans-5.3.23.jar:5.3.23]... 27 common frames omitted原因分析：
无法解析值“$｛coupon.user.name｝”中的占位符“coupon.user.name”，也就是找不到coupon.user.name，在nacos配置中心读取不到配置，启动类就一直报错。
解决方案：
方案一：
bootstrap是属于springcloud的，如果你的项目只是一个springboot项目的话，那么是只会去读取application.yml/application.properties文件的，所以要读取bootstrap需要有cloud相关的一些配置才能够去正常读取它。
如果springboot版本低于2.4.0版本，则需要在pom里添加依赖：
<dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-context</artifactId>
</dependency>
如果springboot版本高于2.4.0版本，则需要在pom里添加依赖：
<dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-bootstrap</artifactId>
</dependency>
方案二：
仔细检查一下是不是你的配置里面的
application:name中的name写错了。
还有nacos配置文件中的Data ID，Data ID的格式（注意不要忘记加后缀）：
${prefix}-${spring.profile.active}.${file-extension}
${prefix}:
默认为所属工程配置spring.application.name的值(这就是为什么平时我们直接用服务名就可以),也可以用spring.cloud.nacos.config.prefix来配置.
${spring.profile.active}:
spring.profile.active即为当前环境对应的profile.注意:当spring.profile.active为空的时候,对应的连接符 - 也将不存在,dataId的拼接格式变成prefix.{file-extension}
${file-extension}:
为配置内容的数据格式，可以通过配置项 spring.cloud.nacos.config.file-extension 来配置。目前只支持 properties 和 yaml 类型。
参考文章：nacos的dataId规则_nacos配置dataid_白帆瀚宇的博客-CSDN博客
