我通过maven与mvn clean install
spring-boot:run在嵌入式tomcat服务器上运行spring-boot.但每次我运行它我都会收到此错误:
Caused by: java.lang.IllegalArgumentException: Could not resolve placeholder ‘language’ in string value “${language}”
at org.springframework.util.PropertyPlaceholderHelper.parseStringValue(PropertyPlaceholderHelper.java:174) ~[spring-core-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.util.PropertyPlaceholderHelper.replacePlaceholders(PropertyPlaceholderHelper.java:126) ~[spring-core-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.core.env.AbstractPropertyResolver.doResolvePlaceholders(AbstractPropertyResolver.java:236) ~[spring-core-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.core.env.AbstractPropertyResolver.resolveRequiredPlaceholders(AbstractPropertyResolver.java:210) ~[spring-core-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.context.support.PropertySourcesPlaceholderConfigurer$2.resolveStringValue(PropertySourcesPlaceholderConfigurer.java:172) ~[spring-context-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.resolveEmbeddedValue(AbstractBeanFactory.java:831) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1086) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:366) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
… 35 common frames omitted
该错误与这两行代码有关:
@Value("${language}")
private String language;
那个语言标志在我的application.properties中指定,如下所示:
application.properties
language=java
logging.level.org.springframework=TRACE
这是一个令人困惑的部分:当我在没有spring-boot:run命令的情况下运行构建时,它构建正确,我可以运行构建的jar而不会出现任何问题.只有当我尝试在嵌入式tomcat服务器上运行时,我才遇到这个问题.
我可以通过在我的代码中执行此操作来绕过这个:
@Value("${language:java}")
private String language;
但这对我来说没有意义,因为spring应该自动从application.properties文件中读取默认值.
编辑:正如人们所指出的那样,在嵌入式tomcat服务器上运行时根本不会读取application.properties.有什么方法可以强迫它读取文件或者它可能没有读取它的原因?部署到外部应用服务器而不是嵌入式应用服务器时,它可以正常工作.
在此先感谢您的帮助.
通过在< resources>下将这些行添加到pom来修复部分
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
<includes>
<include>**/*.properties</include>
</includes>
</resource>
我不完全理解的是需要这样做.
a)我可以在外部应用服务器上运行它,而无需添加此行,应用程序读取application.properties就好了.
b)我可以在eclipse中将应用程序作为独立的java应用程序运行(即,无需通过maven构建应用程序)并且它读取application.properties就好了
c)不是弹簧启动应该默认读取它吗? (如上面的两个案例所示?)
谢谢大家的帮助.希望这会有助于其他人.