Java Spring Boot：从 YAML 文件加载 @Value
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Spring Boot: Load @Value from YAML file
提问by Thomas Schmidt
I need to load a property from a .ymlfile, which contains the path to a folder where the application can read files from.
我需要从.yml文件加载一个属性，该文件包含应用程序可以从中读取文件的文件夹的路径。
I'm using the following code to inject the property:
我正在使用以下代码注入属性：
@Value("${files.upload.baseDir}")
private String pathToFileFolder;
The .ymlfile for development is located under src/main/resources/config/application.yml, im running the application with the following command in production, to override the development settings:
在.yml发展文件位于下src/main/resources/config/application.yml，即时通讯运行在生产下列命令的应用程序，覆盖开发设置：
java -jar app.jar --spring.config.location=/path/to/application-production.yml
The Spring Boot documentation says:
Spring Boot 文档说：
SpringApplication will load properties from application.properties files in the following locations and add them to the Spring Environment:
A /config subdirectory of the current directory.
The current directory
A classpath /config package
The classpath root
SpringApplication 将从以下位置的 application.properties 文件加载属性并将它们添加到 Spring Environment：
当前目录的 /config 子目录。
当前目录
一个类路径 /config 包
类路径根
As well as:
也：
You can also use YAML ('.yml') files as an alternative to '.properties'.
您还可以使用 YAML ('.yml') 文件作为 '.properties' 的替代文件。
The .ymlfile contains:
该.yml文件包含：
{...}
files:
upload:
baseDir: /Users/Thomas/Code/IdeaProjects/project1/files
{...}
And my Applicationclass is annotated with:
我的Application班级注释为：
@SpringBootApplication
@EnableCaching
When I run the application, i get an exception:
当我运行应用程序时，出现异常：
Caused by: java.lang.IllegalArgumentException: Could not resolve placeholder 'files.upload.baseDir' in string value "${files.upload.baseDir}"
Do I have to use the YamlPropertySourceLoaderclass or add a special annotation to enable the support for .ymlin Spring Boot?
我是否必须使用YamlPropertySourceLoader该类或添加特殊注释才能.yml在 Spring Boot 中启用对 的支持？
Edit:
The .ymlfile contains some other properties, which get successfully loaded by Spring Boot like dataSource.XXXor hibernate.XXX.
编辑：该.yml文件包含一些其他属性，这些属性可以通过 Spring Boot 成功加载，例如dataSource.XXX或hibernate.XXX。
采纳答案by Thomas Schmidt
M. Deinum is right, the setup i've provided is working - the ymlfile was indented wrong, so the property couldn't be found.
M. Deinum 是对的，我提供的设置正在运行 -yml文件缩进错误，因此无法找到该属性。
回答by SatyaRajC
For me a duplicate key in the property file caused this...
对我来说，属性文件中的重复键导致了这个......
I used same key unknowingly in large yml file.
我在大 yml 文件中不知不觉地使用了相同的密钥。
key:
key1: value
key2: value
key:
key3: value
回答by Nick Kras Borges
For example: application.yml
例如：application.yml
key:
name: description here
Your Class:
你的班：
@Value("${key.name}")
private String abc;
回答by Kjeld
I found the above wasn't working for me, because I tried to access the variable in a constructor. But at construction, the value is not injected yet. Eventually I got it to work using this workaround: https://mrhaki.blogspot.com/2015/04/spring-sweets-using-value-for.html
我发现上面的方法对我不起作用，因为我试图在构造函数中访问变量。但是在构建时，尚未注入该值。最终我使用这个解决方法让它工作：https: //mrhaki.blogspot.com/2015/04/spring-sweets-using-value-for.html
Maybe this is helpful to others.
也许这对其他人有帮助。
