[英]Spring Boot with Kotlin - @Value annotation not working as expected
I'm developing a Spring boot application using Kotlin.我正在使用 Kotlin 开发 Spring 启动应用程序。 Since I need to connect to an external API (cloudinary) I decided to add to my app a configuration class in order to store (and hide from VCS) my sensible data like username, passwords or API keys.
由于我需要连接到外部 API(cloudinary),我决定向我的应用程序添加一个配置类,以便存储(并向 VCS 隐藏)我的敏感数据,如用户名、密码或 API 密钥。
So this is what i did:所以这就是我所做的:
I created a Config class:我创建了一个 Config 类:
package demons
import org.springframework.beans.factory.annotation.Value
import org.springframework.context.annotation.Configuration
import org.springframework.context.annotation.PropertySource
@Configuration
@PropertySource("classpath:application.properties")
class AppConfig {
@Value("\${test.prop}")
val testProperty: String? = null
}
Then I added a test.prop entry in my application.properties file然后我在 application.properties 文件中添加了一个 test.prop 条目
test.prop=TEST
However, in every test I run, after creating an instance of AppConfig, his testProperty attribute is null
instead of being the string TEST
.但是,在我运行的每个测试中,在创建 AppConfig 实例后,他的 testProperty 属性为
null
而不是字符串TEST
。
For instance this snippet:例如这个片段:
val config = AppConfig()
System.out.println(config.testProperty)
would print out:会打印出来:
null
I've also tried using a separate .properties file instead of the default one like myproperties.properties
and declaring the variable as lateinit var
.我还尝试使用单独的 .properties 文件而不是像
myproperties.properties
这样的默认文件,并将变量声明为lateinit var
。 In this last case the variable seems to never be initialized:在最后一种情况下,变量似乎从未被初始化:
kotlin.UninitializedPropertyAccessException: lateinit property testProperty has not been initialized
What am I missing?我错过了什么?
The issue is that you are creating the instance of AppConfig
yourself via the constructor:问题是您正在通过构造函数自己创建
AppConfig
的实例:
val config = AppConfig()
While this class might have Spring annotations, it is NOT spring managed if you create the instance yourself.虽然此类可能具有 Spring 注释,但如果您自己创建实例,则它不是由 spring 管理的。
I recommend you borrow from the link you mentioned in my other answer.我建议您从我在其他答案中提到的链接借用。 There are good examples of using SpringBoot to create a Spring application for you.
有使用 SpringBoot 为您创建 Spring 应用程序的好例子。 Below I created a 'merged' example of your test + an example from the link.
下面我创建了一个“合并”的测试示例+来自链接的示例。 There is no need to specify a properties file, as
application.properties
is used as a property source by default.无需指定属性文件,因为
application.properties
默认用作属性源。
@SpringBootApplication
class AppConfig {
@Value("\${test.prop}")
val testProperty: String? = null
}
fun main(args: Array<String>) {
val appContext = SpringApplication.run(AppConfig::class.java, *args)
val config = appContext.getBean(AppConfig::class.java)
System.out.println(config.testProperty)
}
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