.properties 文件中的 PropertyPlaceholderConfigurer 和环境变量

2022-01-16 00:00:00 environment-variables spring java applicationcontext properties-file

我有一个带有 PropertyPlaceholderConfigurer 的 Spring application-context.xml，用于从 .properties 文件中获取属性值.主要和测试源文件夹具有单独的 .properties 文件.问题是我需要在 .properties 文件中使用环境变量.但是当我按照以下方式进行操作时:

I have a Spring application-context.xml with PropertyPlaceholderConfigurer to get properties' values from .properties file. Main and test source folders have separate .properties file. The issue is that I need to use environment variables in .properties file. But when I do it in the following way:

property.name=${env.SYSTEM_PROPERTY}

我收到以下错误:

org.springframework.beans.factory.BeanDefinitionStoreException: Invalid bean definition with name 'beanName' defined in class path resource [com/example/applicationContext.xml]: Could not resolve placeholder 'env.SYSTEM_PROPERTY'

而占位符配置器定义为

<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="location" value="classpath:com/example/application.properties"/>
</bean>

任何想法如何使 property.name 被解释为环境变量(而不是占位符)?

Any ideas how-to make property.name be interpreted as environment variable (and not as placeholder)?

最好的问候，德米特里.

Best regards, Dmitriy.

推荐答案

我可能会彻底改变解决方案:直接注入系统属性，而不是注入引用系统属性的属性

I'd probably change the solution completely: inject the system property directly, as opposed to injecting the property which refers to a system property

例如

@Value("#{ systemProperties['JAVA_MY_ENV'] }") 
private String myVar;

或

<property name ="myVar" value="#{systemProperties['JAVA_MY_ENV']}"/>

我使用这样的属性占位符配置器

I use a property placeholder configurer like this

<bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
  <property name="locations">
    <list>
        <value>classpath:someprops.properties</value>
    </list>
  </property>
  <property name="ignoreResourceNotFound" value="true" />
  <property name="searchSystemEnvironment" value="true" />
  <property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE" />

您还必须记住使用 

 -DJAVA_MY_ENV=xyz

这样，当您运行生产版本时，您可以传递一件事，而在运行测试时传递另一件事.

This way when you run the production version you can pass one thing and when you are running tests another.

我经常做的事情是这样的:

Also what I often what I do is something like this:

  <property name="locations">
    <list>
      <value>classpath:someprops.properties</value>
      <value>classpath:someprops-{environment}.properties</value>
    </list>
  </property>

其中环境是 prod/stage/test/int/ci/local(每个环境 1 个 - 您现在可能只有 2 或 3 个).您可以将环境变量传递给程序.无论其在本地 pc/tests 上的生产/运行是否在 someprops.properties 属性文件中，任何应该相同的属性.任何特定于环境/运行方式的文件都将放入更具体的文件中(您应该将其放入 someprops.properties 文件以及默认值，除非被覆盖机制)

where environment is prod/stage/test/int/ci/local (1 per environment - you may only have 2 or 3 for now). You can pass the environment variable to the program. Any properties which should be the same regardless of if its production/running on your local pc/tests would be in the someprops.properties property file. Any ones specific to the environment/way its being run as will go in the more specific file (you should put it in the someprops.properties file as well as a default unless overridden mechanism)

例如在类路径中:someprops.properties

E.g. in classpath:someprops.properties

url=www.mysite.com

在类路径中:someprops-local.properties

in classpath:someprops-local.properties

url=localhost

通过使用这个基本思想，您可以以干净的方式分离测试和程序的正常运行属性.

By using this basic idea you can separate tests and the program's normal running properties in a clean manner.

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