java 使用 spring-boot 在库中设置默认属性
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Set default properties in a library with spring-boot
提问by Eric D
I have many different services using spring-boot. I'd like to set up some configuration that is common for each, but allow the services to have their own properties and override them if they want. Example properties include spring.show_banner, management url ones, etc.
我使用 spring-boot 有许多不同的服务。我想设置一些通用的配置，但允许服务拥有自己的属性并根据需要覆盖它们。示例属性包括 spring.show_banner、管理 url 等。
How can I do this? If I have the following:
我怎样才能做到这一点？如果我有以下几点：
- service-common with src/main/resources/application.yml with default properties
- service1 with src/main/resources/application.yml with its own properties
- 带有默认属性的 src/main/resources/application.yml 的 service-common
- service1 带有 src/main/resources/application.yml 和它自己的属性
I'd like them to be merged with the service1 version taking precedence. Instead, it seems that only the first one found on the classpath is used.
我希望它们与优先的 service1 版本合并。相反，似乎只使用了在类路径上找到的第一个。
(Alternatively, using @Configuration classes would be even better, but I'm not sure they can be used to define many of the properties)
（或者，使用 @Configuration 类会更好，但我不确定它们是否可用于定义许多属性）
回答by Andy Wilkinson
There are several options available to you, all based on the order in which property sources are considered.
If your common library is responsible for creating the SpringApplicationit can use setDefaultProperties. These values can be overridden by your services' application.properties.
如果您的公共库负责创建SpringApplication它可以使用setDefaultProperties. 这些值可以被您的服务覆盖application.properties。
Alternatively, your library could use @PropertySourceon one of its @Configurationclasses to configure, for example, library.propertiesas a source. Again, these properties could then be overriden in your services' application.properties.
或者，您的库可以使用@PropertySource它的一个@Configuration类来配置，例如，library.properties作为源。同样，这些属性可以在您的服务中被覆盖application.properties。
回答by Gabriel Ruiu
I am not sure what you mean by merging them.
我不确定合并它们是什么意思。
But I'm assuming that in the end, you are describing the situation where you have profile-specific configuration. Because, any properties that are specific to a certain service can be managed/injected using Spring profiles, which will always take precedence over default property files(see documentation).
但我假设最后，您正在描述具有特定于配置文件的配置的情况。因为，特定于某个服务的任何属性都可以使用 Spring 配置文件进行管理/注入，这将始终优先于默认属性文件（请参阅文档）。
For example, you can have the file application-service1.propertieswhich would automatically be used when you run your app with the property spring.profiles.active=service1, which can be specified in the command line and otherplaces. If you don't specify this property, Spring Boot will fallback to the default application.propertiesfile.
例如，您可以拥有application-service1.properties文件，当您使用spring.profiles.active=service1属性运行应用程序时，该文件将自动使用，该属性可以在命令行和其他地方指定。如果不指定此属性，Spring Boot 将回退到默认的application.properties文件。
And you can of course write the common properties in both files:
您当然可以在两个文件中编写公共属性：
application.properties
应用程序属性
service.url=http://localhost:8080/endpoint
service.user=admin
service.password=admin
application-service1.properties
application-service1.properties
service.url=http://api.service.com/endpoint
service.user=admin
service.password=aosdnoni3
Hope this helps.
希望这可以帮助。
Sorry for the bad formatting, I'm still unfamiliar with the editor.
抱歉格式不正确，我仍然不熟悉编辑器。
回答by Dennis Crissman II
public class MyApplicationListener implements ApplicationListener<ApplicationEvent> {
@Override
public void onApplicationEvent(ApplicationEvent event) {
if (event instanceof ApplicationEnvironmentPreparedEvent) {
ApplicationEnvironmentPreparedEvent envEvent = (ApplicationEnvironmentPreparedEvent) event;
ConfigurableEnvironment env = envEvent.getEnvironment();
Properties props = new Properties();
//set props as desired
env.getPropertySources()
.addFirst(new PropertiesPropertySource("customname", props));
}
}
Then in src/main/resources/META-INF/spring.factories, add line:
org.springframework.context.ApplicationListener=mypackage.MyApplicationListener
然后在 src/main/resources/META-INF/spring.factories 中，添加一行：
org.springframework.context.ApplicationListener=mypackage.MyApplicationListener
