@ConfigurationProperties:绑定类中的默认值 [英] @ConfigurationProperties: Default value in bound class

问题描述

我有一个配置类 FooConfig，其中我有一个绑定类Foo".

I have a config class FooConfig, in which i have a bound class 'Foo'.

@Configuration
@ConfigurationProperties("foo")
public class FooConfig {

  @Value("${foo.default.iterations}")
  private Integer iterations;

  private Foo foo;

  // getter / setter

}

在我的类 Foo 中，当未在属性文件中明确设置时，我希望迭代变量集具有现有的默认配置值.

In my class Foo I want the iterations-variable set with an existing default configuration-value, when not explicitly set in the properties-file.

public class Foo {

  private String name;

  @Value("${foo.default.iterations}")
  private Integer iterations;

  // getter / setter

}

我的属性文件

foo.default.iterations=999

# if this is set this config is bound (wins) in FooConfig-class as expected
# foo.iterations=111

foo.foo.name=foo

在 FooConfig 中设置默认值有效，但在我绑定的类 Foo 中无效.

Setting a default value in FooConfig works, but not in my bound class Foo.

我在这里遗漏了什么?

推荐答案

你不应该将 @Value 和 @ConfigurationProperties 混合在同一个类中.如果您想在 @ConfigurationProperties 注释的类中有默认值，您可以使用默认值配置字段:

You shouldn't mix @Value and @ConfigurationProperties in the same class. If you want to have default values in a @ConfigurationProperties-annotated class, you can configure the fields with a default value:

@ConfigurationProperties("foo")
public class FooConfig {

    private Integer iterations = 999;

    // getter / setter

}

此更改带来了额外的好处，即在 spring-boot-configuration-processor 生成的元数据中包含默认值.当您编辑 application.properties 和 application.yaml 文件时，IDE 会使用元数据提供自动完成功能.

This change brings with it the added benefit of including the default value in the metadata that's generated by spring-boot-configuration-processor. The metadata is used by your IDE to provide auto-completion when you're editing application.properties and application.yaml files.

最后，与您的问题没有直接关系的是，@ConfigurationProperties 注释的类不应使用 @Configuration 进行注释.@Configuration 注释类用于通过 @Bean 方法配置 bean.您的 FooConfig 类应该使用 @Component 进行注释，或者您应该在 @Configuration<上使用 @EnableConfigurationProperties(FooConfig.class)/code> 想要使用 FooConfig 的类.

Lastly, and not directly related to your problem, a @ConfigurationProperties-annotated class should not be annotated with @Configuration. An @Configuration-annotated class is used to configure beans via @Bean methods. Your FooConfig class should either be annotated with @Component or you should use @EnableConfigurationProperties(FooConfig.class) on the @Configuration class that wants to use FooConfig.

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