删除PropertySourcesPlaceHolderConfigurer bean自动装配不起作用

Question

What is the purpose of adding "PropertySourcesPlaceholderConfigurer" as a bean in spring? . As far as I researched it says when you name your property file as application.properties, spring will automatically take the file when it is in src/main/resources Folder. Having so, when I remove the Bean Declaration for PropertySourcesPlaceholderConfigurer, it says couldn't autowire the property.

What am I missing, Why isn't it working without PropertySourcesPlaceholderConfigurer

Sample 1:

@Configuration
@PropertySource(value = { "application.properties" }, ignoreResourceNotFound = true)
@ComponentScan(basePackages = { Some Package })
public class ApplicationConfig {

    ApplicationConfig() {

    }

    @Bean
    public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
        return new PropertySourcesPlaceholderConfigurer();
    }

}

Sample 1 works fine, When I remove @PropertySources and @PropertySourcesPlaceholderConfigurer bean since spring will pick up application.properties automatically, it doesn't work.

Answer 1

it says when you name your property file as application.properties, spring will automatically take the file when it is in src/main/resources Folder

As I know - this is correct only for Spring Boot. For spring core you should define you prps in contxet. There are several ways. In xml

< context:property-placeholder location="classpath:application.properties" />

or using Java annotation

@Configuration
@PropertySource("classpath:application.properties")

It's not necessary to define PropertySourcesPlaceholderConfigurer since Spring 4.3RC2