Reading a List from properties file and load with spring annotation @Value

Question

I want to have a list of values in a .properties file, ie:

my.list.of.strings=ABC,CDE,EFG

And to load it in my class directly, ie:

Answer 1

If you are using latest Spring framework version(Spring 3.1+ I believe), you don't need to those string split stuff in SpringEL,

Simply add PropertySourcesPlaceholderConfigurer and DefaultConversionService in your Spring's Configuration class ( the one with annotated with Configuration ) e.g,

@Configuration
public class AppConfiguration {

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

    @Bean public ConversionService conversionService() {
        return new DefaultConversionService();
    }
}

and in your class

@Value("${list}")
private List list;

and in the properties file

list=A,B,C,D,E

Without DefaultConversionService, you can only take comma separated String into String array when you inject the value into your field, but DefaultConversionService does a few convenient magic for you and will add those into Collection, Array, etc. ( check the implementation if you'd like to know more about it )

With these two, it even handles all the redundant whitespaces including newline, so you don't need to add additional logics to trim them.