将 Java.Util.Set 加载到 Spring ConfigurationProperties

Question

Following Spring @ConfigurationProperties Class

@Component
@ConfigurationProperties(prefix = "prefix")
@EnableConfigurationProperties
public class config {
    private Set<String> mySet = new HashSet<>();
}

Following Yaml file

prefix:
  mySet: !!set {'element1',  'element2'}

Using SnakeYaml version 1.16

Results in the follow error:

Caused by: org.springframework.beans.InvalidPropertyException: Invalid property 'messageDelivery[0]' of bean class [location.Config]: Property referenced in indexed property path 'mySet[0]' is neither an array nor a List nor a Map; returned value was [element1]

Appears the error is occurring during serialization

Update

I tried with this yaml structure

prefix:
    mySet:
        element1
        element2

This resulted in a Set with only one value which is "element1 element2" it concatenated both together need to find out what will allow me to separate the the elements from each other

Answer 1

The Structure that I finally got working needed a comma added

prefix:
    mySet:
        element1,
        element2

Answer 2

Please try with:

prefix:
    ? element1
    ? element2

This should work in order to represent a set in yaml file. You can see the details here: https://learnxinyminutes.com/docs/yaml/

Answer 3

I see 2 problems in code you shared.

1. mySet is private, I'm wondering how Spring can load data into it
2. the YAML format is wrong, should be

prefix:
   mySet:
     - element1
     - element2