unable to bind list of object properties from application.yml in spring

Question

I want to bind a list of object properties to a field in spring bean, but spring does not bind it. What am I missing? My env is SpringBoot v2.7.1 + Java 8.

application.yml

 application: mappings: - oldname: 'old name 1' newname: 'new name 1' - oldname: 'old name 2' newname: 'new name 2'

MappingProperties.java

 @ConfigurationProperties(prefix = "application") public class MappingProperties { private List<Mapping> mappings; public List<Mapping> getServers() { return mappings; } public void setServers(List<Mapping> mappings) { this.mappings = mappings; } public class Mapping { private String oldname; private String newname; public String getOldname() { return oldname; } public void setOldname(String oldname) { this.oldname = oldname; } public String getNewname() { return newname; } public void setNewname(String newname) { this.newname = newname; } } }

DemoApplication.java

 @EnableConfigurationProperties(MappingProperties.class) @SpringBootApplication public class DemoApplication implements CommandLineRunner { @Autowired private MappingProperties mappingProperties; public static void main(String[] args) { SpringApplication.run(DemoApplication.class, args); } @Override public void run(String... args) throws Exception { System.out.println(mappingProperties); } }

Answer 1

Looks like you are missing @ConfigurationPropertiesScan https://www.baeldung.com/configuration-properties-in-spring-boot

UPD: an implementation example was found here: https://www.baeldung.com/spring-boot-yaml-list