我想，我会这样做的。（根据后来的评论编辑）
配置部件类：

@Data
@NoArgsConstructor
public class ComponentConfigPart {
    private String ex1;
    private String ex2;
    private String ex3;
}

Bean的基类

@Data
public abstract class ComponentConfig {
    private List<ComponentConfigPart> parts = new ArrayList<>();

    @PostConstruct
    public void init() {
        System.out.println("Created instance of " + this.getClass().getSimpleName());
        System.out.println("Created " + this);
    }
}

ComponentA类别

@Component
@ConfigurationProperties(prefix = "application.components.a")
@ConditionalOnProperty(prefix = "application", name = "use", havingValue = "componentA")
@ToString(callSuper = true)
public class ComponentAConfig extends ComponentConfig {
    
}

ComponentB类别：

@Component
@ConfigurationProperties(prefix = "application.components.b")
@ConditionalOnProperty(prefix = "application", name = "use", havingValue = "componentB")
@ToString(callSuper = true)
public class ComponentBConfig extends ComponentConfig {

}

以及MainConfig，它希望获得“选定”组件：

@Configuration
public class MainConfig {

    @Autowired
    private ComponentConfig config;

    @PostConstruct
    public void init() {
        System.out.println("MainConfig has autowired class of " + config.getClass().getSimpleName());
    }
}

现在，属性如下所示：

application:
  components:
    a:
      parts:
        - ex1: a
          ex2: aa
          ex3: aaa
        - ex1: a2
          ex2: aa2
          ex3: aaa2
    b:
      parts:
        - ex1: b
          ex2: bb
          ex3: bbb
        - ex1: b2
          ex2: bb2
          ex3: bbb2
  use: componentA

并在控制台日志中显示结果：

Created instance of ComponentAConfig
Created ComponentAConfig(super=ComponentConfig(parts=[ComponentConfigPart(ex1=a, ex2=aa, ex3=aaa), ComponentConfigPart(ex1=a2, ex2=aa2, ex3=aaa2)]))
MainConfig has autowired class of ComponentAConfig

类似地，如果属性如下所示：

application:
  components:
    a:
      parts:
        - ex1: a
          ex2: aa
          ex3: aaa
        - ex1: a2
          ex2: aa2
          ex3: aaa2
    b:
      parts:
        - ex1: b
          ex2: bb
          ex3: bbb
        - ex1: b2
          ex2: bb2
          ex3: bbb2
  use: componentB

其结果是：

Created instance of ComponentBConfig
Created ComponentBConfig(super=ComponentConfig(parts=[ComponentConfigPart(ex1=b, ex2=bb, ex3=bbb), ComponentConfigPart(ex1=b2, ex2=bb2, ex3=bbb2)]))
MainConfig has autowired class of ComponentBConfig

这就是我所寻找的行为，但每个组件都应该是这样的列表：

application:
  components:
    componentA:
        - ex1
          ex2
          ex3
        - ex1
          ex2
          ex3
    componentB:
        - ex1
          ex2
          ex3
        - ex1
          ex2
          ex3
    componentC:
        - ex1
          ex2
          ex3
        - ex1
          ex2
          ex3
use: componentA

这就是为什么我有MainConfig类与每个列表。