使用Spring Boot和application.yml注入映射

Question

@SpringBootApplication
@EnableConfigurationProperties
public class Application implements ApplicationRunner {
    public static void main(String[] args) {
        SpringApplication.run(Application .class, args);
    }
}

@Component
@ConfigurationProperties(prefix = "somePrefix")
public class AClass {
    private final AnotherClass anotherClass;
    private final Map<String, Double> aMap;

    @Autowired
    public AffinityChecks(AnotherClass anotherClass,
                          Map<String, Double> aMap) {
        this.anotherClass = anotherClass;
        this.aMap = aMap;
    }

    // Omissis

somePrefix:
  aMap:
    key1: 0.6
    key2: 0.2
    key3: 0.2

org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'java.util.Map<java.lang.String, java.lang.Double>' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {}

到底是怎么回事？

提前谢了。

Answer 1

Spring Boot不支持绑定到环境的元素的构造函数注入。当然，您可以用通常的方式注入实际的豆子。

您需要将每个要绑定的属性定义为常规Javabean属性（即使用getter/setter）。这个规则有一个例外：映射和非标量值（即嵌套内容）只需要一个getter。

具体地说，如果AnotherClass是bean，FooClass是一些具有嵌套属性的pojo。

@Component
@ConfigurationProperties(prefix = "somePrefix")
public class AClass {
    private final AnotherClass anotherClass;
    private final Map<String, Double> aMap = new HashMap<>();
    private final FooClass foo = new FooClass();

    public AClass(AnotherClass anotherClass) { ...}

    public Map<String, Double> getaMap() { ... }

    public FooClass getFoo() { ... }

}