英文:

Cannot bind Map to Object in Spring Configuration Properties from YAML file

问题

我在我的Spring Boot的application.yml文件中有以下配置：

```yaml
project:
 country-properties:
   france:
     capital: 巴黎
     population: 60  

并且我有一个属性类：CountryProperties：

@Getter
@AllArgsConstructor
@ConstructorBinding
@ConfigurationProperties(prefix="project.country-properties") 
public class CountryProperties {
      private Map<String, CountryData> countryProperties;

      @Getter
      @Setter
      public static class CountryData {
          private String capital; 
          private Integer population; 
      }   

然而我的CountryProperties总是为null，这是因为与CountryData对象的映射失败了。
对我写的有什么错误有什么想法吗？

<details>
<summary>英文:</summary>

I have the following configuration in my Spring boot&#39;s application.yml file:  

project:
country-properties:
france:
capital: paris
population: 60

And I have the the properties class : CountryProperties : 


```java
@Getter
@AllArgsConstructor
@ConstructorBinding
@ConfigurationProperties(prefix="project.country-properties") 
public class CountryProperties {
      private Map<String, CountryData> countryProperties;

      @Getter
      @Setter
      public static class CountryData {
          private String capital; 
          private Integer population; 
      }   

However my CountryProperties is always null, and it's because of a failed mapping with the CountryData object.
Any ideas what is wrong with what I wrote?

答案1

得分: 1

以下是翻译好的部分：

你有注解 @ConstructorBinding。这个注解告诉 Spring 查找你的类中具有与配置属性相对应的参数的构造函数，然后将绑定这些属性。

你缺少的部分是：

    this.countryProperties = countryProperties;
}```

更新：

再次检查您的代码后，看起来您没有正确地将配置映射到实例字段。请将 ```@ConfigurationProperties(prefix="project.country-properties")``` 更新为 ```@ConfigurationProperties(prefix="project")```。

还要将 ```@ConstructorBinding``` 替换为 ```@Configuration```。

<details>
<summary>英文:</summary>

You have the annotation ```@ConstructorBinding```. This annotation tells Spring to look for a constructor in your class that has parameters corresponding to your configuration properties, and then will bind the properties.

What you are missing is:

public CountryProperties(Map<String, CountryData> countryProperties) {
this.countryProperties = countryProperties;
}

Update:

After inspecting your code again, it looks like you aren't mapping the configuration correctly to the instance field. Please update your ```@ConfigurationProperties(prefix="project.country-properties")``` to ```@ConfigurationProperties(prefix="project")```.

Also replace the ```@ConstructorBinding``` with ```@Configuration```.

</details>