本篇文章主要介绍SringBoot中的@ConfigurationProperties注解，该注解是用来获取yml或者properties配置文件的配置信息，下面根据一些配置信息给出案例代码进行讲解。

@ConfigurationProperties 中属性介绍

案例代码介绍

下面在yml配置文件中配置：

user:
  name: "张三"
  age: 18
  hobbies: 
    - "看书"
    - "写代码"

代码实现：

@Component
@ConfigurationProperties(prefix = "user")
public class UserInfo {
    private String name;
    private int age;
    private List<String> hobbies;
}

这样，就能从配置文件中读取到配置的信息。

ignoreInvalidFields 属性用法

如果，我把ignoreInvalidFields属性值设置为false（ignoreInvalidFields属性值默认值就是fasle），然后把yml配置文件中的age修改成字符串类型，这样配置文件中的类型和Class中的类型不一致就会出现错误，以下是代码案例

user:
  name: "张三"
  age: 18
  hobbies: 
    - "看书"
    - "写代码"

代码实现：

@Component
@ConfigurationProperties(prefix = "user", ignoreInvalidFields = false)
public class UserInfo {
    private String name;
    private int age;
    private List<String> hobbies;
}

错误如下：

***************************
APPLICATION FAILED TO START
***************************

Description:

Failed to bind properties under 'user.age' to int:

    Property: user.age
    Value: 18岁
    Origin: class path resource [application.yml] - 10:8
    Reason: failed to convert java.lang.String to int (caused by java.lang.NumberFormatException: For input string: "18岁")

Action:

Update your application's configuration

ignoreUnknownFields 属性用法

这里，我把ignoreUnknownFields属性值设置为false（ignoreUnknownFields属性值默认值是true），然后把UserInfo文件中的hobbies变量删除，这样配置文件中的类型和Class中的属性就会不一致，接下来就会出现错误，以下是代码案例

user:
  name: "张三"
  age: 18
  hobbies: 
    - "看书"
    - "写代码"

代码实现：

@Component
@ConfigurationProperties(prefix = "user", ignoreUnknownFields = false)
public class UserInfo {
    private String name;
    private int age;
}

错误如下：

***************************
APPLICATION FAILED TO START
***************************

Description:

Binding to target [Bindable@31e2232f type = com.demo.UserInfo, value = 'provided', annotations = array<Annotation>[@org.springframework.boot.context.properties.ConfigurationProperties(ignoreInvalidFields=false, ignoreUnknownFields=false, prefix=user, value=user)]] failed:

    Property: user.hobbies[0]
    Value: 看书
    Origin: class path resource [application.yml] - 12:7
    Reason: The elements [user.hobbies[0],user.hobbies[1]] were left unbound.
    Property: user.hobbies[1]
    Value: 写代码
    Origin: class path resource [application.yml] - 13:7
    Reason: The elements [user.hobbies[0],user.hobbies[1]] were left unbound.

Action:

Update your application's configuration