Spring Boot2.0 @ConfigurationProperties使用详解

<parent>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-parent</artifactId>
  <version>2.0.4.RELEASE</version>
  <relativePath/> <!-- lookup parent from repository -->
 </parent>

  <dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-web</artifactId>
  </dependency>
  <!--<dependency>-->
   <!--<groupId>org.hibernate.validator</groupId>-->
   <!--<artifactId>hibernate-validator</artifactId>-->
   <!--<version>6.0.11.Final</version>-->
   <!--<scope>compile</scope>-->
  <!--</dependency>-->
  <dependency>
   <groupId>org.projectlombok</groupId>
   <artifactId>lombok</artifactId>
  </dependency>
  <dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-configuration-processor</artifactId>
   <optional>true</optional>
  </dependency>

@Getter
@Setter
public class DocumentServerProperties {

  private String remoteAddress;
  private boolean preferIpAddress;
  private int maxConnections=0;
  private int port;
  private AuthInfo authInfo;
  private List<String> whitelist;
  private Map<String,String> converter;
  private List<Person> defaultShareUsers;

  @Getter
  @Setter
  public static class AuthInfo {

    private String username;
    private String password;
  }
}

@ConfigurationProperties(prefix = "doc")
@Component
public class DocumentServerProperties {
  //代码...
}

@ConfigurationProperties(prefix = "doc")
public class DocumentServerProperties {
  //代码...
}

@EnableConfigurationProperties
@Configuration
public class SomeConfiguration {
  private DocumentServerProperties documentServerProperties
    
  public SomeConfiguration(DocumentServerProperties documentServerProperties) {
    this.documentServerProperties = documentServerProperties;
  }

}

@Configuration
public class SomeConfiguration {
  
  @Bean
  public DocumentServerProperties documentServerProperties(){
    return new DocumentServerProperties();
  }
  
  @ConfigurationProperties("demo.third")
  @Bean
  public ThirdComponent thirdComponent(){
    return new ThirdComponent();
  }

}

doc.remote-address=127.0.0.1
doc.port=8080
doc.max-connections=30
doc.prefer-ip-address=true
#doc.whitelist=192.168.0.1,192.168.0.2
# 这种等同于下面的doc.whitelist[0] doc.whitelist[1]
doc.whitelist[0]=192.168.0.1
doc.whitelist[1]=192.168.0.2
doc.default-share-users[0].name=jack
doc.default-share-users[0].age=18
doc.converter.a=xxConverter
doc.converter.b=xxConverter
doc.auth-info.username=user
doc.auth-info.password=password

doc:
 remote-address: 127.0.0.1
 port: 8080
 max-connections: 30
 prefer-ip-address: true
 whitelist: 
  - 192.168.0.1
  - 192.168.0.2
 default-share-users: 
  - name: jack
   age: 18
 converter: 
  a: aConverter
  b: bConverter
 auth-info:
  username: user
  password: password

@ConfigurationProperties(prefix = "doc")
@Validated
public class DocumentServerProperties {
  @NotNull // 判断不为空的情况
  private String remoteAddress;
  
  //限制端口只能是80-65536之间
  @Min(80)
  @Max(65536)
  private int port;
  //其他代码
}

public class UserLoginValidator implements Validator {

  private static final int MINIMUM_PASSWORD_LENGTH = 6;

  public boolean supports(Class clazz) {
    return UserLogin.class.isAssignableFrom(clazz);
  }

  public void validate(Object target, Errors errors) {
    ValidationUtils.rejectIfEmptyOrWhitespace(errors, "userName", "field.required");
    ValidationUtils.rejectIfEmptyOrWhitespace(errors, "password", "field.required");
    UserLogin login = (UserLogin) target;
    if (login.getPassword() != null
       && login.getPassword().trim().length() < MINIMUM_PASSWORD_LENGTH) {
     errors.rejectValue("password", "field.min.length",
        new Object[]{Integer.valueOf(MINIMUM_PASSWORD_LENGTH)},
        "The password must be at least [" + MINIMUM_PASSWORD_LENGTH + "] characters in );
    }
  }
}

@ConfigurationProperties(prefix = "doc")
public class DocumentServerProperties implements Validator{
  @NotNull
  private String remoteAddress;
  private boolean preferIpAddress;
    //其他属性 
  
  @Override
  public boolean supports(Class<?> clazz) {
    return true;
  }

  @Override
  public void validate(Object target, Errors errors) {
    //判断逻辑其实可以参照上面的代码片段
  }
}

private List<Validator> getValidators(Bindable<?> target) {
  List<Validator> validators = new ArrayList<>(3);
  if (this.configurationPropertiesValidator != null) {
    validators.add(this.configurationPropertiesValidator);
  }
  if (this.jsr303Present && target.getAnnotation(Validated.class) != null) {
      validators.add(getJsr303Validator());
  }
  if (target.getValue() != null && target.getValue().get() instanceof Validator) {
    validators.add((Validator) target.getValue().get());
  }
  return validators;
}