Spring Boot：使用@ConfigurationProperties从yaml读取，但不使用@Data

Question

我正在尝试从application.yml.中检索值下面的最后一行显示kafkaConfig为null，无法读取。如何正确设置Kafka配置和代码以从json文件中读取？我们使用@Data而不是getters/setters。

KafkaConfig.java

@Configuration
@ConfigurationProperties("kafka")
@Data
public class KafkaConfig {
    private String topic;
    private String event;
}

应用yml公司

kafka:
  topic: "testTopic"
  event: "testEvent"

KafkaProducerBeans.java

@Component
public class KafkaProducerBeans {

    @Autowired
    private KafkaConfig kafkaConfig;

    public KafkaProducerBeans(KafkaConfig kafkaConfig) {
        this.kafkaConfig = kafkaConfig;
    }

    @Bean(name = "kafkaTestClient")
    public String getData() {
        return kafkaConfig.getTopic();  // final line is creating null for kafka Config
    }

资源：https://codingnconcepts.com/spring-boot/spring-configuration-properties-using-yml/

Answer 1

@组件扫描（basePackages=“PATH”）

PATH：您希望它查找的包路径

@ComponentScan(basePackages ="PATH" )
@Configuration
@Import(value = {
    KafkaProducerBeans.class
})
public class AppConfig{

}

Answer 2

在类KafkaConfig上添加一个注释@EnableConfigurationProperties

KafkaConfig.java

@Configuration
@EnableConfigurationProperties    // new added annotation
@ConfigurationProperties("kafka")
@Data
public class KafkaConfig {
    private String topic;
    private String event;
}

Answer 3

我认为将属性绑定到pojos的推荐方法是使用@EnableConfigurationProperties注释，如下所示：

KafkaConfig.java

@ConfigurationProperties("kafka")
@Data
public class KafkaConfig {
    private String topic;
    private String event;
}

KafkaProducerBeans.java

@Component
@EnableConfigurationProperties(KafkaConfig.class)
public class KafkaProducerBeans {

    private final KafkaConfig kafkaConfig;

    @Autowired
    public KafkaProducerBeans(KafkaConfig kafkaConfig) {
        this.kafkaConfig = kafkaConfig;
    }

    // [...]
}

有关更多详细信息，请参阅Spring官方文档：

• https://docs.spring.io/spring-boot/docs/current/reference/html/features.html#features.external-配置。类型安全配置属性。java bean绑定
• https://docs.spring.io/spring-boot/docs/current/reference/html/features.html#features.external-配置。类型安全配置属性。启用带注释的类型