spring environment 获取配置信息

使用Environment可以直接获取springboot里的配置信息.

使用例子

@Service
public class KafkaService {

    private final Logger logger = LoggerFactory.getLogger(Application.class);

    Environment env;

    @Autowired
    public KafkaService(Environment env) {
        this.env = env;
    }

    /**
     * 通过kafka admin查看kafka topic 列表
     */
    public Set<String> listTopics() throws Exception {
        Properties properties = new Properties();
        properties.put(AdminClientConfig.BOOTSTRAP_SERVERS_CONFIG, 
                env.getProperty("spring.kafka.consumer.bootstrap-servers"));
        
        System.out.println("connect properties: " + properties);
        AdminClient adminClient = AdminClient.create(properties);

        ListTopicsOptions listTopicsOptions = new ListTopicsOptions();
        listTopicsOptions.listInternal(true);

        Set<String> names = adminClient.listTopics(listTopicsOptions).names().get();
        
        System.out.println("topics:" + names);
        return names;
    }
}

Using Environment Variables in Spring Boot’s Properties Files

还是baeldung的博客整理的比较清晰便捷.

https://www.baeldung.com/spring-boot-properties-env-variables

@value直接获取变量配置

@Value("${baeldung.presentation}")
private String baeldungPresentation;

Environment 获取变量

@Autowired
private Environment environment;

environment.getProperty("baeldung.presentation")

批量管理变量

@Component
@ConfigurationProperties(prefix = "baeldung")
public class BaeldungProperties {

    private String presentation;

    public String getPresentation() {
        return presentation;
    }

    public void setPresentation(String presentation) {
        this.presentation = presentation;
    }
}

@Autowired
private BaeldungProperties baeldungProperties;

baeldungProperties.getPresentation()

在application.yml里使用环境变量

spring:
  datasource:
    url: ${DATABASE_URL}