无法使用 @Value 在 Springboot 的 application.yaml 中读取值。

huangapple
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英文:

Not able to read values using @Value in application.yaml in Springboot

问题

  1. 我正在使用Spring Boot - 2.3.3.RELEASE。在application.yaml中有一些值，我正在尝试使用@Value注解将它们注入到类中。但出于某些原因，它们没有被加载。结果应该是在SendPhoneByPhoneNumbers.java中，我们应该能够从application.yaml中读取notificationServiceURL。
  3. 注意- 我正在使用工厂和策略模式。该项目将被其他项目用作库，以导入并使用服务层公开的方法。
  5. 这是文件夹结构：https://i.stack.imgur.com/jpbNj.jpg
  6. 我正在尝试通过以调试模式运行Demo.java来查看实际值的外观。
  8. application.yaml

notificationService:
url: "https://someURL.com"

  2. Demo.java

@EnableAutoConfiguration(exclude={DataSourceAutoConfiguration.class})
@SpringBootApplication
public class Demo {

  1. public static void main(String[] args) {
  3.     SpringApplication.run(Demo.class, args);
  5.     String title="Title";
  6.     String message="message";
  7.     List<String> phoneNumbers = new ArrayList<>();
  8.     phoneNumbers.add("333-222-1111");
  9.     PhoneService phoneService = new PhoneService();
  10.     phoneService.sendNotificationByPhoneNumbers(title, message, phoneNumbers);
  12. }

}

  2. PhoneService.java

@Service
public class PhoneService {

  1. PhoneServiceImpl notificationServiceImpl = new PhoneServiceImpl();
  3. public void sendNotificationByPhoneNumbers(String title, String message, List<String> phoneNumbers) {
  4.     notificationServiceImpl.sendNotificationByPhoneNumbers(title, message, phoneNumbers);
  5. }

}

  2. PhoneServiceImpl.java

@Slf4j
@Component
public class PhoneServiceImpl {

  1. @Value("${notificationService.url}")
  2. String url;
  4. public void sendNotificationByPhoneNumbers(String title, String message, List<String> phoneNumbers) {
  5.     PhoneContext phoneContext = new PhoneContext(new SendPhoneByPhoneNumbers(url));
  6.     phoneContext.notify(title, message, phoneNumbers);
  7. }

}

  2. PhoneContext.java

public class PhoneContext {

  1. private PhoneStrategy phoneStrategy;
  3. public PhoneContext(PhoneStrategy phoneStrategy){
  4.     this.phoneStrategy = phoneStrategy;
  5. }
  7. public void notify(String title, String message, List<String> employees){
  8.     phoneStrategy.sendNotification(title, message, employees);
  9. }

}

  2. PhoneStrategy.java

public interface PhoneStrategy {

public void sendNotification(String title, String message, List listOfEmployeeIdGroupNamePhoneNumbers);
}

  2. SendPhoneByPhoneNumbers.java

@Slf4j
public class SendPhoneByPhoneNumbers implements PhoneStrategy {

  1. RestTemplate restTemplate;
  2. String notificationServiceURL;
  3. BuildHttpRequest buildHttpRequest;
  5. public SendPhoneByPhoneNumbers(String notificationServiceURL) {
  6.     this.notificationServiceURL = notificationServiceURL;
  7.     this.restTemplate = new RestTemplate();
  8.     this.buildHttpRequest = new BuildHttpRequest();
  9. }
  11. @Async
  12. public void sendNotification(String title, String message, List<String> phoneNumbers) {
  13.     SmsMessage smsMessage= new SmsMessage(title, message, phoneNumbers, Collections.emptyList(), Collections.emptyList());
  15.     try {
  16.         HttpHeaders headers = new HttpHeaders();
  17.         headers.set("idToken", buildHttpRequest.getNewToken());
  19.         HttpEntity<SmsMessage> newRequest = new HttpEntity<>(smsMessage, headers);
  20.         restTemplate.postForObject(notificationServiceURL + "/someUrl", newRequest, String.class);
  21.     } catch (Exception e) {
  22.         log.error(e.getMessage());
  23.     }
  24. }

}

  2. 此外，如果您对修改代码/结构以使其更好的方式有任何建议，请务必提出。
  4. 提前致谢。
英文:

I'm using Spring boot - 2.3.3.RELEASE. There are some values in application.yaml which I'm trying to inject in the classes using @Value annotation. But for some reason, they are not loading up. The result should be that, in SendPhoneByPhoneNumbers.java, we should be able to read notificationServiceURL from application.yaml.

Note- I'm using Factory and Strategy pattern. This project is going to be used as a Library for other projects to import and use the methods exposed by Service layer.

Here is the folder structure: https://i.stack.imgur.com/jpbNj.jpg
I'm trying to test by running Demo.java in Debug mode to see how the actual values looks like.

application.yaml

  1. notificationService:
  2.   url: &quot;https://someURL.com&quot;

Demo.java

  1. @EnableAutoConfiguration(exclude={DataSourceAutoConfiguration.class})
  2. @SpringBootApplication
  3. public class Demo {
  5.     public static void main(String[] args) {
  7.         SpringApplication.run(Demo.class, args);
  9.         String title=&quot;Title&quot;;
  10.         String message=&quot;message&quot;;
  11.         List&lt;String&gt; phoneNumbers = new ArrayList&lt;&gt;();
  12.         phoneNumbers.add(&quot;333-222-1111&quot;);
  13.         PhoneService phoneService = new PhoneService();
  14.         phoneService.sendNotificationByPhoneNumbers(title, message, phoneNumbers);
  16.     }
  17. }

PhoneService.java

  1. @Service
  2. public class PhoneService {
  4.     PhoneServiceImpl notificationServiceImpl = new PhoneServiceImpl();
  6.     public void sendNotificationByPhoneNumbers(String title, String message, List&lt;String&gt; phoneNumbers) {
  7.         notificationServiceImpl.sendNotificationByPhoneNumbers(title, message, phoneNumbers);
  8.     }
  9. }

PhoneServiceImpl.java

  1. @Slf4j
  2. @Component
  3. public class PhoneServiceImpl {
  5.     @Value(&quot;${notificationService.url}&quot;)
  6.     String url;
  8.     public void sendNotificationByPhoneNumbers(String title, String message, List&lt;String&gt; phoneNumbers) {
  9.         PhoneContext phoneContext = new PhoneContext(new SendPhoneByPhoneNumbers(url));
  10.         phoneContext.notify(title, message, phoneNumbers);
  11.     }
  13. }

PhoneContext.java

  1. public class PhoneContext {
  3.     private PhoneStrategy phoneStrategy;
  5.     public PhoneContext(PhoneStrategy phoneStrategy){
  6.         this.phoneStrategy = phoneStrategy;
  7.     }
  9.     public void notify(String title, String message, List&lt;String&gt; employees){
  10.         phoneStrategy.sendNotification(title, message, employees);
  11.     }
  12. }

PhoneStrategy.java

  1. public interface PhoneStrategy {
  3.    public void sendNotification(String title, String message, List&lt;String&gt; listOfEmployeeIdGroupNamePhoneNumbers);
  4. }

SendPhoneByPhoneNumbers.java

  1. @Slf4j
  2. public class SendPhoneByPhoneNumbers implements PhoneStrategy {
  4.     RestTemplate restTemplate;
  5.     String notificationServiceURL;
  6.     BuildHttpRequest buildHttpRequest;
  8.     public SendPhoneByPhoneNumbers(String notificationServiceURL) {
  9.         this.notificationServiceURL = notificationServiceURL;
  10.         this.restTemplate = new RestTemplate();
  11.         this.buildHttpRequest = new BuildHttpRequest();
  12.     }
  14.     @Async
  15.     public void sendNotification(String title, String message, List&lt;String&gt; phoneNumbers) {
  16.         SmsMessage smsMessage= new SmsMessage(title, message, phoneNumbers, Collections.emptyList(), Collections.emptyList());
  18.         try {
  19.             HttpHeaders headers = new HttpHeaders();
  20.             headers.set(&quot;idToken&quot;, buildHttpRequest.getNewToken());
  22.             HttpEntity&lt;SmsMessage&gt; newRequest = new HttpEntity&lt;&gt;(smsMessage, headers);
  23.             restTemplate.postForObject(notificationServiceURL + &quot;/someUrl&quot;, newRequest, String.class);
  24.         } catch (Exception e) {
  25.             log.error(e.getMessage());
  26.         }
  27.     }
  28. }

Also, if you guys have any suggestions on modifying the code/structure in an way to make it better, please do suggest.

Thanks in advance.

答案1

得分: 1

  1. PhoneService phoneService = new PhoneService();

由于您使用的 PhoneService 不是 Spring 容器中的托管bean，所以值没有被注入。

代码改进和修复

  1. String title = "Title";
  2. String message = "message";
  3. List<String> phoneNumbers = new ArrayList<>();
  4. phoneNumbers.add("333-222-1111");
  5. // PhoneService phoneService = new PhoneService();
  6. phoneService.sendNotificationByPhoneNumbers(title, message, phoneNumbers);

将此代码移动到实现了 CommandLineRunner 或 ApplicationRunner 接口的类中，并覆盖相应的 run() 方法。在该类中，您可以使用 @Autowired 注入 PhoneService，而不是手动实例化它。另外请注意，您需要在这个类上标记 @Component 注解。

其他建议的小改动：

  1. 您可以将 SendPhoneByPhoneNumbers 类设置为单例。如果有多个实现，请使用 @Qualifier。
  2. RestTemplate 和 BuildHttpRequest 都可以使用 @Bean 注解创建。
  3. 由于您正在使用 lombok，考虑使用 @RequiredArgsConstructor 也是一个选择。
英文: 
  1. PhoneService phoneService = new PhoneService();

Since PhoneService that you are using is not a managed bean by spring container, the values are not being injected.

Code Improvement and FIX

  1. String title=&quot;Title&quot;;
  2.         String message=&quot;message&quot;;
  3.         List&lt;String&gt; phoneNumbers = new ArrayList&lt;&gt;();
  4.         phoneNumbers.add(&quot;333-222-1111&quot;);
  5.         // PhoneService phoneService = new PhoneService();
  6.         phoneService.sendNotificationByPhoneNumbers(title, message, phoneNumbers);

Move this code to a class implementing CommanLineRunner or ApplicationRunner and override corresponding run(). In this class, you could @Autowire PhoneService rather than manually instantiating it. Also note that you have to mark this class with @Component

Other minor suggested changes:

  1. You can make SendPhoneByPhoneNumbers class a singleton. If there are multiple implementions, use @Qualifier
  2. Both RestTemplate and BuildHttpRequest could be created using @Bean annotation.
  3. Since you are using lombok, using @RequiredArgsConstructor could also be considered.

huangapple
  • 本文由 发表于 2020年10月14日 02:36:32
  • 转载请务必保留本文链接：https://go.coder-hub.com/64341203.html
  • java
  • spring
  • spring-boot
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