Spring Boot @Value Properties

Question

I have a Spring Boot application and in one of the classes, I try to reference a property from the application.properties file using @Value. But, the property does not get resolved. I have looked at similar posts and tried following the suggestions, but that didn't help. The class is:

@Configuration @ComponentScan @EnableAutoConfiguration public class PrintProperty {    @Value("${file.directory}")   private String fileDirectory;    public void print() {     System.out.println(fileDirectory);   } } 

I have the property file.directory in application.properties. I have other fields as well.

Answer 1

I had the same problem like you. Here's my error code.

@Component public class GetExprsAndEnvId {     @Value("hello")     private String Mysecret;       public GetExprsAndEnvId() {         System.out.println("construct");     }       public void print(){         System.out.println(this.Mysecret);     }       public String getMysecret() {         return Mysecret;     }      public void setMysecret(String mysecret) {         Mysecret = mysecret;     } } 

This is no problem like this, but we need to use it like this:

@Autowired private GetExprsAndEnvId getExprsAndEnvId; 

not like this:

getExprsAndEnvId = new GetExprsAndEnvId(); 

Here, the field annotated with @Value is null because Spring doesn't know about the copy of GetExprsAndEnvId that is created with new and didn't know to how to inject values in it.

Answer 2

Make sure your application.properties file is under src/main/resources/application.properties. Is one way to go. Then add @PostConstruct as follows

Sample Application.properties

file.directory = somePlaceOverHere 

Sample Java Class

@ComponentScan public class PrintProperty {    @Value("${file.directory}")   private String fileDirectory;    @PostConstruct   public void print() {     System.out.println(fileDirectory);   } } 

Code above will print out "somePlaceOverhere"