Is there a way to validate @Value in spring boot?

Question

I'm using @Value to inject parameters from my properties file to variable in my application.
Because I'm not the only user in the application and I want to make the injection safety I need to validate the parameter before the injection.

Example:

properties file:

example.string=str1,str2

app.java

@Value(${example.string})
public String example;

the expected behavior in this case for example is to throw an exception because I assume "," id delimiter in array case

score 2 · Accepted Answer · answered Dec 24 '20 at 09:13

I don't think you can directly with @Value. But you could do something like this, which will fail on startup if validation fails:

@Validated
@ConfigurationProperties(prefix="my.prefix")
public class AppProperties {

  //Validation annotations here
  //@NotEmpty
  //@MyCustomValidation
  private String exampleString;


  // getters / setters
}

score 0 · Answer 2 · answered Dec 24 '20 at 09:12

I don't think you can do this before the injection, try to use the post construct method

you can do some thing like that :

@PostConstruct
public void validateValue() {
    if (someProperty.contains(",")) {
        throw new MyException("error");
    }
}

Is there a way to validate @Value in spring boot?

2 Answers2