To provide nicer logging when a Spring property is invalid

Question

Using a application.properties file my Spring Boot app can use some property values in it. A way to make sure a mandatory value must present is to add an annotation @Value for the property. The problem with this is the app fails miserably if the property value is not there in the properties file.

I am after a nicer less horrible way to say printing out a log line about "Property A is missing" instead of a whole stack trace. Is there a way to do this while still using @Value to initialise the properties? For example, property A is mandatory, an error is logged before app exits; property B is missing but not mandatory, a warning is logged and app continues.

Shailesh Chandra · Accepted Answer · 2019-11-06T11:44:18.263

2

If you can identify all property, then you can write a method in Application class with @Postconstruct, and inside your method, you can manually validate and log them

@Autowired
    private Environment environment;

    @PostConstruct
    private void validateProperties() {

        environment.getProperty(key);
        .....
        ......
    }

Alternatively, you can write your custom EnvironmentPostProcessor, and iterate all properties and log whichever is null/empty.

edited Nov 06 '19 at 11:44

answered Nov 06 '19 at 05:47

Shailesh Chandra

2,164
2
17
25

Thanks. But I am not reading from the environment, I am reading from application.properties file. – user1589188 Nov 06 '19 at 06:00
Spring automatically populates **application.properties** in environment – Shailesh Chandra Nov 06 '19 at 06:01

score 0 · Answer 2 · answered Nov 06 '19 at 07:25

As you're using spring-boot consider creating a @ConfigurationProperties class rather than using the @Value annotation.

By doing that you can do your validations using Bean Validation, also in the same class, you can implement the interface InitializingBean and add extra validations/log messages as you with.

Follow this link on Spring's official docs to read more about @ConfigurationProperties.

To provide nicer logging when a Spring property is invalid

2 Answers2