JAVA Spring Boot : How to access application.properties values in normal class

Question

I know how I can access the application.properties values in @Service classes in Java Spring boot like below

@Service
public class AmazonClient {

    @Value("${cloud.aws.endpointUrl}")
    private String endpointUrl;
}

But I am looking for an option to access this value directly in any class (a class without @Service annotation)

e.g.

public class AppUtils {
      @Value("${cloud.aws.endpointUrl}")
      private String endpointUrl;
}

But this returns null. Any help would be appreciated. I have already read here but didn't help.

maybe @Autowired private Environment env;? I know it's not the same, but... — Alberto
– Alberto, Commented Apr 15, 2021 at 10:32

Igor Amelin · Accepted Answer · 2021-04-15 11:02:36Z

10

There's no "magic" way to inject values from a property file into a class that isn't a bean. You can define a static java.util.Properties field in the class, load values from the file manually when the class is loading and then work with this field:

public final class AppUtils {
    private static final Properties properties;

    static {
        properties = new Properties();

        try {
            ClassLoader classLoader = AppUtils.class.getClassLoader();
            InputStream applicationPropertiesStream = classLoader.getResourceAsStream("application.properties");
            applicationProperties.load(applicationPropertiesStream);
        } catch (Exception e) {
            // process the exception
        }
    }
}

answered Apr 15, 2021 at 11:02

Igor Amelin

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6 Comments

Kishan Solanki Over a year ago

This worked. But everytime when any function called from AppUtils class, then I am accessing like this properties.getProperty("cloud.aws.endpointUrl") , I hope this doesn't lead to memory leak

code_mechanic Over a year ago

@KishanSolanki One follow up question, how would you create the AppUtils object in your code?

Igor Amelin Over a year ago

1. This code doesn't lead to memory leak. The static block where we load properties from the file runs only once when this class is loaded by JVM. So if you start your application and use this class, the last one shouldn't be loaded again.

stebak Over a year ago

@IgorAmelin there seems to be an error in the code provided, shouldn't it be properties.load(applicationPropertiesStream); instead? Also are you able to update your answer and include the static method you made mention of above?

Steve Over a year ago

But using this approach will potentially introduce bugs if you use application-<profile>.properties where Spring intelligently reads properties that are overridden based on what profile is loaded. In this suggested utility, it will only ever look in the root application.properties file.

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Pang · Accepted Answer · 2023-12-08 05:59:57Z

3

You can easily achieve this by annotating your app utils class with @component annotation. Spring will take care of loading properties.

But if you don't want to do that approach, then look at the link below.

https://www.baeldung.com/inject-properties-value-non-spring-class

edited Dec 8, 2023 at 5:59

Pang

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answered Apr 15, 2021 at 10:50

Praveen Gowthaman

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