spring boot application.properties value from bean data

Question

I am working with spring boot. I have properties defined in application.yml.

   spring:
     datasource:
       username: username
       password: password

username and password values are stored externally which program fetches during startup. let's say the bean which fetches them during startup is dbConfig
How can I inject values from dbConfgig to application.yml?

I am using spring-data-jpa autoconfigure which automatically connects to database at startup. I want these values to be loaded to application.yml before spring connects to database.

Do you mean placeholder? https://stackoverflow.com/questions/53273773/spring-boot-usage-of-placeholder-in-application-properties — FakeAlcohol, Nov 13 '20 at 08:06
yes something similar to this. but can I call a function in placeholder? — warrior107, Nov 13 '20 at 08:12
As I know, cannot call a function at application.yaml, why not set the value at your start script?@warrior107 — FakeAlcohol, Nov 13 '20 at 08:19

score 0 · Answer 1 · edited Nov 13 '20 at 11:43

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I think that first, you must create a thread to detect the change at your db Config file and then may you must re-init your bean (data source) to make your change effect.

See: how-to-reinitialize-a-spring-bean

edited Nov 13 '20 at 11:43

JMP

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answered Nov 13 '20 at 08:43

someonewhoisajavadeveloper

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reloading bean is something I can work with. But the problem will be during startup the database connection will be made and it will fail. – warrior107 Nov 13 '20 at 09:56

score 0 · Answer 2 · answered Nov 13 '20 at 09:29

There is no need to inject the user/password in application.yml. You can set them programmatically like this:

@Configuration
public class DataSourceConfig {
    
    @Bean
    public DataSource getDataSource() {
        DataSourceBuilder dataSourceBuilder = DataSourceBuilder.create();
        dataSourceBuilder.driverClassName("org.h2.Driver");
        dataSourceBuilder.url("jdbc:h2:mem:test");
        
        // Take the values from external source, then set them
        dataSourceBuilder.username("username");
        dataSourceBuilder.password("password");
        return dataSourceBuilder.build();
    }
}

I am using spring-boot-cloud-gcp-sql-autoconfigure. This automatically creates a Datasource bean. It takes the username and password from application.yml — warrior107, Nov 13 '20 at 09:57
@warrior107 There is no such thing as `spring-boot-cloud-gcp-sql-autoconfigure`. — , Nov 13 '20 at 12:53

score 0 · Answer 3 · answered Nov 13 '20 at 12:16

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You may also try spring cloud to store properties. And you can then use with the help of placeholders.

https://cloud.spring.io/spring-cloud-config/reference/html/

answered Nov 13 '20 at 12:16

Vipul Pandey

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spring boot application.properties value from bean data

3 Answers3