my.db.user=postgres
my.db.password=root
my.db.url=jdbc:postgresql://localhost:5432/mydb

import com.zaxxer.hikari.HikariDataSource;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;

@Configuration
public class DatabaseConfig {

    @Bean
    @Primary
    @ConfigurationProperties("spring.datasource")
    public HikariDataSource dataSource() {
        return DataSourceBuilder.create()
                .type(HikariDataSource.class)
                .build();
    }
}