How do I configure a Spring Boot datasource from an external properties file defined in the system environment?

Question

I have an environment variable "KBL_APP_PROPS". This exists in both our local Windows environment and the server's LINUX environment. This environment variable points to the Properties file on the system.

I am trying to write a program that uses the indicated properties file to configure the database connection. I have tried several things, and the code below reflects my current rendition.

My database config class

@Configuration
public class DatabaseConfig {
    @Autowired
    Environment env;

    @Bean
    public DataSource getDataSource(@Value("dbUri") String url, @Value("dbUser") String userName, @Value("dbPassword") String password) {
        DataSourceBuilder dataSourceBuilder = DataSourceBuilder.create();
        dataSourceBuilder.driverClassName("oracle.jdbc.driver.OracleDriver");
        dataSourceBuilder.url(url);
        dataSourceBuilder.username(userName);
        dataSourceBuilder.password(password);
        return dataSourceBuilder.build();
    }

    @Bean
    public PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer(/*@Value("${KBL_APP_PROPS}") String fileName*/) {
        PropertySourcesPlaceholderConfigurer properties = new PropertySourcesPlaceholderConfigurer();
        System.out.println(String.format("Env is null %b", env == null));
        properties.setLocation(new FileSystemResource(env.getProperty("KBL_APP_PROPS")/*fileName*/));
        properties.setIgnoreResourceNotFound(false);
        return properties;
    }

My main class

@SpringBootApplication
public class ShortageClaimAutoAccept implements CommandLineRunner {

    private static final Logger log = Logger.getLogger(ShortageClaimAutoAccept.class);

    @Autowired
    JdbcTemplate jdbcTemplate;

//  @Autowired
//  ClaimRepository claimRepository;


    public ShortageClaimAutoAccept() {
    }

    private void startShortageClaimAutoAcceptApp() {
            // This block is for accepting claim details and closing claims
            {
//              List<Claim> claims = claimRepository.findByUnclosedDaysSinceFiled(30);
//              for(Claim claim : claims) {
//                  System.out.println(claim.toString());
//              }
            }
            // This block is for emailing publishers about claims that need to be reviewed
            {

            }
    }

    public static void main(String[] args) {
        try {
            SpringApplication.run(ShortageClaimAutoAccept.class, args);
        } catch (Exception ex) {
            log.fatal("uncaught exception in the process: \n", ex);
        }
    }

    @Override
    public void run(String... arg0) throws Exception {
        startShortageClaimAutoAcceptApp();
    }
}

My program exits with a null pointer exception because env is null.

Your configuration class appears not to be considered for autowiring at all. Otherwise the environment would be assigned or an exception thrown about no suitable bean being found. — Ralf, Mar 06 '20 at 16:02
Thanks, that helped me find https://stackoverflow.com/questions/19421092/autowired-environment-is-null — bcr666, Mar 06 '20 at 17:20

score 0 · Accepted Answer · answered Mar 06 '20 at 17:27

The comment from @Ralf helped me find a SO article where the @Autowire isn't being called for some things. So I changed my DatabaseConfig to use EnvironmentAware.

@Configuration
public class DatabaseConfig implements EnvironmentAware {
    Environment environment;

    @Override
    public void setEnvironment(final Environment environment) {
        this.environment = environment;
    }

    @Bean
    public DataSource getDataSource(@Value("${dbUri}") String url, @Value("${dbUser}") String userName, @Value("${dbPassword}") String password) {
        DataSourceBuilder dataSourceBuilder = DataSourceBuilder.create();
        dataSourceBuilder.driverClassName("oracle.jdbc.driver.OracleDriver");
        dataSourceBuilder.url(url);
        dataSourceBuilder.username(userName);
        dataSourceBuilder.password(password);
        return dataSourceBuilder.build();
    }

    @Bean
    public PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
        PropertySourcesPlaceholderConfigurer properties = new PropertySourcesPlaceholderConfigurer();
        properties.setLocation(new FileSystemResource(environment.getProperty("KBL_APP_PROPS")));
        properties.setIgnoreResourceNotFound(false);
        return properties;
    }
}

How do I configure a Spring Boot datasource from an external properties file defined in the system environment?

1 Answers1