spring boot: how to configure datasource from application properties

Once you have defined data source properties in application.properties in @SpringBootApplication it will auto configure your datasource, so you can remove DataSource configuration. But still if you want to customize your data source configuration then below should work as Environment should give you access of properties:

@Configuration
@PropertySource(value= {"classpath:application.properties"})
public class DatasourceConfig {

    @Autowired
    Environment environment;

    @Bean
    public DataSource datasource() throws PropertyVetoException {
        final DriverManagerDataSource dataSource = new DriverManagerDataSource();
        dataSource.setDriverClassName(environment.getProperty("spring.datasource.driver-class-name"));
        dataSource.setUrl(environment.getProperty("spring.datasource.url"));
        dataSource.setUsername(environment.getProperty("spring.datasource.username"));
        dataSource.setPassword(environment.getProperty("spring.datasource.password"));
        return dataSource;
    }
}

Or if you don't want to access properties via Environment, you can access by @Value

  @Value("${spring.datasource.driver-class-name}")
    private String driverName;

    @Value("${spring.datasource.url}")
    private String url;

    @Value("${spring.datasource.username}")
    private String userName;

    @Value("${spring.datasource.password}")
    private String password;

    @Bean
    public DataSource datasource() throws PropertyVetoException {
        final DriverManagerDataSource dataSource = new DriverManagerDataSource();
        dataSource.setDriverClassName(driverName);
        dataSource.setUrl(url);
        dataSource.setUsername(userName);
        dataSource.setPassword(password);
        return dataSource;
    }