Spring无配置使用properties文件

@Configuration
@ComponentScan(basePackages="*")
@PropertySource({"classpath:config.properties"})
//@Import(DataSourceConfig.class)
public class DefaultAppConfig {
    @Bean
    public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
        return new PropertySourcesPlaceholderConfigurer();
    }
}

    @Value("${app.name}")
    private String appName;
    @Value("${app.version}")
    private String appVersion;