<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
  <property name="location" value="dev.properties" />
</bean>

@Value("${tag}")
private String tag;

<bean id="appConfig" class="org.springframework.beans.factory.config.PreferencesPlaceholderConfigurer">
  <property name="location" value="dev.properties" />
</bean>

@Value("${tag}")
private String tag;

  <bean id="config" class="org.springframework.beans.factory.config.PropertiesFactoryBean">
    <property name="location" value="dev.properties" />
  </bean>

@Value("#{config['tag']}")
private String tag;

@Value("#{config['tag']}")
private String tag;

<bean id="appConfig" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
  <!--<property name="location" value="classpath:${env}.properties" />-->
  <property name="properties">
    <props>
      <prop key="tag">123</prop>
    </props>
  </property>
</bean>

@Value("${tag}")
private String tag;