问在新的抽象类中使用时，@Autowired字段为null

EN

@Component
public class MessageUtil {

    @Autowired
    @Qualifier("processMessages")
    private ReloadableConfig config;
    
    public String createMessage() {
        return config.getPropertyStr("message.simple.signature");
    }
}

<bean id="processMessages" class="com.company.framework.resources.ReloadableConfig">
    <property name="basename" value="classpath:com/company/aaa/bbb/domain/service/processMessages"/>
    <property name="defaultEncoding" value="UTF-8"/>
    <property name="cacheSeconds" value="60"/>
</bean>

public abstract class MessageBuilder {
    @Autowired
    @Qualifier("processMessages")
    protected ReloadableConfig config;
    
    public abstract String createMessage();
}

@Component
public class SimpleMessageBuilder extends MessageBuilder {
    private String template;

    private void setTemplate() {
        template = config.getPropertyStr("message.simple.signature");
    }

    @Override
    public String createMessage() {
        setTemplate();
        return template;
    }
}