springboot使用@value读取配置的方法

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.context.annotation.Configuration;
import org.springframework.stereotype.Component;
@Component
@Configuration
@ConditionalOnProperty(prefix = "spring.option.task", name = "enable", havingValue = "true")
public class OptionTaskConfig {
    private static final Logger LOG = LoggerFactory.getLogger(OptionTaskConfig.class);
    private static String cron;
    public static String getCron() {
        LOG.error("return this.cron = {}!", OptionTaskConfig.cron);
        return OptionTaskConfig.cron;
    }
    @Value("${spring.option.task.cron}")
    public void setCron(String cron) {
        OptionTaskConfig.cron = cron;
    }
}

if (StringUtils.hasLength(OptionTaskConfig.getCron())) {
    LOG.error("有值");
} else {
    LOG.error("空值!");
}