SpringBoot中用原来常用的@AutoWire注入，debug是空

1.我们使用这个工具类在。很多工具类中都有包含比如

<dependency>
    <groupId>cn.hutool</groupId>
    <artifactId>hutool-all</artifactId>
    <version>5.3.0</version>
</dependency>

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;

/**
 * @author bo bo
 * @date 2020/4/18 10:12
 * @desc
 */
public final class SpringUtil implements ApplicationContextAware {
    private static ApplicationContext applicationContext = null;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        // TODO Auto-generated method stub
        if (SpringUtil.applicationContext == null) {
            SpringUtil.applicationContext = applicationContext;
            System.out.println(
                    "========ApplicationContext配置成功," +
                            "在普通类可以通过调用ToolSpring.getAppContext()获取applicationContext对象,applicationContext="
                            + applicationContext + "========");
        }
    }

    public static ApplicationContext getApplicationContext() {
        return applicationContext;
    }

    //通过
    public static Object getBean(String name) {
        return getApplicationContext().getBean(name);
    }

    //通过class获取Bean.
    public static <T> T getBean(Class<T> clazz) {
        return getApplicationContext().getBean(clazz);
    }
}

2.实际使用，在你的业务代码里MqttService是我要用的类

MqttService service = SpringUtil.getBean(MqttService.class); service.xxx（）； //你的service中的方法