一、新建BeanUtil类

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;

import java.util.ArrayList;
import java.util.List;


@Slf4j
public class BeanUtil implements ApplicationContextAware, DisposableBean {

    private static ApplicationContext applicationContext = null;

    /**
     * 从静态变量applicationContext中取得Bean, 自动转型为所赋值对象的类型.
     */
    public static <T> T getBean(Class<T> requiredType) {
        if(applicationContext==null){
            throw new IllegalStateException("applicaitonContext属性未注入, 请在SpringBoot启动类中注册BeanUtil.");
        }
        return applicationContext.getBean(requiredType);
    }



    @Override
    public void destroy() {
        applicationContext = null;
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        if (BeanUtil.applicationContext != null) {
            log.warn("BeanUtil中的ApplicationContext被覆盖, 原有ApplicationContext为:" + BeanUtil.applicationContext);
        }
        BeanUtil.applicationContext = applicationContext;
    }
}

二、在启动类中注入BeanUtil

@SpringBootApplication
public class StartApplication {

    public static void main(String[] args) {
        SpringApplication.run(StartApplication.class, args);
    }


    @Bean
    public BeanUtil beanUtil() {
        return new BeanUtil();
    }
}

三、在Util类中获取Service

public class MyUtils {

  
    public static UserDetails getCurrentUser() {
        MyUserDetailsService userDetailsService = BeanUtil.getBean(MyUserDetailsService.class);
        //TODO 调用service中的方法处理自己的业务
        return null;
    }
}