关于解决Application failed to start with classpath；SpringBoot的service无法注入bean的问题

和网上大多数不同，我是日志文件的两个包倒错了，应该是
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class UserService {
    private static final Logger logger = LoggerFactory.getLogger(UserService.class);