logger

logger如果声明是 private 则不能放到方法内比如这样

@Service("iFileService")
public class FileServiceImpl implements FileService {
    public String upload(MultipartFile file, String path) {

        private Logger logger = LoggerFactory.getLogger(FileServiceImpl.class);

        String fileName = file.getOriginalFilename();
        // lastIndexOf 找到.的位置
        String fileExtensionName = fileName.substring(fileName.lastIndexOf(".")+1);
        String uploadFileName = UUID.randomUUID().toString() + "." + fileExtensionName;

这么写就不可以，正确写法

@Service("iFileService")
public class FileServiceImpl implements FileService {

    private Logger logger = LoggerFactory.getLogger(FileServiceImpl.class);
    
    public String upload(MultipartFile file, String path) {
        String fileName = file.getOriginalFilename();
        // lastIndexOf 找到.的位置
        String fileExtensionName = fileName.substring(fileName.lastIndexOf(".")+1);
        String uploadFileName = UUID.randomUUID().toString() + "." + fileExtensionName;
        // {} 为占位符
        logger.info("开始上传文件，上传文件的文件名:{}, 上传的路径:{}, 新文件名:{}", fileName, path, uploadFileName);

        // 如果路径不存在创建路径
        File fileDir = new File(path);
        if (!fileDir.exists()) {
            fileDir.setWritable(true);
            fileDir.mkdirs();
        }