问题描述：SpringBoot项目中需要上传文件到当前服务器的磁盘（即物理地址），返回可访问的路径给前端。前端利用路径显示文件内容。
开发环境：SpringBoot2.0以上、JDK 1.8

1.在springboot中加入下面代码

@Value("${file.uploadFolder}")
private String uploadFolder;
@Bean
MultipartConfigElement multipartConfigElement() {
MultipartConfigFactory factory = new MultipartConfigFactory();
factory.setLocation(uploadFolder);
return factory.createMultipartConfig();
}
自定义MVC文件映射

@Configuration
public class WebMvcConfig implements WebMvcConfigurer {
@Value("${file.staticAccessPath}")
private String staticAccessPath;

@Value("${smas.captrue.image.path}")
private String captureImagePath;

@Value("${file.uploadFolder}")
private String uploadFolder;

@Override
public void addCorsMappings(CorsRegistry registry) {
registry.addMapping("/").allowedOrigins("").allowCredentials(true).allowedMethods("").maxAge(3600);
}

@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
registry.addResourceHandler(staticAccessPath).addResourceLocations("file:" + uploadFolder + captureImagePath);
}

}
文件上传

@RequestMapping(path = "/files")
@RestController
public class FileController {

@Value("${smas.captrue.image.path}")
private String captureImagePath;

@Value("${file.uploadFolder}")
private String uploadFolder;

@Value("${file.uri}")
private String uri;

@RequestMapping(value = "/upload")
public FileVo emailUpload(HttpServletRequest request) {
MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;
Map<String, MultipartFile> files = multipartRequest.getFileMap();
String path_deposit = uploadFolder + captureImagePath;

List<String> urls = new ArrayList<>();
for (Map.Entry<String, MultipartFile> entry : files.entrySet()) {
  try {
    String fileName = entry.getValue().getOriginalFilename();
    FileHandleUtil.upload(entry.getValue().getInputStream(), path_deposit, fileName);
    urls.add(FileHandleUtil.getServerIPPort(request) + File.separator + uri + fileName);
  } catch (IOException e) {
    throw new SmasException("文件读取异常");
  }
}

FileVo fileVo = new FileVo();
fileVo.setErrno("0");
fileVo.setData(urls);

return fileVo;

}
}
在application.properties中增加以下配置

图片临时路径#单个数据的大小spring.servlet.multipart.maxFileSize=10Mb#总数据的大小spring.servlet.multipart.maxRequestSize=10Mb#文件上传后存储路径：D:\home\capture\5*.jpg(具体配置如下)#访问Url:http://ip:port/smas/upload/#文件上传目录(window是d/e/f盘， linux是/)（注意Linux和Windows上的目录结构不同）#file.uploadFolder=/file.uploadFolder=d://# 设备截图文件保存路径(文件存在具体的文件夹的路径)smas.captrue.image.path=home/capture/#静态资源对外暴露的访问路径(访问图片的路径)file.staticAccessPath=/upload/*#浏览器访问file.uri=smas/upload/

文件处理工具类

public class FileHandleUtil {

/**

• 上传单个文件
• @param inputStream 文件流
• @param path 文件路径，如：image/
• @param filename 文件名，如：test.jpg
• @return 成功：上传后的文件访问路径，失败返回：null
  */
  public static String upload(InputStream inputStream, String path, String filename) {
  //创建文件夹
  createDirIfNotExists(path);
  //存文件
  File uploadFile = new File(path, filename);
  try {
  FileUtils.copyInputStreamToFile(inputStream, uploadFile);
  } catch (IOException e) {
  throw new SmasException("文件上传失败！");
  }
  return uploadFile.getPath();
  }

/**

• 创建文件夹路径
  */
  private static void createDirIfNotExists(String path) {
  File file = new File(path);
  if (!file.exists()) {
  file.mkdirs();
  }
  }

/**

• 删除文件
• @param path 文件访问的路径upload开始 如：/upload/image/test.jpg
• @return true 删除成功；false 删除失败
  */
  public static boolean delete(String path) {
  File file = new File(path);
  return file.exists() == true ? file.delete() : true;
  }

/**

• 获取服务部署根路径 http:// + ip + port
• @param request
• @return
  */
  public static String getServerIPPort(HttpServletRequest request) {
  //+ ":" + request.getServerPort()
  return request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort();
  }
  }