springboot实现mongodb上传下载

1、上传：

private static Logger log = LoggerFactory.getLogger(MongoDbFSUtil.class);
 
   private static final class MongoInstance {
      public final static MongoClient client;
      static {
         client = new MongoClient("localhost", 27017);
      }
   }
 
   public static MongoDatabase getDatabase(String databaseName) {
      return MongoInstance.client.getDatabase(databaseName);
   }
 
   /**
    * 上传文件
    * @param file
    * @param databaseName
    * @return
    */
   public static String uploadFileToGridFS(File file,String databaseName) {
      InputStream in = null;
      String returnId = null;
      String pathName = file.getPath();
      String[] pathNameArray = pathName.split("\\");
       String[] name = pathNameArray[pathNameArray.length-1].split("\.");
      String filename = name[0];
      String type = name[name.length-1];
      try {
         in = new FileInputStream(file);
         GridFSBucket bucket = GridFSBuckets.create(getDatabase(databaseName));
         GridFSUploadOptions options = new GridFSUploadOptions();
         //设置除filename以为的其他信息
         Document metadata = new Document();
         metadata.append("contentType", type);
         options.metadata(metadata);
//       ObjectId fileId = bucket.uploadFromStream(filename+type, in,options);
         ObjectId fileId = bucket.uploadFromStream("123456", in,options);
         returnId = fileId.toHexString();
         log.info("文件上传成功");
      } catch (IOException e) {
         log.info("upload fail:" + e);
      } finally {
         try {
            in.close();
         } catch (IOException e) {
            log.info("close inputstream fail:" + e);
         }
      }
      return returnId;
   }
另外一种上传：使用

1. @Autowired
2.  
   private GridFsTemplate gridFsTemplate;

UserAO user = (UserAO) SecurityUtils.getSubject().getPrincipal();
Part part = request.getPart("file");
// 获得提交的文件名
String fileName = part.getSubmittedFileName();
// 获得文件输入流
InputStream ins = part.getInputStream();
// 获得文件类型
String contentType = part.getContentType();
// 将文件存储到mongodb中,mongodb 将会返回这个文件的具体信息
GridFSFile gridFSFile = gridFsTemplate.store(ins, fileName, contentType);
FileInfoAO fileInfo = new FileInfoAO();
fileInfo.setContentType(contentType);
fileInfo.setFileName(fileName);
fileInfo.setLastUpdateBy(user != null ? user.getId() : null);
fileInfo.setMongoFileId(gridFSFile.getId().toString());
return ServiceResultHelper.genResultWithSuccess(fileInfo);

2、下载

@RequestMapping("/downLoadFile")
public void downLoadFile(String fileId, HttpServletRequest request, HttpServletResponse response)throws Exception{
    Query query = Query.query(Criteria.where("filename").is("123456"));
    // 查询单个文件
    GridFSDBFile gfsfile = gridFsTemplate.findOne(query);
    if (gfsfile == null) {
        return;
    }
    String fileName = gfsfile.getFilename().replace(",", "");
    //处理中文文件名乱码
    if (request.getHeader("User-Agent").toUpperCase().contains("MSIE") ||
            request.getHeader("User-Agent").toUpperCase().contains("TRIDENT")
            || request.getHeader("User-Agent").toUpperCase().contains("EDGE")) {
        fileName = java.net.URLEncoder.encode(fileName, "UTF-8");
    } else {
        //非IE浏览器的处理：
        fileName = new String(fileName.getBytes("UTF-8"), "ISO-8859-1");
    }
    // 通知浏览器进行文件下载
    response.setContentType(gfsfile.getContentType());
    response.setHeader("Content-Disposition", "attachment;filename="" + "222.png" + """);
    gfsfile.writeTo(response.getOutputStream());



}