<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-mongodb</artifactId>
</dependency>

spring:
  application:
    name: demo
  data:
    mongodb:
      uri: mongodb://root:你的密碼@localhost:27019
      authentication-database: admin
      database: 你的數(shù)據(jù)庫(kù)

 
import com.mongodb.Block;
import com.mongodb.MongoClient;
import com.mongodb.client.MongoDatabase;
import com.mongodb.client.gridfs.GridFSBucket;
import com.mongodb.client.gridfs.GridFSBuckets;
import com.mongodb.client.gridfs.model.GridFSFile;
import com.mongodb.client.gridfs.model.GridFSUploadOptions;
import com.mongodb.gridfs.GridFS;
import com.mongodb.gridfs.GridFSDBFile;
import org.bson.BsonValue;
import org.bson.Document;
import org.bson.types.ObjectId;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile; 
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.util.*;
   
@RestController
@RequestMapping("/files")
public class FileController {
	private Logger logger = LoggerFactory.getLogger(GridFsServiceImpl.class);
    //匹配文件ID的正則
    private static Pattern NUMBER_PATTERN = Pattern.compile("(?<==).*(?=})"); 
    @Autowired
    GridFsTemplate gridFsTemplate;
    @Autowired
    MongoDbFactory mongoDbFactory;
 
    /**
     * 上傳文件
     *
     * @param file 文件
     * @return 文件名和文件存儲(chǔ)的fileId鍵值對(duì)的Map
     */
    @RequestMapping(value = "/upload", method = RequestMethod.POST)
    public Map<String, ObjectId> upload(@RequestParam(value = "file") MultipartFile file) {
  if(pathId == null || fileType == null || pathId.equals("") || fileType.equals("")){
            logger.debug("上傳文件出錯(cuò)");
            throw new RuntimeException("上傳文件出錯(cuò)：pathId and fileType can not be null");
        }
        Map<String, String> map = new HashMap<>(1);
        String fileName = file.getOriginalFilename();
        //設(shè)置元數(shù)據(jù)
        DBObject metaData = new BasicDBObject();
        metaData.put("userId","1");
        metaData.put("fileExtension",FilenameUtils.getExtension(file.getOriginalFilename()));
        //存儲(chǔ)文件的擴(kuò)展名
       
        try {
            InputStream inputStream = file.getInputStream();
            ObjectId fileId = gridFsTemplate.store(inputStream, fileName,metaData);
            //這個(gè)getFileId是我自己封裝的獲取文件ID的方法
            map.put(file.getOriginalFilename(),getFileId(fileId.toString()));
        } catch (IOException e) {
            logger.debug("上傳文件失敗: "+file);
            throw new RuntimeException("上傳文件失敗："+e.getMessage());
        }
        return map;
    }
 
    /**
     * 通過(guò)文件fileId下載文件
     *
     * @param fileId 文件fileId
     * @param response 文件輸出流
     */
    @RequestMapping(value = "/downLoadByFileId")
    public void downLoadByFileId(@RequestParam(value = "fileId") ObjectId fileId, HttpServletResponse response) {
 GridFSFile gridFsFile = gridFsTemplate.findOne(new Query().addCriteria(Criteria.where("_id").is(fileId)));
        if (gridFsFile != null) {
            // mongo-java-driver3.x以上的版本就變成了這種方式獲取
            GridFSBucket bucket = GridFSBuckets.create(mongoDbFactory.getDb());
            GridFSDownloadStream gridFsDownloadStream = bucket.openDownloadStream(gridFsFile.getObjectId());
            GridFsResource gridFsResource = new GridFsResource(gridFsFile,gridFsDownloadStream);
            String fileName = gridFsFile.getFilename().replace(",", "");
            //處理中文文件名亂碼
            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瀏覽器的處理：
                fileName = new String(fileName.getBytes(StandardCharsets.UTF_8), StandardCharsets.ISO_8859_1);
            }
            response.setHeader("Content-Disposition", "inline;filename=\"" + fileName + "\"");
            response.setContentType(application/octet-stream);
            IOUtils.copy(gridFsResource.getInputStream(), response.getOutputStream());
        }else {
            logger.info("文件不存在");
        } 
    }
    
	/**
     * 根據(jù)文件名查詢文件列表
     * @param fileName 文件名
     * @return
     */
    @RequestMapping("/search")
    public List<Map<String,Object>> search(String filePath, String fileName) {
		//這里返回的是一個(gè)List<Map<String,Object>>
		//因?yàn)镚ridFSFindIterable 迭代出來(lái)的GridFSFile不能直接返回
        GridFSFindIterable gridFSFiles = gridFsTemplate.find(new Query().addCriteria
                (Criteria.where("filename").regex("^.*"+fileName+".*$")));
        return getGridFSFiles(gridFSFiles);
    }
 
    /**
     * 通過(guò)fileId刪除文件
     * @param fileId 文件ID
     * @return 成功為true, 失敗為false
     */
    @RequestMapping("/deleteFilesByObjectId")
    public boolean deleteFilesByObjectId(@RequestParam(value = "fileId") String fileId) {
         try {
            gridFsTemplate.delete(new Query().addCriteria(Criteria.where("_id").is(fileId)));
        }catch (Exception e){
            logger.debug("刪除文件失敗: fileId= "+fileId);
            throw new RuntimeException("刪除文件失?。?+e.getMessage());
        }
    }
	/**
     * 根據(jù)GridFSFiles迭代器返回文件列表，因?yàn)椴荒苤苯臃祷?，所以?xiě)了這個(gè)工具方法
     * @param gridFSFiles 從數(shù)據(jù)庫(kù)取出的文件集合
     * @return List<Map<String,Object>>
     */
    private List<Map<String,Object>> getGridFSFiles(GridFSFindIterable gridFSFiles){
        List<Map<String,Object>> result = new ArrayList<>();
        for (GridFSFile file : gridFSFiles) {
            HashMap<String,Object> map = new HashMap<>(6);
            map.put("fileId",getFileId(file.getId().toString()));
            map.put("fileName",file.getFilename());
            map.put("fileExtension",file.getMetadata().get("fileExtension"));
            map.put("fileSize",file.getLength()/1024);
            map.put("uploadTime",file.getUploadDate());
            map.put("user",file.getMetadata().get("userId"));
            result.add(map);
        }
        return result;
    }
    /**
     * 因?yàn)閺膍ongo中獲取的文件Id是BsonObjectId {value=5d7068bbcfaf962be4c7273f}的樣子
     * 需要字符串截取
     * @param bsonObjectId 數(shù)據(jù)庫(kù)文件的BsonObjectId
     */
    private String getFileId(String bsonObjectId) {
        Matcher m = NUMBER_PATTERN.matcher(bsonObjectId);
        if(!m.find()){
            return bsonObjectId;
        }
        return m.group();
    }
}