mongodb的使用和分桶

1、建立连接mongodb

private MongoClient mongoClient;

/**   通过传来的用户名称和密码为空来判断是否需要进行认证连接
     * @param ip
     * @param port
     * @param database
     * @return
     */
    public MongoClient mongoConnection(String ip, int port, String database, String userName, String password) {
        try {
            if (StringUtil.isNotEmpty(ip) && StringUtil.isNotEmpty(database)) {
                MongoClient mongoClient = null;
                if (StringUtil.isNotEmpty(userName) && StringUtil.isNotEmpty(password)) {//开启验证
                    List<ServerAddress> adds = new ArrayList<>();

                    ServerAddress serverAddress = new ServerAddress(ip, port);
                    adds.add(serverAddress);

                    List<MongoCredential> credentials = new ArrayList<>();

                    MongoCredential mongoCredential = MongoCredential.createScramSha1Credential(userName, database,
                            password.toCharArray());
                    credentials.add(mongoCredential);
                    mongoClient = new MongoClient(adds, credentials);
                } else {//不开启验证
                    mongoClient = new MongoClient(ip, port);
                }
                return mongoClient;
            } else {
                return null;
            }
        } catch (Exception e) {
            return null;
        }

    }

2、分桶上传文件到mongodb

 try {
            GridFSBucket bucket = null;
            MongoDatabase db = mongoClient.getDatabase(数据库名称);
            //这里是根据年度分桶的
            if(fiscal != null){
                String name = "test_" + fiscal;
                //创建对应的文件桶
                bucket = GridFSBuckets.create(db,name);
            }else{
                bucket = GridFSBuckets.create(db);
            }
            ByteArrayInputStream input = new ByteArrayInputStream(bytes);
            ObjectId fileId = bucket.uploadFromStream(附件名称, input);
            //上传成功返回的标识fileId
            return fileId.toString();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }

不分桶上传mongodb文件

   try {
            MongoDatabase db = mongoClient.getDatabase(数据库名称);
            GridFSBucket bucket = GridFSBuckets.create(db);
            ByteArrayInputStream inputStream = new ByteArrayInputStream(bytes);
            Object filed = bucket.uploadFromStream(附件名称, inputStream);
            //返回的标识位objectId（fileId）
            return filed.toString();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }

3、分桶读取mongodb上的文件（GridFSDownloadStream本身返回的是InputStream流）

     GridFSDownloadStream gfStream = null;
        try {
            MongoDatabase db = mongoClient.getDatabase(数据库名称);
            //根据年度分桶，如果年度为空去默认的桶里读取文件
            if(fiscal != null){
                String name = "test_" + fiscal;
                GridFSBucket bucket = GridFSBuckets.create(db,name);
                GridFSFindIterable fsFiles = bucket.find(Filters.eq("_id",new ObjectId(fileId)));
                if(fsFiles.iterator().hasNext()){
                     //传来的标识位objectId（fileId）
                    gfStream = bucket.openDownloadStream(new ObjectId(fileId));
                }else {
                    GridFSBucket buckets = GridFSBuckets.create(db);
                    gfStream = buckets.openDownloadStream(new ObjectId(fileId));
                }
            }else {
                GridFSBucket bucket1 = GridFSBuckets.create(db);
                gfStream = bucket1.openDownloadStream(new ObjectId(fileId));
            }
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            //转换流
            downloadToStream(gfStream, out);
            //返回byte数组
            return out.toByteArray();
        } catch (Exception ex) {
            return new byte[0];
        } finally {
            if (gfStream != null) {
                try {
                    gfStream.close();
                } catch (Exception e) {
                }
            }
        }
//转换流
private void downloadToStream(final GridFSDownloadStream downloadStream, final OutputStream destination) {
        byte[] buffer = new byte[downloadStream.getGridFSFile().getChunkSize()];
        int len;
        MongoGridFSException savedThrowable = null;
        try {
            while ((len = downloadStream.read(buffer)) != -1) {
                destination.write(buffer, 0, len);
            }
        } catch (IOException e) {
            savedThrowable = new MongoGridFSException("IOException when reading from the OutputStream", e);
        } catch (Exception e) {
            savedThrowable = new MongoGridFSException(
                    "Unexpected Exception when reading GridFS and writing to the Stream", e);
        } finally {
            if (savedThrowable != null) {
                throw savedThrowable;
            }
        }
    }

不分桶读取文件

 GridFSDownloadStream gfStream = null;
        try {
            MongoDatabase db=mongoClient.getDatabase(数据库名称);
            GridFSBucket bucket = GridFSBuckets.create(db);
            //传来的标识位objectId
            gfStream = bucket.openDownloadStream(new ObjectId(objectId));
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            downloadToStream(gfStream, out);
            if (out.size() == 0) {
                return null;
            }
            return out.toByteArray();
        } catch (Exception ex) {
            return null;
        } finally {
            if (gfStream != null) {
                try {
                    gfStream.close();
                } catch (Exception e) {
                    LOG.error("关闭FS下载流报错:", e);
                }
            }
        }

4、分桶删除文件

 try {
            MongoDatabase db = mongoClient.getDatabase(数据库名称);
            if(fiscal != null){
                String name = "test_" + fiscal;
                GridFSBucket bucket = GridFSBuckets.create(db,name);
                GridFSFindIterable fsFiles = bucket.find(Filters.eq("_id",new ObjectId(fileId)));
                //传来的标识位objectId（fileId）
                if(fsFiles.iterator().hasNext()){
                    bucket.delete(new ObjectId(fileId));
                }else {
                    GridFSBucket buckets = GridFSBuckets.create(db);
                    buckets.delete(new ObjectId(fileId));
                }
            }else {
                GridFSBucket bucket1 = GridFSBuckets.create(db);
                bucket1.delete(new ObjectId(fileId));
            }
        } catch (Exception ex) {
            log.error("delete file error:", ex);
        }

不分桶删除文件

 try {
            MongoDatabase db = mongoClient.getDatabase(数据库名称);
            GridFSBucket bucket = GridFSBuckets.create(db);
            //根据传来的标识位objectId
            bucket.delete(new ObjectId(objectId));
        } catch (Exception e) {
            e.printStackTrace()
            return objectId;
        }