代码

 final BulkOperations bulkOps = fsMongoTemplate.bulkOps(BulkOperations.BulkMode.UNORDERED, FsFile.class);
        List<FsFile> entries = fsMongoTemplate.find(new Query().addCriteria(Criteria.where("owner").is(1588232816247L)), FsFile.class);
        entries.stream().filter(entry -> entry != null).forEach(entry -> {
            Query query = new Query();
            query.addCriteria(Criteria.where("fid").is(entry.getFid()));
            Update update = new Update();
            update.set("path", String.valueOf(Math.random()));
            bulkOps.updateOne(query, update);
        });
        BulkWriteResult result = bulkOps.execute();

处理结果

{"deletedCount":0,"insertedCount":0,"matchedCount":6,"modifiedCount":6,"modifiedCountAvailable":true,"upserts":[]}

测试结果

path长度为更新字符串长度