用于在 java 的 os 文件系统级别管理文件的标准解决方案？

Question

i am working on a web application.we are using java and jsp to upload user files on server and then do some management tasks on them, like checking that every one has only one profile picture (it is not a portal) or there should be only one folder for each user that contains all of its data. so is there any accepted solution, or manifest on how some one should do this, where to use db over file system and so on? thnx

Answer 1

The traditional way of doing, in my experience, it to put all the structured and textual information in database.

Binary files as images, videos, sounds, etc. can be stored in database, but since they can't be queried and are more easily served and backed up from the file system, they're often stored as files.

Answer 2

If you are using relational DB do not store files there. It is possible but it does not might overload your DB. Better way is to store files in file system and references to theses files in DB.

Concerning the directories. If your system is relatively small you can store files in user dedicated directories. It is very convenient for debugging and for implementation of some features like retrieving list of files per user or removing user. The disadvantage of this approach is scalability. File systems typically cannot effectively work with directories that contain millions of files. So the more scalable solution is to create hierarchical structure of directories and fill them until number of files reaches certain threshold, eg 10000 files. In this case create new directory.

If you create 3-5 levels deep directory structure it is scalable enough. Still references to the files are stored in DB. So you can always retrieve files belonging to user utilizing query like

select path from files where user=USER_ID

then iterate over this list in Java and read files if you need.