跨平台方式询问用户的文档文件夹？

Question

I'm writing a cross-platform program in Java and want to stick the configuration files in the user's documents folder ("My Documents" under Windows, "Documents" under appropriate Linux, and whatever the folder's called under Mac OS), but I'm not sure how to ask Java for that.

I'd like to stay away from hard-coding things (do X if we're on Windows, Y if we're on Linux, or Z if we're on OS X), as this puts the burden of support on my shoulders rather than the Oracle development team.

I've checked the system properties list, but it doesn't seem to include the user's documents folder.

Answer 1

Sadly there is no easy cross-platform way. You will have to take advantage of native functionality on each OS platform

• Here is some info on how to do it in osx
• Here is some info on how to do it in windows

For Linux I don't have a convenient link, but given that there isn't necessarily the concept of a Documents folder in Linux, I don't know of a good solution. The system property user.home should at least be valid in Linux.

Answer 2

Partial solution:

boolean isMac = System.getProperty("os.name").equals("Mac OS X");

Or use http://commons.apache.org/vfs/ to get the operating system: http://commons.apache.org/vfs/apidocs/org/apache/commons/vfs2/util/Os.html

// the folder name is the same whatever the language of Mac OSX.

Mac: System.getProperty("user.home")+File.separator+"Documents");

/Users/david/Documents

Win: System.getenv("APPDATA"));

C:\\Documents and Settings\\david\\Application Data

Answer 3

Ask the user, somehow, where they want to save data to, or use the current directory (simple relative paths) and provide appropriate instructions for set up. One means of "asking" is having a property that can be set via the command line.

Don't just pollute the user's home directory with your application's stuff - how do you know how they like their document tree organized?

I am absolutely fed up with *nix oriented programs dropping their little config files and data folders into the root of my documents folder.

Answer 4

This is usually not possible in a generic way. You will have to use platform dependent apstractions. I do it like this for AppData eg, on Windows I detect the AppData/Roaming or AppData/Local, depending on the data I need to store, on other Platforms I create a folder ".myappname" in the userhome, and use this.

For the documents folder, you will have to read the registry. Before Windows Vista using the user.home propery + "/Documents" is not enought, because in other languages it might be "/Dokumente" (german) or something else. Just the registry has the real path to this folder.

On linux platforms it depends on the Desktop environment. You will just have to try it out. Gnome and KDE use different places to store the Documents folder, IMHO. And if you just use FVWM there, there is no predefined place for docs except the user.home property, what is a good fallback.

Answer 5

Assuming this is an application which requires installation, Why not ask the user to specify the location during installation. Generate a run script using this information which would set the appropriate environment variables. As a norm the user is not expected to run the java command!

When the user starts the application using this run script, the application can read the environment variables.

Alternatively, create a jar file with configuration files. Read the config files using Classloader's getResourceAsStream. As long as the configuration jar is under the classpath you can access the files. This also has the added advantage of hiding the configuration from accidental modification. This should work for folders as well (if the config needs to be modified by the user).

Answer 6

What is wrong with hardcoding a way to get the path depending on the users operating system? There can be large variances and OS's work differently with different names. Simply on launch find the path of the documents folder based on their OS and continue to reference that path wherever it is needed.