我可以在 Eclipse 的项目资源管理器中生成文件吗？

Question

What I want to do is to write some information in a file, and then generate that file and make it visible right away inside a specific folder in the package explorer. Is that possible and if so how can I generate it exactly in the package explorer (I can do it in Desktop or wherever, ut I would like some insight on this specific case).

Thank you!

Answer 1

That sounds like you should be writing an eclipse plugin. An app can do it to, but there are many caveats:

• It's incredibly convoluted code design. An app is written, and then compiled and packaged, and then run - when run there usually isn't an IDE at all, you run it elsewhere. Conflating these notions and 'breaking the barrier' by having the app write data to 'the source folders' is bizarre.
• It's just not possible to do it without at least having to press F5 ('refresh') on the folder or project, unless you tell eclipse to use the filewatch system, but not all OSes even support it.

So how do I do it?

Aspect 1: Find the location

Given that the 'source' side and the 'compiled' side are supposed to be separate universes, there is no way to 'find' the source folder without hardcoding into your app either the location or the notion 'you were built in standard eclipse and are running within its runner/debugger, therefore, find your own classpath root, go up one, go down to the 'src' dir, and there you go. Make files in this location' - which is hardcoding a lot .

Better option is to use a parameter: Start your application with a parameter or better yet a java environment variable with this data.

Forget about eclipse for a moment, this is basic java:

class Test {
  public static void main(String[] args) {
    System.out.println(System.getProperty("hello.world"));
  }
}

If you then do on the command line:

javac Test.java
java -Dhello.world=TopOfTheMorning Test

Then TopofTheMorning prints. In eclipse's run dialogs you can set VM parameters. Set this one, and use eclipse's variables system to inject the right location:

Menu: Run, Run Configurations...

pick the run config (or make one if needed), and set in the 'VM arguments' block of the 'Arguments' tab -Dsource.folder= , then click 'Variables...', and use container_loc or project_loc . You end up with something like:

-Dsource.folder=${project_loc:your.project.name}

Now, in your app, you can run System.getProperty("source.folder") and now you know where to write!

Aspect 2: Filewatch

Eclipse doesn't have a crystal ball, it doesn't know that a file has just appeared, written by another application (yes, eclipse is running that app, but it is nevertheless another app,). so that file isn't going to magically poof into existence in the Project Explorer, The usual route is to click on some parent of the location where the file now is, and hit F5, which tells eclipse to re-check the directory for new files. then it appears.

However, advanced OSes have this concept called a 'file watcher', which lets you tell the OS, as an application: "Hey, can you give me a quick ping if a file appears in this directory?". Eclipse supports this – but your OS has to support it too!

In the menu: Window, Preferences...

Then, General -> Workspace. There, check the box with 'Refresh using native hooks or polling'.

And then... pray. That isn't guaranteed to actually work. You don't have to write the app first, just make on the command line or in the finder or windows explorer or whatnot any file in the src structure, switch to eclipse, and check if the file just appears within a second or so. If not, that part just doesn't work and you're dead in the water: You must write an eclipse plugin to get this functionality.