You can configure and change encoding for directories or files including the properties files.
WebStorm lets you change encoding while you work in the editor. If you need to check encoding details and configure more options, use the Editor | Files Encodings page in the Settings/Preferences dialog (Ctrl+Alt+S).
Configure encoding for a directory or a file without built-in encoding information
In the Settings/Preferences dialog (Ctrl+Alt+S), click File Encodings under Editor. The File Encodings page opens.
The Path column shows a path to a file or a directory. The Encoding column shows the encodings. Click the specified encoding to change it. You can also add a new path, delete, or edit the existing one.
Change encoding of a file that contains explicit encoding
Open the desired file in the editor.
Change explicit encoding information. Use error highlighting to recognize wrong encoding and press Ctrl+Space to have a list of available encodings displayed:
Change encoding of a single file that doesn't contain explicit encoding
Open the desired file for editing.
From the main menu, select status bar.or click the file encoding on the
Select the desired encoding from the popup.
If or is displayed next to the selected encoding, it means that this encoding might change the file contents. In this case WebStorm opens a dialog where you can decide what you want to do with the file: choose Reload to load the file in the editor from disk and apply encoding changes to the editor only, or choose Convert to overwrite the file with the encoding of your choice.