javafx-文件的URI和absolutepath之间的区别

Question

I wanted to use an absolute path for Image URL in javafx . this gives me a way to do that .

File file = new File(System.getProperty ("user.dir")+ "\\profile" + "\\chat3.png");
    System.out.println(file);
    System.out.println(file.toURI().toURL().toExternalForm());

These codes generate the following output:

C:\\Users\\myUsername\\Downloads\\Compressed\\15Dec\\profile\\chat3.png file:/C:/Users/myUsername/Downloads/Compressed/15Dec/profile/chat3.png

what is the difference between these two lines?

Answer 1

The file.toURI() handles special character conversions, so in general calling file.toURI().toURL() is a better option since it will convert for example white spaces to %20 , For example if file name is "chat version 3.png" converts to :

file:/C:/Users/myUsername/Downloads/Compressed/15Dec/profile/chat%20version3.png

Answer 2

Both lines point to the same resource file, they just use different syntaxes to do so.

C:\\Users\\myUsername\\Downloads\\Compressed\\15Dec\\profile\\chat3.png

Is an MS-DOS style file path .

It is a syntax used by Windows for identifying a file location. Other operating systems will use a different format (for instance Unix uses forward slashes rather than back slashes).

file:/C:/Users/myUsername/Downloads/Compressed/15Dec/profile/chat3.png

Is a Uniform Resource Identifier (URI) . It conforms to a standard syntax for identifying a resource. The URI is a standard format and not specific to a given operating system (it will always use forward slashes).

In this case the URI type is a Uniform Resource Locator (URL) that identifies a resource accessed via the file protocol at the provided path. The syntax for a URI is:

scheme:[//[user:password@]host[:port]][/]path[?query][#fragment]

To understand more, read the linked articles.