Java: Create a File Object from URL (without downloading)

URL.getFile

04.10.2008 at 08:48AM PDT, ID: 21326102

Rank: Genius

http://java.sun.com/javase/6/docs/api/java/net/URL.html#getFile()

04.10.2008 at 08:49AM PDT, ID: 21326115

that returns a string - not a File Object

http://java.sun.com/j2se/1.4.2/docs/api/java/net/URL.html

04.10.2008 at 08:52AM PDT, ID: 21326148

Rank: Sage

File is a reference of the resource in the local file system and URL is a reference of a resource in remote or local system. So you will be able to create URL from File but the reverse is not possible unless you write the URL resource locally and then create File reference of it!

04.10.2008 at 08:59AM PDT, ID: 21326235

Thanks for the clarification ksivanath.

So, if i have an *applet* running on www.whatever.com, trying to create a File object from www.whatever.com/images/thisImage.jpg - this isn't possible?

04.10.2008 at 09:01AM PDT, ID: 21326258

Rank: Genius

>>that returns a string - not a File Object

Well only a String is meaningful. The file(File) resides elsewhere.

What is your objective?

04.10.2008 at 09:02AM PDT, ID: 21326263

Rank: Sage

nope, u need to write that locally and then refer it as File!

04.10.2008 at 09:02AM PDT, ID: 21326270

Rank: Sage

locally --> local disk!

04.10.2008 at 09:04AM PDT, ID: 21326298

Rank: Genius

>>trying to create a File object from ...

Why do you *want* to create a File object?

04.10.2008 at 09:07AM PDT, ID: 21326321

Rank: Genius

Also

>>So, if i have an *applet* running on www.whatever.com

the applet won't be running there (probably). The applet runs on the machine of whomever's looking at it

04.10.2008 at 09:10AM PDT, ID: 21326358

CEHJ:

Objective: Metaphile (http://sourceforge.net/projects/metaphile) is a Java package that basically reads metadata from image files. It requires a File object. I want to use it in a web-based environment, in an applet. All images are "local" - local to the server where the applet was launched. like i wrote earlier, if the applet is running on www.whatever.com, all images are in www.whatever.com/images. I need to pass it a File object from within an applet . . .

04.10.2008 at 09:13AM PDT, ID: 21326385

CEHJ:

(sorry, you're right, the applet isn't "running on" www.whatever.com - it was launched from there (or whatever the appropriate vocabulary is). anyway, the project involves reading metadata, using metaphile, in an applet environment.)

04.10.2008 at 09:17AM PDT, ID: 21326443

Rank: Genius

Reading metadata from a remote URL is a piece of cake if that's what you want to do...

04.10.2008 at 09:18AM PDT, ID: 21326465

Rank: Genius

... and you can do that without using a file e.g.

                       
             InputStream metaDataIn = getClass().getResourceAsStream("metadata.xml");

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04.10.2008 at 09:26AM PDT, ID: 21326559

Rank: Sage

>>getClass().getResourceAsStream("metadata.xml");

CEHJ, I think, the asker is using a openesourced java called metafile which reads metadata from image file if you pass the image as File instasnce to them... in such case, this is not appropriate. your code will be useful if he has a file in the jar and want to read!

04.10.2008 at 09:29AM PDT, ID: 21326590

the metadata is embedded in the image . . . does that make a difference? i've attached a file if you'd like to try. the XMP metadata is as follows:

- CopyrightNotice: 2006
- Keywords: book, Senior Library 2006, bird, orange
- Document Title: To Kill a Mockingbird
- Author: Richard Smith
- Description: To Kill a Mockingbird book cover

test.jpg (51 KB) (File Type Details)

JPG with embedded XMP metadata

04.10.2008 at 09:35AM PDT, ID: 21326674

Rank: Genius

Just get the stream as i mentioned and you'll be able to get the contents, including this sort of stuff:

                       
             <?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
        <key>com.apple.print.PageFormat.PMHorizontalRes</key>
................................................

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04.10.2008 at 09:35AM PDT, ID: 21326680

if you dl the image and open it in photoshop you get something like the attached image. getting at this data is no simple task, hence rather robust libraries like metaphile. all images in www.whatever.com/images contain embedded metadata, which i need to access through an applet . . . and metaphile only takes File objects . . .

metadataForTest.jpg (320 KB) (File Type Details)

Metadata for test.jpg

04.10.2008 at 09:42AM PDT, ID: 21326765

Rank: Genius

>>and metaphile only takes File objects

Unfortunate and bad design. Do you have a link to this API?

04.10.2008 at 09:47AM PDT, ID: 21326808

Sourceforge project: http://sourceforge.net/projects/metaphile

code examples: http://www.miniturismo.co.uk/metaphile/example01.php
- also see (on the same site) example02.php, example03.php, example04.php, example05.php

04.10.2008 at 10:15AM PDT, ID: 21327098

Rank: Genius

Since they haven't seen fit to give you an InputStream ctor, you'll have to create a temporary file. Web Start would be less strict than an applet.

If you can get hold of the source (can't see it there) you can fix it easily enough. Or get them to do it ;-)

04.10.2008 at 10:36AM PDT, ID: 21327350

Rank: Sage

whats the problem for you to write the file locally from applet?

04.10.2008 at 10:47AM PDT, ID: 21327437