Re: Get a file from the web using java

From:
"Rhino" <no.offline.contact.please@nospam.com>
Newsgroups:
comp.lang.java.help
Date:
Tue, 25 Apr 2006 12:51:36 -0400
Message-ID:
<Ers3g.1157$1V4.81419@news20.bellglobal.com>
"Allan M. Bruce" <allanmb@TAKEAWAYdsl.pipex.com> wrote in message
news:VLidneaCy5nJudPZnZ2dnUVZ8qidnZ2d@pipex.net...

I want to be able to get a file from the web from my java program and read
the contents. How can I do this?

For example, I want to get http://www.somewhere.com/file.txt so that I can
read the contents.


 I _think_ something like the following should work for you:

        /* Create URL pointing at online file. */
        URL textFileUrl = null;
        try {
            textFileUrl = new URL("http://www.somewhere.com/file.txt");
        } catch (MalformedURLException excp) {
            //error handling
        }

            /* Open a stream on the URL. */
        BufferedInputStream bufferedInputStream = null;
        try {
            bufferedInputStream = new
BufferedInputStream(textFileUrl.openStream());
        } catch (IOException io_excp) {
            //error handling
        }

Now, I'm not entirely sure which subclass of InputStream is best for your
data so have a look at the (abstract) java.io.InputStream class and see
which subclass suits you best.

You may also have to futz around with the stream once you get it; there may
be encoding/decoding issues. You will also need to write a loop to get the
data from the stream; that will go something like this:

    byte[] bytes = new byte[102400]; //choose a convenient size for your
array
    int len;
    try {
        while ((len = bufferedInputStream.read(bytes)) != -1) {
            System.out.println("len=" + len); //should write a line for each
arrayful of data it gets
         }
    } catch (IOException io_excp) {
    //error handling
    }

You may want to convert the 'bytes' array to characters and/or strings and
then store it somewhere, like a StringBuffer, as you fill the array each
time.

I would much prefer to read the stream as if it were a text file, one line
at a time, but I don't know of any way to read an online file that way.
There may be a way to read it a line at a time: I just don't know of one.
Then again, there's a lot I don't know.

Sorry, this is not a very complete answer but it should get you started.
With a bit of luck, someone else will jump in if this is the whole wrong
approach!

--
Rhino

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