Re: HTTPUrlConnection does not download the whole page

From:
The87Boy <the87boy@gmail.com>
Newsgroups:
comp.lang.java.help
Date:
Wed, 3 Feb 2010 10:21:20 -0800 (PST)
Message-ID:
<04207191-e015-4109-8150-0ff282993302@j31g2000yqa.googlegroups.com>
On 3 Feb., 17:25, Lew <no...@lewscanon.com> wrote:

The87Boy wrote:

I have a problem with this code, as you can see in print, where it
prints the error in the page's code:


What error? Why not copy and paste the error message in your post so t=

hat we

can actually have a prayer of helping you?


Actually there are no errors, but it fails when I try to print the
page as the System.err.println is printed inside the
System.out.println

public void print(String link) {

        String page = this.getPage(link);


You don't need to, and shouldn't, prefix member method calls with "this."=

..

For one thing, it's misleading in the presence of overridden methods, or =

if

'this' class doesn't override the method.


I did not know that, but it is easier to do in Netbeans ;)

        try {

            URL url = new URL(link);

            // Open the Connection
            HttpURLConnection conn = (HttpURLConnection)
url.openConnection();

            // Set the information
            conn.setRequestProperty("user_agent", =

  "Mozilla/5.0

(Windows; U; Windows NT 6.0; da-DK; rv:1.9.1.4) Gecko/20091016 Firefox/
3.5.4 (.NET CLR 3.5.30729)");
            conn.setRequestProperty("max_redirects", =

 "0");

            conn.setRequestProperty("timeout", =

   "300");

            conn.setRequestMethod("GET");
            conn.setDoOutput(true);

            // Connect
            conn.connect();

            // Get the Status-Code and add it to the HashMa=

p

            int statusCode = conn.getResponseCode();

            String page = this.getPage(conn.getInputStrea=

m());

            pageEscaped = StringEscapeUtils.unescapeHtml(=

page);

            conn.disconnect();

        } catch (IOException e) {System.err.println(e.getCause
());System.err.println(e.getMessage());}


You problem stems at least in part that you continue blithely along prete=

nding

to process the URL after you catch an exception.

What appears in the error output from this block?


Oh, then I don't know how to make that method correctly

        return pageEscaped;
}

public String getPage(InputStream is) throws IOException {


As a matter of general guidance, public methods often better handle excep=

tions

than pass them upstream. Certainly they should log the error before ha=

ndling

it, and if it must rethrow, often it's better to wrap the low-level excep=

tion

('IOException') in an application-specific exception ('MyAppException').

There are use cases for rethrowing the low-level exception. It depends=

 on the

contract for the method - whether it's a low-level method itself.


Oh, I just thought I was better to catch all exceptions in GUI

        BufferedReader br = new BufferedReader(new InputStrea=

mReader

(is));
        String line = "";


This initialization is never used, so don't initialize 'line' to this val=

ue.

Oh, how is it then initialized in the while?

        StringBuilder sb = new StringBuilder();

        while ((line = br.readLine()) != null) {

            sb.append(line+'\n');


It's a bit strange that you use '\n' as the line terminator when it's app=

arent

from your code example that you're using Windows.


I think I just have to use a line terminator

            System.out.println(line);
        }

        return sb.toString();
}


An alternative formulation for the loop that restricts the scope of 'line=

' to

just the loop is:

   for ( String line; (line = br.readLine()) != null; )
   {
     sb.append( line + System.getProperty( "line.separator" );
     System.out.println(line); // Why?
   }

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