java.io.IOException: Premature EOF

[Eva Lin]

Hi guys!

I am getting a java.io.IOException: Premature EOF - for some urls, yet different on each execution - after executing the following function. Any ideas?

public static void urlReader(String url, String path, String fileName) {
        String inputLine = null;
        
        URL x = null;
        BufferedReader in = null;
        
        createFile(path, fileName);

        try {
            // Create file
            FileWriter fwstream = new FileWriter(path + fileName);
            BufferedWriter out = new BufferedWriter(fwstream);

            x = new URL(url);
            in = new BufferedReader(new InputStreamReader(x.openStream()));

            while ((inputLine = in.readLine()) != null) {

                if (inputLine.length() > 0) {
                    //System.out.println(inputLine + "\n");
                    out.write(inputLine + "\n");
                }
            }

            // Close the input stream
            in.close();

            // Close the output stream
            out.close();
        } catch (IOException ex) {
            System.out.println(ex);
            System.out.println("Application aborted while function \"urlReader();\" was executing!");
            System.out.println("url = \"" + url + "\"\n");
            System.out.println("inputLine = \"" + inputLine + "\"\n");
            //System.exit(-1);
        }
    }

[Joe Ess]

You didn't give us the exception stack trace, which is a vital piece of debugging information, but your problem sounds like this post

[Eva Lin]

Joe Ess wrote:You didn't give us the exception stack trace, which is a vital piece of debugging information, but your problem sounds like this post

Thanks for your reply.
I am not enough familiar with the debugging process. So i would appreciate if you could provide me further information on how to carry out the following change: "...not to read using BufferedReader but one byte at a time and put the read in a try-catch for EOFException. ".

Kind regards,
Eva Lin.

[Eva Lin]

No one?

Please, tell me what you mean when you talk about "I think the straight forward solution will be, not to read using BufferedReader but one byte at a time and put the read in a try-catch for EOFException."! And how can I give you the exception stack trace?

[Joe Ess]

Eva Lin wrote:And how can I give you the exception stack trace?

Introduction to Java Stack Traces

[Evan Caballero]

Please, tell me what you mean when you talk about "I think the straight forward solution will be, not to read using BufferedReader but one byte at a time and put the read in a try-catch for EOFException."! And how can I give you the exception stack trace?

instead of using

 while ((inputLine = in.readLine()) != null)

try

 while ((inputChar = in.read()) != -1)

where inputChar is declared as a int or a char.

[Eva Lin]

Okay. Here we are!

I added the following command (i.e. ex.printStackTrace();) inside the catch block in order to show you the stack trace.
I really concern about the behavior of my application because the "stuck" comes from different urls in each execution...
Also, it is worth to notice that, after the installation of netBeans and the app-execution in a new machine, the app completed successfully!
But, this doesn't happen again! What the !@#$ is going on? How can I solve the bug?
Some guys told me about Thread.wait(1000); function but neither this worked out!
@Evan Caballero: can you explain with details what you mean?

run:
Application aborted while function "urlReader();" was executing!
java.io.IOException: Premature EOF
java.io.IOException: Premature EOF
        at sun.net.www.http.ChunkedInputStream.readAheadBlocking(ChunkedInputStream.java:538)
        at sun.net.www.http.ChunkedInputStream.readAhead(ChunkedInputStream.java:582)
        at sun.net.www.http.ChunkedInputStream.read(ChunkedInputStream.java:669)
        at java.io.FilterInputStream.read(FilterInputStream.java:116)
        at sun.net.www.protocol.http.HttpURLConnection$HttpInputStream.read(HttpURLConnection.java:2512)
        at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:264)
        at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:306)
        at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:158)
        at java.io.InputStreamReader.read(InputStreamReader.java:167)
        at java.io.BufferedReader.fill(BufferedReader.java:136)
        at java.io.BufferedReader.readLine(BufferedReader.java:299)
        at java.io.BufferedReader.readLine(BufferedReader.java:362)
        at x.application.urlReader(application.java:429)
        at x.application.downloadPages(application.java:410)
        at x.application.main(application.java:46)
Java Result: -1
BUILD SUCCESSFUL (total time: 2 minutes 10 seconds)

[Evan Caballero]

try this :

public static void urlReader(String url, String path, String fileName) {
        int inputByte = -1;
        
        URL x = null;
        BufferedReader in = null;
        
        createFile(path, fileName);

        try {
            // Create file
            FileWriter fwstream = new FileWriter(path + fileName);
            BufferedWriter out = new BufferedWriter(fwstream);

            x = new URL(url);
            in = new BufferedReader(new InputStreamReader(x.openStream()));

            while ((inputByte = in.read()) != -1) {
            	out.write(inputByte);
            }

            // Close the input stream
            in.close();

            // Close the output stream
            out.close();
        } catch (IOException ex) {
            System.out.println(ex);
            System.out.println("Application aborted while function \"urlReader();\" was executing!");
            System.out.println("url = \"" + url + "\"\n");
            System.out.println("inputByte = \"" + ((char) inputByte) + "\"\n");
            //System.exit(-1);
        }
    }

[Eva Lin]

Nope.
Exactly the same behavior...
About 4 out of 84 pages (urls) refuse to completely downloaded....
No hope....

[Evan Caballero]

If the purpose of your application is to "download" pages over HTTP, you should take a look at HttpURLConnection. There are plenty of examples on the internet to show you how to use it.

[Eva Lin]

Evan Caballero wrote:If the purpose of your application is to "download" pages over HTTP, you should take a look at HttpURLConnection. There are plenty of examples on the internet to show you how to use it.

Yes. This is actually what i want...
Do you mean a modification like this one:

public static void urlReader(String url, String path, String fileName) {
        try {
            FileWriter fwstream = new FileWriter(path + fileName);
            BufferedWriter out = new BufferedWriter(fwstream);

            URL x = new URL(url);
            URLConnection c = x.openConnection();
            //Spoof the connection so we look like a web browser
            c.setRequestProperty( "User-Agent", "Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0; H010818)" );

            BufferedReader in = new BufferedReader(new InputStreamReader(c.getInputStream()));

            String inputLine = null;

            while ((inputLine = in.readLine()) != null) {

                if (inputLine.contains("<span class=\"title\"><a href=\"/")) {
                    out.write(inputLine + "\n");
                }
            }
            // Close the input stream
            in.close();

            // Close the output stream
            out.close();
        } catch (IOException ex) {            
            System.out.println("Application aborted while function \"urlReader();\" was executing!");
            System.out.println(ex);
            ex.printStackTrace();
            System.exit(-1);
        }
    }

[Evan Caballero]

HttpURLConnection conn = (HttpURLConnection) x.openConnection(); is better I think ;)

[Eva Lin]

No.
Neither this does work...
As a newbie, I am not familiar with the stack trace.
Is there any way of using this kind information?

[Joe Ess]

Evan Caballero wrote:HttpURLConnection conn = (HttpURLConnection) x.openConnection(); is better I think ;)

To my knowledge, all the Java API HTTP/HTTPS classes use the same sun.* classes under the covers. If you have a problem with one, you'll have a problem with all.
this guy looks like he solved the problem by switching to the Apache HttpClient.