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From Oleg Kalnichevski <ol...@apache.org>
Subject Re: How to download .jar file? (I think that I read most of threads and googled alot..)
Date Fri, 23 May 2008 09:19:22 GMT
On Thu, 2008-05-22 at 21:46 -0700, JBRyu wrote:
> Hi,
> 
> I have a problem with downloading a .jar file from a HTTP server. I'm now
> using httpclient-4.0-alpha4 and httpcore-4.0-beta1 libraries. I can download
> any .jar file using a http input stream, but the download .jar file is
> corrupted even if the size of the downloaded file is the same as that of the
> original file on the HTTP server so I can't decompress it because it is
> broken. Please see Case #1 for details. So, I use ZipInputStream class for
> reading the compressed file from the HTTP server. However, when I read bytes
> from the ZipInputStream, it always returns -1 at the first time and is
> hanging there. It seems like that the stream is not broken but dosen't do
> anything. Please seee Case #2 for details.
> 
> I spent lots of time but couldn't figure it out. Is there any one who faced
> this problem and resolved it? 
> 
> Thank you for all your helps.
> JB
> 

I do not see any obvious problems with your code aside from that fact
that you should use HttpEntity#getContentLength() method to find out the
length of the incoming content instead of parsing 'content-length'
header manually. 

I wrote this small app to test similar scenario and it worked for me. I
got perfectly valid jar.

==================================

DefaultHttpClient httpclient = new DefaultHttpClient();

HttpGet httpget = new HttpGet(
"http://repo1.maven.org/maven2/org/apache/httpcomponents/httpcore/4.0-beta1/httpcore-4.0-beta1.jar");

System.out.println("executing request: " + httpget.getRequestLine());

HttpResponse response = httpclient.execute(httpget);
HttpEntity entity = response.getEntity();

System.out.println("----------------------------------------");
System.out.println(response.getStatusLine());
if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
    if (entity != null) {
        System.out.println("File size: " + entity.getContentLength());
        
        File file = new File("local.jar");
        
        InputStream instream = null;
        OutputStream outstream = null;
        try {
            instream = entity.getContent();
            outstream = new FileOutputStream(file);
            
            byte[] tmp = new byte[4096];
            int l;
            while ((l = instream.read(tmp)) != -1) {
                outstream.write(tmp, 0, l);
            }
            outstream.flush();
        } finally {
            if (instream != null) {
                instream.close();
            }
            if (outstream != null) {
                outstream.close();
            }
        }
    }
} else {
    if (entity != null) {
        entity.consumeContent();
    }
}

==================================

Oleg

> 
> <Case #1>
> 
> HttpGet httpGet = new HttpGet(httpFilePath);
> HttpResponse response = httpClient.execute(httpGet);
> int responseCode = response.getStatusLine().getStatusCode();
> 
> // Checks the HTTP server response code.
> if ( responseCode ==
> Client_HTTPDownloadConstants.HTTP_RESPONSE_CODE_SUCCESSFUL ) {
>    // Retrieves the target file size from the response header.
>    Header[] headers = response.getHeaders("Content-Length");
>    
>    // Retrieves the target file size.
>    int fileSize = Integer.valueOf(headers[0].getValue());
>    
>    // Prepares an input stream to read the source file bytes from the HTTP
> server.
>    InputStream fis = response.getEntity().getContent();			                    
>    
>    // Prepares a file output stream to write the downloaded bytes to the
> local file.
>    FileOutputStream fos = new FileOutputStream(tmpFilePath)
>    
>    // Initializes the written bytes of the current file.
>    int bytesWritten = 0;
>    
>    // Reads the bytes from the HTTP server.
>    int bytesRead = fis.read(buffer);
>    								    				
>    while (bytesRead != -1) {
>       // Writes bytes to the local file.
>       fos.write(buffer, 0, bytesRead);
>       
>       // Reads bytes from the local file.
>       bytesRead = fis.read(buffer);
>    }
>    							    		        	
>    // Closes the input and output streams.
>    if (fos != null) {
>       fos.flush();
>       fos.close();
>    }
>    if (fis != null) {
>       fis.close();
>    }
> }
> 
> 
> <Case #2>
> 
> HttpGet httpGet = new HttpGet(httpFilePath);
> HttpResponse response = httpClient.execute(httpGet);
> int responseCode = response.getStatusLine().getStatusCode();
> 
> // Checks the HTTP server response code.
> if ( responseCode ==
> Client_HTTPDownloadConstants.HTTP_RESPONSE_CODE_SUCCESSFUL ) {
>    // Retrieves the target file size from the response header.
>    Header[] headers = response.getHeaders("Content-Length");
>    
>    // Retrieves the target file size.
>    int fileSize = Integer.valueOf(headers[0].getValue());
>    
>    // Prepares an input stream to read the source file bytes from the HTTP
> server.
>    InputStream fis = response.getEntity().getContent();			                    
>    
>    // Prepares a ZIP input stream.
>    ZipInputStream zis = new ZipInputStream(fis);
>    
>    // Prepares a file output stream to write the downloaded bytes to the
> local file.
>    FileOutputStream fos = new FileOutputStream(tmpFilePath)
>    
>    // Initializes the written bytes of the current file.
>    int bytesWritten = 0;
>    
>    // Reads the bytes from the HTTP server.
>    int bytesRead = zis.read(buffer);
>    								    				
>    while (bytesRead != -1) {
>       // Writes bytes to the local file.
>       fos.write(buffer, 0, bytesRead);
>       
>       // Reads bytes from the local file.
>       bytesRead = zis.read(buffer);
>    }
>    				    		        	
>    // Closes the input and output streams.
>    if (fos != null) {
>       fos.flush();
>       fos.close();
>    }
>    if (zis != null) {
>       zis.close();
>    }
>    if (fis != null) {
>       fis.close();
>    }
> }
> 
> 
> 
> 
> -- 
> View this message in context: http://www.nabble.com/How-to-download-.jar-file--%28I-think-that-I-read-most-of-threads-and-googled-alot..%29-tp17418619p17418619.html
> Sent from the HttpClient-User mailing list archive at Nabble.com.
> 
> 
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