HDFS and Servlets

[Cesar Delgado <cd...@bigred.unl.edu>]

Does anyone have an example of how I can read a file that lives in HDFS 
from a Servlet?

Thank you for your time,

-Cesar

Re: HDFS and Servlets

[Cesar Delgado <cd...@bigred.unl.edu>]

Ion,

Thanks!  I'll give it a shot in the next couple of days!

-Cesar

Ion Badita wrote:
> Cesar Delgado wrote:
>> Does anyone have an example of how I can read a file that lives in 
>> HDFS from a Servlet?
>>
>> Thank you for your time,
>>
>> -Cesar
> I would use something like this:
> 
>        byte[] buffer = new byte[8192];
> 
>        FileSystem hdfs = FileSystem.get(new Configuration());
>        Path path = new Path("your/path");
>              FSDataInputStream in = hdfs.open(path);
>        ServletOutputStream out = servletResponse.getOutputStream();
> /
> //        you could set the content-type and the length of the file, to 
> help the browser
> //        servletResponse.setContentType("file/contentType");
> //        servletResponse.setContentLength((int)hdfs.getLength(path));/
>          int readed;
>              while((readed = in.read(buffer)) != -1) {
>            out.write(buffer, 0, readed);
>        }
>              in.close();
>        out.flush();
>        out.close();
> 
> 
> You have to make sure that the HDFS is initialized.
> The servletResponse is taken from servlet service or get method.
> 
> I hope this will help you!
> 
> 
> Ion
> 

Re: HDFS and Servlets

[Ion Badita <io...@mcr.ro>]

Cesar Delgado wrote:
> Does anyone have an example of how I can read a file that lives in 
> HDFS from a Servlet?
>
> Thank you for your time,
>
> -Cesar
I would use something like this:

        byte[] buffer = new byte[8192];

        FileSystem hdfs = FileSystem.get(new Configuration());
        Path path = new Path("your/path");
       
        FSDataInputStream in = hdfs.open(path);
        ServletOutputStream out = servletResponse.getOutputStream();
/
//        you could set the content-type and the length of the file, to 
help the browser
//        servletResponse.setContentType("file/contentType");
//        servletResponse.setContentLength((int)hdfs.getLength(path));/
   
        int readed;
       
        while((readed = in.read(buffer)) != -1) {
            out.write(buffer, 0, readed);
        }
       
        in.close();
        out.flush();
        out.close();


You have to make sure that the HDFS is initialized.
The servletResponse is taken from servlet service or get method.

I hope this will help you!


Ion