* open a SequenceFile.Reader on the sequence file
* in a loop, call next(key,val) on the reader to read the next key/val pair
in the file (see: http://hadoop.apache.org/**common/docs/current/api/org/**
apache/hadoop/io/SequenceFile.**Reader.html#next(org.apache.**
hadoop.io.Writable,%20org.**apache.hadoop.io.Writable)<http://hadoop.apache.org/common/docs/current/api/org/apache/hadoop/io/SequenceFile.Reader.html#next(org.apache.hadoop.io.Writable,%20org.apache.hadoop.io.Writable)>
)
* write code to format the key & val into whatever appropriate format you
want, and write them to the console
* when next(key,val) returns false, exit the loop
did you have some kind of a permission problems when you tried reading the
file with SequenceFile.Reader ?
i keep getting this error:
Exception in thread "main" java.io.FileNotFoundException:
C:\cygwin\home\closedItemSet\output0 (Access is denied)
and just can't work around it.
Thanks
On Thu, Sep 8, 2011 at 1:52 AM, Lance Norskog <[email protected]> wrote:
> You might find it more easy to understand this if you use one of the
> low-level job-scripting languages like Oozie or Hamake. They put the whole
> assemblage of stuff into one file.
>
> On Wed, Sep 7, 2011 at 3:17 PM, David Rosenstrauch <[email protected]>wrote:
>
>> * open a SequenceFile.Reader on the sequence file
>> * in a loop, call next(key,val) on the reader to read the next key/val
>> pair in the file (see: http://hadoop.apache.org/**
>> common/docs/current/api/org/**apache/hadoop/io/SequenceFile.**
>> Reader.html#next(org.apache.**hadoop.io.Writable,%20org.**
>> apache.hadoop.io.Writable)<http://hadoop.apache.org/common/docs/current/api/org/apache/hadoop/io/SequenceFile.Reader.html#next%28org.apache.hadoop.io.Writable,%20org.apache.hadoop.io.Writable%29>)
>> * write code to format the key & val into whatever appropriate format you
>> want, and write them to the console
>> * when next(key,val) returns false, exit the loop
>>
>> HTH,
>>
>> DR
>>
>>
>> On 09/07/2011 06:10 PM, ilyal levin wrote:
>>
>>> Can you be more specific on how to perform this. In general is there a
>>> way
>>> to convert the binary files i have to text files?
>>>
>>>
>>>
>>> On Tue, Sep 6, 2011 at 11:26 PM, David Rosenstrauch<[email protected]**
>>> >wrote:
>>>
>>> On 09/06/2011 01:57 AM, Niels Basjes wrote:
>>>>
>>>> Hi,
>>>>>
>>>>> In the past i've had the same situation where I needed the data for
>>>>> debugging. Back then I chose to create a second job with simply
>>>>> SequenceFileInputFormat, IdentityMapper, IdentityReducer and finally
>>>>> TextOutputFormat.
>>>>>
>>>>> In my situation that worked great for my purpose.
>>>>>
>>>>>
>>>> I did similar at my last job, but rather than writing a 2nd map/reduce
>>>> job
>>>> for this, we just wrote a simple command line app that used the Hadoop
>>>> Java
>>>> API to dump the contents of the binary file as text (JSON) to the
>>>> console.
>>>>
>>>> HTH,
>>>>
>>>> DR
>>>>
>>>
>
>
> --
> Lance Norskog
> [email protected]
>
>
