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get the word by position

kumaraswamy adurthi
Greenhorn

Joined: Sep 27, 2005
Posts: 11
hi

i have a flat file , in that i have date field , i know the row and column of this date my question is can i get this date by using this column number and row number in java

please help me out

thanks and regards

kumaraswamy adurthi
Santhosh Kumar
Ranch Hand

Joined: Nov 07, 2000
Posts: 242
Java on its own does not provide that type of capability. What you asking for is functionality of DBMS systems. You need to program yourself to read that row and columns.

If you use Oracle, there is a feature called external files where in you can map a flat file as table. So you can query it as any other table.
Ulf Dittmer
Marshal

Joined: Mar 22, 2005
Posts: 39535
    
  27
If you know the structure of the file precisely, and since you know the row and column, it may be possible to calculate the offset of the date field from the beginning of the file. With that offset you can either use RandomAccessFile or FileInputStream.skip() to access that position directly.

If the fields have varying lengths, and are not padded to fixed length, then this is not possible.


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John Calabasas
Greenhorn

Joined: Jun 11, 2006
Posts: 17
If its a file with line breaks and delimiters (ex, csv) between column values, I think it will be possible to use a combination of iterating over rows using readLine() and iterating over columns using Scanner.next() or String.split() or Regex to achieve the purpose. However this may not be a good approach in case the file is very big.

If the file contains fixed width columns, then you can try using RandomAccessFile.seek() to take you to the appropriate value using some math.

If its a delimited file which is not too big, another option will be to read and populate a 2-dim String Array from the file and read directly using the co-ords.
[ July 04, 2006: Message edited by: John Calabasas ]

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