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open a file

Posted on 1998-07-22
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Last Modified: 2010-03-30
how do you open a file in java when given a filename and directory information?
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Question by:javalearner
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Accepted Solution

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bjornh earned 50 total points
ID: 1227633
Try this to read and print a text file. Dont forget to define variables dir and filename.

try
{
    BufferedReader in = new BufferedReader(new FileReader(dir + filename));
    String s;
    while ((s = in.readLine()) != null)
    {      // Do something with s
    }
    in.close();
} catch(IOException e)
{      // Something went wrong, print error message
}
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Author Comment

by:javalearner
ID: 1227634
i have four methods in my class:  open(), read(), write(), and close().
i just want to have a file open first.  whether to read or write from the file will be determined later, and the actual reading and writing is not done in open().
is this all i need to open a file:
        BufferedReader in = new BufferedReader(new FileReader(dir + filename));
       
should the rest be in my read() method?
       String s;
        while ((s = in.readLine()) != null)
        { // Do something with s
        }
        in.close();
    } catch(IOException e)
    { // Something went wrong, print error message
    }

thanks.
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Expert Comment

by:bjornh
ID: 1227635
I think that should do if you make sure your read method has access to the in-variable, so you have to define it in your class.

This will only work for your read method because you opened your file for reading.

There are lots of other possibilities. I use the book CoreJava, it's quite good though expensive.

Good luck, Bjorn
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