Java Scanner is not working while reading a file

Question

public class Test {

    static private Scanner x;

    public static void main(String args[])
    {
        try {
            x=new Scanner(new File("C:\\Users\\scoda\\workspace\\Nikhil\\src\\chinese.txt"));
            x.useDelimiter(" ");
            while(x.hasNext())  
            {

                String a=x.next();
                String b=x.next();              
                String c=x.next();
                System.out.println(a+b+c);

            }
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

My input file is

12 karthik kk
23 gg gg

Expected output:

12karthikkk
23gggg

Actual output:

12karthikkk
23
java.util.NoSuchElementException
    at java.util.Scanner.throwFor(Unknown Source)
    at java.util.Scanner.next(Unknown Source)

I am trying to debug the issue from a long time . Help is appreciated.

personally I would read the whole line and then split on " " — Scary Wombat
– Scary Wombat, Commented Jan 16, 2017 at 1:56
I tried printing a,b,c inside loop it prints fine but at the end it shows the exception — karthik gorijavolu
– karthik gorijavolu, Commented Jan 16, 2017 at 2:02
Is it possible that the scanner detects that there is something beyond the last "gg", for example a newline? That would mean that String = x.next() would cause the exception. Would you place a counter before the loop and see whether the exception occurs at iteration 4? (start at 1, print before the Scanner#next() calls.) EDIT: basically what shmosel says. — synchronizer
– synchronizer, Commented Jan 16, 2017 at 2:07

shmosel · Accepted Answer · 2017-01-16 02:06:13Z

4

Because you changed the delimiter to space, the newline isn't counted as a separator, and there are actually only 5 tokens in your string:

12
karthik
kk

23
gg
gg

Your code is throwing an exception on the second call to String c=x.next();, because there is no sixth token. If you remove the x.useDelimiter(" "); statement, it will use the default whitespace delimiter, which will split on your newline as well, resulting in 6 tokens.

answered Jan 16, 2017 at 2:06

shmosel

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1 Comment

karthik gorijavolu Over a year ago

Thanks a lot , Understood my mistake.

prasanna sudharsan · Accepted Answer · 2017-01-16 06:27:36Z

0

Try this

  StringBuffer buffer = new StringBuffer(10);
        try
        {
            x = new Scanner(new File("D:\\test1.txt"));
            x.useDelimiter(" ");

            while (x.hasNext())
            {

                String a = x.next();
                buffer.append(a);

            }
        }
        catch (Exception e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        System.out.println(buffer.toString());
    }

answered Jan 16, 2017 at 6:27

prasanna sudharsan

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