Reading file problem

Question

Hi all,
I wonder wether I can go beyond my java leve. Here is a stupid problem but could not find it out where in the code ?
I want to read a file where each line will have 2 strings separated by a comma delemiter. for e.g
ABC,DEF
FDG,TYH
GHJ,ABC
my code should read the file in a loop and the first string should go to String variable concept1 and the second string should be the value of Concept2. In my code I could get the first line not beyond that and the error shows :
ABC,DEF
java.util.NoSuchElementException
     at java.util.StringTokenizer.nextToken(StringTokenizer.java:259)
     at GetNodes.main(GetNodes.java:24)
Exception in thread "main"
----jGRASP wedge2: exit code for process is 1.
----jGRASP: operation complete.
my code is :
import java.util.*;
import java.io.*;
public class GetNodes
     static StringTokenizer st;
     static String token="";
     public static void main(String [] args)throws IOException
          String concept1="";
          String concept2="";
          BufferedReader br=new BufferedReader(new FileReader("smita.txt"));
          String line;
          while((line=br.readLine())!=null)
               st=new StringTokenizer(line);
               while(st.hasMoreTokens())
                    concept1=st.nextToken();
                    System.out.println(concept1);
                    while(!concept1.equals(","))
                         token=st.nextToken();
                         concept2=token;
                         System.out.println(concept2);
                         token=st.nextToken();
//concept1=token;
               I know the code is not efficient but that is what at best I can do with my level.
Thanks and apreciate your comments
cheers

Answer 1

the reason you're getting this error is because you're calling your "st.nextToken() twice, if it reached the EOL then it will throw a NoSuchElementException
                    while(!concept1.equals(","))
                         token=st.nextToken();
                         concept2=token;
                         System.out.println(concept2);
                         token=st.nextToken();
               }-- you can use List to store your data from your text file, I modified your code into much simpler way like this:
import java.util.*;
import java.io.*;
public class GetNodes
     static StringTokenizer st;
     static String token="";
     public static void main(String [] args)throws IOException
     List concept=new ArrayList();
     BufferedReader br=new BufferedReader(new FileReader("smita.txt"));
     String line;
     while((line=br.readLine())!=null)
          st=new StringTokenizer(line, ",");
          while(st.hasMoreElements())
               concept.add(st.nextElement()); 
    for (int i = 0; i<concept.size(); i++)
        System.out.println (concept.get(i));
}