Java:Reading text file

chetah · #1 October 5th, 2008, 02:21 AM

bd.txt
D2333 How to program in Java r IN 454554 Dietal & Dietal Prentice Hall
G4547 Java in a Nut Shell c 343345 David Flagman O'Reilly 03-02-08
END

678764 John Smith #5 Hill View, Rose Hall Undergrad 5
END

//end of sample data
1. data elements are separated by Tabs
problems
1. When I try to read the text file as is give an error. I try to use "useDelimiters" but I cannot find out what the symbol for the Tab-key. However, If I take the spaces from the data for example JohnSmith, then It would read. I can read the first part of the file but unable to get the second part to read. Note: there is no date for the first line of data, this also generates an error, but this is how the data was given to me.

Expand|Select|Wrap|Line Numbers

 public class Book{

 private String ISBN;

 private String title;

 private String   type;

 private String status;

 private int    borrowerId;

 private String author;

 private String publisher;

 private String dateBorrowed;
 
 public Book( String isb, String tit, String typ, String sta, int borrid, String aut, String pub, String dat){

  ISBN          = isb;

  title    = tit;

  type          = typ;

  status        = sta;

  borrowerId    = borrid;

  author        = aut;

  publisher     = pub;

  dateBorrowed  = dat;
 
 }//End of Constructor

public class Borrower{

 private int borrowerId;

 private String borrowerName;

 private String borrowerAddress;

 private String borrowerStatus;

 private int    borrowerNoBooks;
 
 public Borrower( int id ){

  borrowerId        = id;

  borrowerName      = name;

  borrowerAddress   = address;

  borrowerStatus    = status;

  borrowerNoBooks   = noBooks;
 
 }//End of Borrower's Constructor 
 
import java.io.*;

import java.util.*;

class Test{

 static Book[]book = new Book[100];

 static Borrower[]borrower = new Borrower[100];

 public static void main( String[] args )throws IOException{
 
  Scanner in = new Scanner( new FileReader ( "db.txt" ) );

  Scanner me = new Scanner( new FileReader ("db.txt" ) );//Is there a more efficient way than using the Scanner twice?
 
  String v = in.next();

  int i = 0; //Iteratror for array
 
  while(!(v.equals("END"))){

   book[i] = new Book(v, in.next(), in.next(), in.next(), in.nextInt(), in.next(), in.next(), in.next());

   i++;

   v = in.next();

   if(v.equals("END")){//Breaks out of the loop when the first end is encountered

    break;

   }

  }//End of while 
 
      int count = 0;
 
  while(me.hasNext()){//Not getting this part to read it is generating a mismatch error

   if(me.hasNextInt()){

    borrower[count] = new Borrower(in.nextInt());

    count++;

   }else{

    String l = me.next();

    if(l.equals("END")){

     break;

    }

   }

  }
 
  in.close();

  me.close();
 
   for(int j = 0; j < i; j++){

    System.out.println(book[j].toString());

   }

Laharl · #2 October 5th, 2008, 04:17 AM

The tab character is usually '\t'.

chetah · #3 October 6th, 2008, 10:53 AM

bd.txt
D2333 How to program in Java r IN 454554 Dietal & Dietal Prentice Hall
G4547 Java in a Nut Shell c 343345 David Flagman O'Reilly 03-02-08
END

678764 John Smith #5 Hill View, Rose Hall Undergrad 5
657933
END

chetah · #4 October 6th, 2008, 11:05 AM

bd.txt
D2333 How to program in Java r IN 454554 Dietal & Dietal Prentice Hall
G4547 Java in a Nut Shell c 343345 David Flagman O'Reilly 03-02-08
END

678764 John Smith #5 Hill View, Rose Hall Undergrad 5
END

Thank you very much, the tab works fine. The above is an example of the data I am working with. Having gotten the tab to work, reading in the data becomes a problem. Tell me am I going wrong.

Expand|Select|Wrap|Line Numbers

 
String v = input.next() //read first value in data

int count = 0;

while(!(v.equals("END")))// check for end

{

     book[count] = new Book (v, input.next() etc.)

     count++;

     v = input.next();

     if(v.equals("END"){

         break;

     }}
 
     int x = input.nextInt()

      while(x!=0){

           borrower[i] = new Borrower(etc.)

           i++;

          x = input.nextInt();

         String p = input.next()

         if(p.equals("END"){

               break;

         }}

What is wrong with my logic here? Even if I get the file to compile, when I try to print I get null.

Nepomuk · #5 October 7th, 2008, 02:11 PM

Quote:

Originally Posted by chetah

bd.txt
D2333 How to program in Java r IN 454554 Dietal & Dietal Prentice Hall
G4547 Java in a Nut Shell c 343345 David Flagman O'Reilly 03-02-08
END

678764 John Smith #5 Hill View, Rose Hall Undergrad 5
END

Thank you very much, the tab works fine. The above is an example of the data I am working with. Having gotten the tab to work, reading in the data becomes a problem. Tell me am I going wrong.

Expand|Select|Wrap|Line Numbers

 
String v = input.next() //read first value in data

int count = 0;

while(!(v.equals("END")))// check for end

{

     book[count] = new Book (v, input.next() etc.)

     count++;

     v = input.next();

     if(v.equals("END"){

         break;

     }}
 
     int x = input.nextInt()

      while(x!=0){

           borrower[i] = new Borrower(etc.)

           i++;

          x = input.nextInt();

         String p = input.next()

         if(p.equals("END"){

               break;

         }}

What is wrong with my logic here? Even if I get the file to compile, when I try to print I get null.

OK, fist of all: Both r035198x and I have now added [CODE]...[/code] to your posts. Please use them yourself from now on.

Now, where do you try to print something and what printout would you expect? Oh, and I'm not sure if you know that, but input.next() will read the next Word (so whatever comes until the next whitespace character) and not more. You may want to use input.nextLine().

Greetings,
Nepomuk

Java:Reading text file

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