Question

I am trying to read from a file with with text as follows and I am not sure why my code is not working.

DHH-2180 110.25

TOB-6851 -258.45

JNO-1438 375.95 CS 145 Computer Science II

IPO-5410 834.15

PWV-5792 793.00

Here is a description of what the class must do:

AccountFileIO

1. Create a class called AccountFileIO in the uwstout.cs145.labs.lab02 package. (This is a capital i then a capital o for input/output.)

a. This class will read data from a file and add it to an AccountList.

2. This class needs no class variables or constructors.

3. Create a method called parseFile that returns an AccountList and takes a file name (String) as a parameter.

CS 145 Computer Science II

This method will read in an input file a line at a time and add any valid account information to an AccountList. The file is formatted so that each line is a separate account. Each line has the format:

<account number> <balance>

The account numbers do not have spaces in them but there is a space between the account number and the balance. See below for an example.

The input files may have errors in them. If a line is incomplete or otherwise corrupted, then it should not be added to the list, but any remaining lines should be processed.

If a line has too much information (i.e. it has values after the balance), any additional information should be ignored.

Create an AccountList that will store the data read in.

Use a Scanner to read from a file with the given file name (the parameter). For each line of input, read in the full line (check the Scanner class to see how to read in an entire line at one time).

With each line, create a new Scanner (use a different variable from the Scanner above) and use that new Scanner to read in the account number and balance. If they are successfully read in, add it to the list.

If the file cannot be opened, then the method should return null.

try-catch blocks will make this easy to do.

Dividing this method into a couple of separate methods may make this easier to do.

4. The AccountFileIO class can be tested by creating a set of files with data expected, calling parseFile and then checking to see if the AccountList returned has the data from the file.

When creating a test file, put it in the project directory and not the package directory. If it is in the project directory, you should be able to do open the file with just the file name.

myFileIO.parseFile("test1.txt");

public Class AccountFileIO{

public AccountList parseFile(String fileName) {

AccountList a=new AccountList();

File file = new File(fileName);

try {

Scanner scanner = new Scanner(file);

int i=0;

while (scanner.hasNext()) {

String[] records = scanner.nextLine().split("\\s+");

scanner.close();

if (records.length >= 2) {

try {

String accountNumber="";

double balance =0.00;

accountNumber=records[0];

a.accts[i].setAccountNum(accountNumber);

balance = Double.parseDouble(records[1]);

a.accts[i].setBalance(balance);

i++;

} catch (NumberFormatException nfe) {

}

}

}

} catch (FileNotFoundException e) {

e.printStackTrace();

return null;

}

return a;

}

public static void main(String[] args) {

AccountFileIO fileIO = new AccountFileIO();

AccountList accounts= fileIO.parseFile("test1.txt");

for (int i = 0; i<accounts.getSize();i++) {

System.out.println(accounts.accts[i]);

}

}

}

Answer 1

The reason why it would not read all records is because you have the scanner.close(); inside the while loop. You should NOT be closing it after reading a single line but at the end of the loop after all records are done. I have deleted the line and just made few simple changes like printing errror message instead of stack trace. Since you have not provided me the AccountList class, I could not run the code.
Please check and let me know if the modified code given below works or not. I am here to help. Let me know through comments. If the answer helped, please do rate it. Thank you.

To indent code in eclipse , select code by pressing ctrl+a and then indent using ctrl+i

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class AccountFileIO{

public AccountList parseFile(String fileName) {
AccountList a=new AccountList();
File file = new File(fileName);

try {

Scanner scanner = new Scanner(file);
int i=0;

while (scanner.hasNext()) {
String[] records = scanner.nextLine().split("\\s+");
if (records.length >= 2) {

try {

String accountNumber="";

double balance =0.00;

accountNumber=records[0];

a.accts[i].setAccountNum(accountNumber);

balance = Double.parseDouble(records[1]);

a.accts[i].setBalance(balance);

i++;

} catch (NumberFormatException nfe) {

}

}

}
scanner.close();

} catch (FileNotFoundException e) {

System.out.println(e.getMessage());
return null;

}

return a;

}

public static void main(String[] args) {

AccountFileIO fileIO = new AccountFileIO();

AccountList accounts= fileIO.parseFile("test1.txt");

for (int i = 0; i<accounts.getSize();i++) {

System.out.println(accounts.accts[i]);

}

}

}