Develop Reference

Retrieve lines in txt file and append new inputs from the user java

I'm using an arraylist to append inputs and send the arraylist elements to file. However, everytime I exit the program and run it again, the contents in the written in the file becomes empty.
ArrayList<String> memory = new ArrayList<String>();
public void fileHandling() {
try {
FileWriter fWriter = new FileWriter("notes.data");
for (int x = 0; x <= memory.size() - 1; x++) {
fWriter.write(memory.get(x) + '\n');
}
fWriter.close();
} catch (IOException e) {
System.out.println(e);
}
}
public void createNote() {
Scanner insertNote = new Scanner(System.in);
LocalDate todayDate = LocalDate.now();
LocalTime nowTime = LocalTime.now();
String timeFormat = nowTime.format(DateTimeFormatter.ofLocalizedTime(FormatStyle.MEDIUM));
String dateTime = todayDate.toString() + " at " + timeFormat;
while (true) {
System.out.println();
System.out.println("Enter a note");
System.out.print("> ");
String note = insertNote.nextLine();
if (note == null) {
System.out.println("Invalid input! Try again");
break;
} else {
memory.add(note + " /" + dateTime);
fileHandling();
System.out.println("Note is saved!\n");
break;
}
}
I expect the program to save the contents of every input. Then if I exit and run the program again, the contents will go back to the array

Your code currently does the following:
You enter something (X) for the first time:
It gets added to the ArrayList
The ArrayList gets written into the file
Your file now contains: X
You enter something second (Y):
It gets added to the ArrayList (Which now contains: X, Y)
The ArrayList gets written into the file
Your file now contains: X + newline + Y
Your Problem is, that everytime you create a new FileWrite it overwrites your file.
This can be avoided by using the constructor like this:
FileWriter writer = new FileWriter("notes.data", true);
This sets it into the append mode and therefore keeps previous data in the file

You don't need to create a separate Scanner, in method createNote(), in order to get a "note" from the user.
It is usually better to write your code using the interface rather than the specific implementation because then you usually need to change less code if you decide to change the implementation. Hence the type for member variable memory should probably be List rather than ArrayList.
Note that ArrayList may waste memory if the list of "note"s is large. I suggest using LinkedList instead. Alternatively, use an array (rather than a List) and handle expanding the array when adding a "note" as well as reducing the array when removing a "note".
Having an infinite loop, i.e. while (true), which contains a single if-else where both the if block and the else block contain break statements, means that the loop will perform exactly one iteration. May as well remove the while loop – which means also removing the break statements.
Rather than writing the code that generates a timestamp repeatedly, you should adopt the DRY principle and extract that code into a separate method.
The file name should be a constant so as to minimize the amount of code changes you will need to do if you decide to change the file name.
By convention, text files have a filename extension of .txt whereas binary files have the .data extension.
Although you don't need to, I personally prefer to initialize class member variables in the constructor.
The below code is a SSCCE, hence I added a main method. More notes appear after the code.
package Methods;
import java.util.*;
import java.time.format.*;
import java.time.*;
import java.io.*;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
public class FileSys {
private static final String FILENAME = "notes.txt";
private static final String CREATE = "C";
private static final String DELETE = "D";
private static final String FIND = "F";
private static final String QUIT = "Q";
private static final String SHOW = "S";
private static final String UPDATE = "U";
Scanner reader;
List<String> memory;
public FileSys() throws IOException {
reader = new Scanner(System.in);
memory = new LinkedList<String>();
loadFile();
}
public void fileHandling() {
Path path = Paths.get(FILENAME);
try (BufferedWriter bw = Files.newBufferedWriter(path,
StandardOpenOption.CREATE,
StandardOpenOption.WRITE);
PrintWriter pw = new PrintWriter(bw)) {
for (String write : memory) {
pw.println(write);
}
}
catch (IOException e) {
e.printStackTrace();
}
}
public void createNote() {
String dateTime = getTimestamp();
System.out.println();
System.out.println("Enter a note");
System.out.print("> ");
String note = reader.nextLine();
memory.add(note + " / " + dateTime);
fileHandling();
System.out.println("Note is saved!");
}
public void searchNote() {
System.out.print("\nEnter note number: ");
try {
int search = reader.nextInt();
reader.nextLine();
System.out.println("\nSearch result:");
int index = memory.indexOf(memory.get(search - 1));
if (index != -1) {
System.out.println("[" + (index + 1) + "]" + " " + memory.get(search - 1));
}
else {
System.out.println("Note number-" + search + " is not found in the collection!");
}
}
catch (IndexOutOfBoundsException e) {
System.out.println("The note number you have entered is invalid!");
}
}
public void updateNote() {
String dateTime = getTimestamp(); // ZonedDateTime.now(ZoneId.systemDefault()).format(dateTimeObj);
System.out.print("\nEnter note number to change: ");
try {
int search = reader.nextInt();
int index = memory.indexOf(memory.get(search - 1));
String updateLine;
if (index != -1) {
System.out.println("\nCurrent note: ");
System.out.println("[" + (index + 1) + "]" + " " + memory.get(search - 1));
System.out.println("\nThe updated note will be: ");
System.out.print("> ");
reader.nextLine();
updateLine = reader.nextLine();
memory.set(index, updateLine + " /" + dateTime);
System.out.print("Note has been updated successfully!\n");
}
else {
System.out.println(search + " is not found in the collection!");
}
}
catch (IndexOutOfBoundsException e) {
System.out.println("The note number you have entered is invalid!");
}
fileHandling();
}
public void deleteNote() {
System.out.print("\nEnter note number to delete: ");
try {
int search = reader.nextInt();
reader.nextLine();
int index = memory.indexOf(memory.get(search - 1));
System.out.println();
if (index != -1) {
System.out.println("[" + (index + 1) + "]" + " " + memory.get(search - 1));
System.out.print("\nDo you want to delete this note? \n[y] or [n]: ");
char delDecision = reader.nextLine().charAt(0);
if (delDecision == 'y' || delDecision == 'Y') {
memory.remove(index);
System.out.println("Note has been deleted successfully!");
System.out.println();
}
else if (delDecision == 'n' || delDecision == 'N') {
System.out.println("Note was not deleted!");
}
else {
System.out.println("Invalid input!");
}
}
else {
System.out.println(search + " is not found in the collection!");
}
}
catch (IndexOutOfBoundsException e) {
System.out.println("The note number you have entered is invalid!");
}
fileHandling();
}
public void displayNote() {
if (memory.size() > 0) {
int counter = 0;
for (String note : memory) {
System.out.printf("%d. %s%n", ++counter, note);
}
}
else {
System.out.println("There are no notes.");
}
}
private String getTimestamp() {
LocalDate todayDate = LocalDate.now();
LocalTime nowTime = LocalTime.now();
String timeFormat = nowTime.format(DateTimeFormatter.ofLocalizedTime(FormatStyle.MEDIUM));
String dateTime = todayDate.toString() + " at " + timeFormat;// ZonedDateTime.now(ZoneId.systemDefault()).format(dateTimeObj);
return dateTime;
}
private void loadFile() throws IOException {
Path path = Paths.get(FILENAME);
if (Files.isRegularFile(path)) {
memory.addAll(Files.readAllLines(path, Charset.defaultCharset()));
}
}
private void showMenu() {
String choice = "";
while (!QUIT.equalsIgnoreCase(choice)) {
System.out.println(CREATE + " - Create note");
System.out.println(DELETE + " - Delete note");
System.out.println(FIND + " - Search notes");
System.out.println(SHOW + " - Show notes");
System.out.println(UPDATE + " - Update note");
System.out.println(QUIT + " - Quit");
System.out.println();
System.out.print("Your choice: ");
choice = reader.nextLine();
if (!choice.isEmpty()) {
choice = choice.substring(0, 1);
choice = choice.toUpperCase();
switch (choice) {
case CREATE -> createNote();
case DELETE -> deleteNote();
case FIND -> searchNote();
case SHOW -> displayNote();
case UPDATE -> updateNote();
case QUIT -> System.out.println("Good bye.");
default -> System.out.println("Invalid: " + choice);
}
}
else {
System.out.println("No selection entered. Retry.");
}
}
}
public static void main(String[] args) {
try {
FileSys fs = new FileSys();
fs.showMenu();
}
catch (IOException xIo) {
xIo.printStackTrace();
}
}
}
Your code does not initially load memory with contents of file notes.txt so I added that in the constructor. Consequently you don't need to append to the file since you simply overwrite it with contents of memory.
The file handling is done using NIO.2 including try-with-resources – which was added in Java 7. There are more NIO.2 examples in the JDK documentation.
Whenever the code throws an unexpected exception, it is nearly always a good idea to print the stack trace.

Read empty line in text file

if I want to read file from text file and store it in an array,each line goes to correct array
this is the text file
111111,34,24.5,first line
222222,53,22.0,second line
333333,,32.0,third line
44444,22,12.6,
if line is empty through exception saying "title is missing" or something like that.
a code has been made if the array length==4 then display lines in order but if length less than 4 and line is missing throw exception but when I want to put last array[3] gives me error. have a look if you can seethe error that would help
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class Itry {
public static void main(String[] args) {
// TODO Auto-generated method stub
String [] splitArray = new String[4];
String line = "";
String array1, description;
int number;
double price;
// Total sales
double total = 0;
Scanner keyboard = new Scanner (System.in);
// Allow the user to enter the name of text file that the data is stored in
System.out.println("This program will try to read data from a text file ");
System.out.print("Enter the file name: ");
String filename = keyboard.nextLine();
Scanner fileReader = null;
try {
File Fileobject = new File (filename);
fileReader = new Scanner (Fileobject);
System.out.println("\nTransactions");
System.out.println("================");
while(fileReader.hasNext())
{
// Contains stock code,Quantity,Price,Description
line = fileReader.nextLine();// Read a line of data from text file
splitArray = line.split(",");
// check to make sure there are 4 parts in splitArray
if(splitArray.length == 4)
{
// remove spaces
splitArray[0] = splitArray[0].trim();
splitArray[1] = splitArray[1].trim();
splitArray[2] = splitArray[2].trim();
splitArray[3] = splitArray[3].trim();
// Extract each item into an appropriate
// variable
try {
array1 = splitArray[0];
number = Integer.parseInt(splitArray[1]);
price = Double.parseDouble(splitArray[2]);
description = splitArray[3];
// Output item
System.out.println("Sold "+String.format("%-5d", number) +
String.format("%-12s", description )+ " at "+"£"+
String.format("%-5.2f", price));
// Compute total
total += number * price;
} // end of try
catch(NumberFormatException e)
{
System.out.println("Error: Cannot convert to number");
}
} //end of if
else if (splitArray[0].length()<1) {
try { splitArray[0] = splitArray[0].trim();
System.out.println(" Title is missing "+" "+splitArray[1] +""+splitArray[2]+"");
}
catch(NumberFormatException e)
{
System.out.println("Error: Cannot convert to number");
}
}
else if (splitArray[1].length()<=1) {
try { splitArray[1] = splitArray[1].trim();
System.out.println(splitArray[0]+" "+" here is missing " +""+splitArray[2] );
}
catch(NumberFormatException e)
{
System.out.println("Error: Cannot convert to number");
}}
else if (splitArray[2].length()<=1) {
try { splitArray[2] = splitArray[2].trim();
System.out.println(splitArray[0]+" "+splitArray[1] +""+" here is missing "+splitArray[3]);
}
catch(NumberFormatException e)
{
System.out.println("Error: Cannot convert to number");
}}
else if (splitArray[3].length()<=1) {
try { splitArray[3] = splitArray[3].trim();
System.out.println(splitArray[0]+" "+splitArray[1] +""+splitArray[2]+"title is missing");
}
catch(NumberFormatException e)
{
System.out.println("Error: Cannot convert to number");
}}
}//end of while
System.out.printf("\nTotal sales: £"+String.format("%-6.2f", total));
}// end of try block
catch (FileNotFoundException e)
{
System.out.println("Error - File does not exist");
}
}
}

You can do it as follows:
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
// TODO Auto-generated method stub
String[] splitArray = new String[4];
String line = "";
String array1, description;
int number;
double price;
// Total sales
double total = 0;
Scanner keyboard = new Scanner(System.in);
// Allow the user to enter the name of text file that the data is stored in
System.out.println("This program will try to read data from a text file ");
System.out.print("Enter the file name: ");
String filename = keyboard.nextLine();
Scanner fileReader = null;
try {
File Fileobject = new File(filename);
fileReader = new Scanner(Fileobject);
System.out.println("\nTransactions");
System.out.println("================");
int count = 1;
while (fileReader.hasNext()) {
// Contains stock code,Quantity,Price,Description
line = fileReader.nextLine();// Read a line of data from text file
try {
if (line != null && line.length() > 0) {
splitArray = line.split(",");
// check to make sure there are 4 parts in splitArray
if (splitArray.length == 4) {
// remove spaces
splitArray[0] = splitArray[0].trim();
splitArray[1] = splitArray[1].trim();
splitArray[2] = splitArray[2].trim();
splitArray[3] = splitArray[3].trim();
// Extract each item into an appropriate variable
try {
array1 = splitArray[0];
number = Integer.parseInt(splitArray[1]);
price = Double.parseDouble(splitArray[2]);
description = splitArray[3];
// Output item
System.out.println(
"Sold " + String.format("%-5d", number) + String.format("%-12s", description)
+ " at " + "£" + String.format("%-5.2f", price));
// Compute total
total += number * price;
} catch (NumberFormatException e) {
System.out.println("Error in line#" + count + ": insufficient/invalid data");
}
} else {
throw new IllegalArgumentException(
"Error in line#" + count + ": insufficient/invalid data");
}
} else {
throw new IllegalArgumentException("Line#" + count + " is empty");
}
} catch (IllegalArgumentException e) {
System.out.println(e.getMessage());
}
count++;
} // end of while
System.out.printf("\nTotal sales: £" + String.format("%-6.2f", total));
} catch (FileNotFoundException e) {
System.out.println("Error - File does not exist");
}
}
}
A sample run:
This program will try to read data from a text file
Enter the file name: data2.txt
Transactions
================
Sold 34 Apple at £24.50
Line#2 is empty
Sold 53 Mango at £22.00
Line#4 is empty
Error in line#5: insufficient/invalid data
Line#6 is empty
Error in line#7: insufficient/invalid data
Total sales: £1999.00
Content of data2.txt:
111111,34,24.5,Apple
222222,53,22.0,Mango
333333,,32.0,Orange
44444,22,12.6,

Retrieve saved data from a text file but only show a portion of the data Java JGrasp

I have programmed a game were I have made it so that you can save your score, if you have a good score you will be in the top 10. My problem is when I retrieve the data with the saved names, I only want a proportion of that data to be shown, in this case 10 names.
Here is my code.
public static void Highscore(List<Highscore> data) {
String HighscoreList = "";
try {
//Textfilens name
String filname = "Highscore.txt";
Scanner inFil = new Scanner(new File(filname));
while(inFil.hasNext()) {
String name = inFil.next();
String percent = inFil.next();
HighscoreLista += name + "\n" + percent + "%" + "\n\n";
} inFil.close();
} catch (FileNotFoundException e1) {
JOptionPane.showMessageDialog(null,"File was not found!");
}
JOptionPane.showMessageDialog(null, HighscoreList);
}//Highscore ends
How do I only show a proportion of the players in the final message (Highscorelist).
Thank you for helping.

Create a counter variable in the function to track the number of items in the while loop and check the counter variable along with the while condition
public static void Highscore(List<Highscore> data) {
String HighscoreList = "";
int counter =0;
try {
//Textfilens name
String filname = "Highscore.txt";
Scanner inFil = new Scanner(new File(filname));
while(inFil.hasNext() && counter<=10) {
counter++;
String name = inFil.next();
String percent = inFil.next();
HighscoreLista += name + "\n" + percent + "%" + "\n\n";
} inFil.close();
} catch (FileNotFoundException e1) {
JOptionPane.showMessageDialog(null,"File was not found!");
}
JOptionPane.showMessageDialog(null, HighscoreList);
}//Highscore ends

Java: How do I compare user input to columns in text file?

I'm pretty new to Java, so after several days of trying to figure out how to compare user input to a column in a text file, I am in desperate need of help. I want to be sure that an employee who punches-in has not punched-in once before without punching-out after that. In addition, I would like to be able to ensure that a user cannot punch-out of the system unless they have previously punched-in. I know that I have to split the lines in the text file in order to make them accessible separately, but I don't know how to compare them to user input. Any help is greatly appreciated! My code is as follows:
import java.text.*;
import java.util.*;
import java.io.*;
import java.nio.file.*;
public class TimeClockApp
{
// declare class variables
private static EmployeeDAO employeeDAO = null;
private static TimeClockDAO timeClockDAO = null;
private static Scanner sc = null;
// format date and time / //HH converts hour in 24 hours format (0-23), day calculation
private static DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
public static void main(String[] args) throws Exception
{
// set the class variables
employeeDAO = DAOFactory.getEmployeeDAO();
timeClockDAO = DAOFactory.getTimeClockDAO();
sc = new Scanner(System.in);
int employeeID = 0;
List<Employee> employees = employeeDAO.readEmployees();
List<TimeClock> timePunches = timeClockDAO.readTimePunches();
if(timePunches == null)
{
timePunches = new ArrayList<TimeClock>();
}
// display a welcome message
System.out.println("Welcome to the Punch-In/Punch-Out Screen\n");
// print option menu
System.out.print("Please choose an option below:" + "\n"
+ "I. Punch In" + "\n"
+ "O. Punch Out" + "\n");
String choice = "";
// get input from user
Scanner sc = new Scanner(System.in);
while(choice != null)
{
// get input from user "i" or "o"
while (!choice.equalsIgnoreCase("i") && !choice.equalsIgnoreCase("o"))
{
// it will not continue if user does not enter a valid choice
choice = Validator.getScreenChoice(sc, "Choice: ");
if(!choice.equalsIgnoreCase("i") && !choice.equalsIgnoreCase("o"))
{
System.out.println("Invalid choice. Please try again.");
}
}
System.out.println(); // print a blank line
if(!choice.isEmpty())
{
// create employee object
Employee employee = null;
System.out.println("PUNCH CLOCK");
System.out.println("-----------");
// read employee ID and compare to employee.txt
while(employee == null)
{
employeeID = Validator.getEmployeeID(sc,
"Enter Employee ID: ");
for(Employee e : employees)
{
if(e.getEmployeeID() == employeeID)
{
employee = e;
break;
}
}
}
// if employee ID is valid, have they punched in already?
// if not, try again.
// read timeclock.txt
timeClockDAO.readTimePunches();
if(employeeID == employee.getEmployeeID() && choice.equalsIgnoreCase("o")) // <-- This is where I'm having trouble
{
if(timePunches.contains("i"))
{
if(timePunches.contains(employeeID))
{
System.out.println("Employee " + employeeID + " has already punched in. Please try again.");
}
}
// has employee punched in? If yes, continue. <-- Beginning here, NetBeans ignores this whole deal
for(TimeClock t : timePunches)
{
if(t.getPunchInOrOut() && choice.equalsIgnoreCase("i"))
{
timePunches = t;
break;
}
}
// if employee has not punched in, try again
if(timePunches.contains("i"))
{
if(timePunches.contains(employeeID))
{
System.out.println("Employee " + employeeID + " has not punched in yet. Please try again.");
}
}
} // <-- NetBeans stops ignoring and continues from here
TimeClock newTimePunch = new TimeClock(employeeID, new Date(), choice);
// if employee ID is valid,
// addition of date and time to arraylist/text file
timePunches.add(newTimePunch);
//write to the file
timeClockDAO.writeTimePunch(newTimePunch);
// conditional statement for in/out + formatting
System.out.println("Punch-" + (choice.equalsIgnoreCase("i") ? "In" : "Out") + " Successful!" + "\n"
+ "Date & Time: " + dateFormat.format(new Date()) + "\n"
+ "Employee Name: " + employee.getFirstName() + " " + employee.getLastName() + "\n"
+ "Employee ID: " + employee.getEmployeeID() + "\n");
System.out.println(); // print a blank line
break;
}
else
{
System.out.println("Invalid entry. Please try again.");
}
}
// press enter to continue to the main screen
System.out.printf("Press enter to return to the main screen. ");
sc.nextLine();
System.out.println("Okay, returning to Main Screen. Goodbye!");
System.out.println(); // print a blank line
MainScreenApp.main(args);
}
}
Can I use the timeClockDAO.readTimePunches() portion of my code to read and compare columns in the text file to the user's input since the columns are already split there? The timeClockDAO.readTimePunches() method from the List<TimeClock> timePunches() list is as follows:
#Override
public List<TimeClock> readTimePunches()
{
if(timePunches != null)
return timePunches;
timePunches = new ArrayList<TimeClock>();
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
if(Files.exists(Paths.get(timeClockPath))) // prevent the FileNotFoundException
{
try(BufferedReader in = new BufferedReader(
new FileReader(
new File(timeClockPath))))
{
// read all employees in the file into the array list
String line = in.readLine();
while(line != null)
{
// split text file into columns
String[] columns = line.split(EmployeeTextFile.FIELD_SEP);
/*if(columns.length != 3)
{
System.err.println("Could not read text file for Time Punches.");
return null;
}*/
// employee ID column
int employeeID = Integer.parseInt(columns[0]);
// time stamp column
Date timeStamp;
try
{
timeStamp = dateFormat.parse(columns[1]);
}
catch (ParseException e)
{
System.err.println("Could not parse time stamp: " + columns[1]);
timeStamp = null;
}
// in or out column
String punchInOrOut = columns[2];
timePunches.add(new TimeClock(employeeID, timeStamp, punchInOrOut));
line = in.readLine();
}
}
catch(IOException e)
{
System.out.println(e);
return null;
}
}
return timePunches;
}
Thank you in advance!

The lines if(timePunches.contains("i")) and if(timePunches.contains(employeeID)) won't work since timePunches is an arrayList of TimeClock and unless you use a comparator or implement the Comparable interface, you cannot check if it contains a String value or an Employee value.
As I can assume in your code, you add timePunches to the end of the file so you only need to compare to the last item of your ArrayList to see if the current employee's state is punched in or punched out.
Instead of if(timePunches.contains("i")) and if(timePunches.contains(employeeID)) you should first fill your ArrayList only with your current Employee punches. Then, do something similar to:
if((timePunches.get(timePunches.size()).getPunchedInOrOut.equals("i") && choice.equals("o")) || (timePunches.get(timePunches.size()).getPunchedInOrOut.equals("o") && choice.equals("i"))...

Displaying Information Within Random Access File

I have created an application that allows the user to enter their account number, balance(no more than 99999), and last name. The program will take this information and insert it into a .txt file at a location corresponding to the account number(acct). Here is the code for that:
import java.io.*;
public class NationalBank {
public static void main(String[] args) throws Exception{
InputStreamReader temp = null;
BufferedReader input = null;
try {
temp = new InputStreamReader(System.in);
input = new BufferedReader(temp);
int acct;
double amount;
String name;
RandomAccessFile file = new RandomAccessFile("bank.txt", "rw");
while(true) {
// Asks for input
System.out.println("Enter Account Number (0-9999): ");
acct = Integer.parseInt(input.readLine());
System.out.println("Enter Last Name: ");
name = input.readLine();
System.out.println("Enter Balance ");
amount = Double.parseDouble(input.readLine());
// Making sure account numbers are between 0 and 9999
if(acct >=0 && acct <= 9999) {
file.seek(acct*17);
file.write(truncateName(name));
file.writeBytes(" " +amount);
}
else {
continue;
}
// Asks user if more entries are needed
System.out.println("Enter More? (y/n)");
if (input.readLine().toLowerCase().equals("n"))
break;
}
file.close();
}
catch (Exception e) {
}
}
// Truncate/adding spaces to name until 8 characters
public static byte[] truncateName (String name) {
byte[] result = new byte[8];
for (int i = 0; i < 8; i++)
result [i] = i < name.length () ? (byte)name.charAt (i) : (byte)' ';
return result;
}
}
Now, I am trying to make an application that will write back all of the accounts that have information within them(with last name and balance). I need to display the account number, balance, and last name of those accounts. So far, I have:
import java.io.*;
public class DisplayBank {
public static void main(String[] args) throws IOException {
FileInputStream input = new FileInputStream ("bank.txt");
try {
byte[] record = new byte[17];
while (input.read(record) == 17) {
String name = new String(record, 0, 8);
long bits = 0;
for (int i = 8; i < 17; i++) {
bits <<= 8;
bits |= record[i] & 0xFF;
}
double amount = Double.longBitsToDouble(bits);
System.out.println("Account Number: " + record + " Name: " + name + ", amount: " + amount);
}
}
catch (IOException e) {
}
finally {
input.close();
}
}
}
This currently displays only the name correctly. The balance is incorrect, and I don't know how to get the account number. In order to get the account number, I would need to get the position of name. In order to get the amount, I would need to seek name, offset 9 bytes, then read the next 8 bytes...

If you want to parse a text file that contains last names and amounts similar what you provided:
example provided
LastName 93942.12
What I would do is to try something like the following
public void read_file(){
try{
// Open the file that is the first
// command line parameter
FileInputStream fstream = new FileInputStream("C:\\Users\\Alos\\Desktop\\test.txt");
// Use DataInputStream to read binary NOT text.
BufferedReader br = new BufferedReader(new InputStreamReader(fstream));
String strLine;
int record = 0;
//Read File Line By Line
while ((strLine = br.readLine()) != null) {
String[] splits = strLine.split("\t");
String LastName = splits[0];
String Amount = splits[1];
System.out.println("Account Number: " + record + " Name: " + LastName + ", amount: " + Amount);
record++;
}
//Close the input stream
in.close();
}catch (Exception e){//Catch exception if any
System.err.println("Error: " + e.getMessage());
}
}
This might not be exactly what you're looking for but please take a look and update your question if you would like something different.

I it's not a homework, I would strongly recommend to use some RDBMS like Derby or MySQL.