I have a text file, formatted as follows:
Han Solo:1000
Harry:100
Ron:10
Yoda:0
I need to make an arrayList of objects which store the player's name (Han Solo) and their score (1000) as attributes. I would like to be able to make this arrayList by reading the file line by line and splitting the string in order to get the desired attributes.
I tried using a Scanner object, but didn't get far. Any help on this would be greatly appreciated, thanks.
You can create a Class call player. playerName and score will be the attributes.
public class Player {
private String playerName;
private String score;
// getters and setters
}
Then you can create a List
List<Player> playerList=new ArrayList<>();
Now you can try to do your task.
Additionally, you can read from file and split each line by : and put first part as playerName and second part as score.
List<Player> list=new ArrayList<>();
while (scanner.hasNextLine()){
String line=scanner.nextLine();
Player player=new Player();
player.setPlayerName(line.split(":")[0]);
player.setScore(line.split(":")[1]);
list.add(player);
}
You can have a Player class like this:-
class Player { // Class which holds the player data
private String name;
private int score;
public Player(String name, int score) {
this.name = name;
this.score = score;
}
// Getters & Setters
// Overrride toString() - I did this. Its optional though.
}
and you can parse your file which contains the data like this:-
List<Player> players = new ArrayList<Player>();
try {
BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream("input.txt"))); // I used BufferedReader instead of a Scanner
String line = null;
while ((line = br.readLine()) != null) {
String[] values = line.split(":"); // Split on ":"
players.add(new Player(values[0], Integer.parseInt(values[1]))); // Create a new Player object with the values extract and add it to the list
}
} catch (IOException ioe) {
// Exception Handling
}
System.out.println(players); // Just printing the list. toString() method of Player class is called.
If you have Object:
public class User
{
private String name;
private int score;
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
public int getScore()
{
return score;
}
public void setScore(int score)
{
this.score = score;
}
}
Make an Reader class that reads from the file :
public class Reader
{
public static void main(String[] args)
{
List<User> list = new ArrayList<User>();
File file = new File("test.txt");
BufferedReader reader = null;
try
{
reader = new BufferedReader(new FileReader(file));
String line;
while ((line = reader.readLine()) != null)
{
String[] splitedString = line.split(":");
User user = new User();
user.setName(splitedString[0]);
user.setScore(Integer.parseInt(splitedString[1]));
list.add(user);
}
}
catch (IOException e)
{
e.printStackTrace();
}
finally
{
if (reader != null)
{
try
{
reader.close();
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
for (User user : list)
{
System.out.println(user.getName()+" "+user.getScore());
}
}
}
The output will be :
Han Solo 1000 Harry 100 Ron 10 Yoda 0
Let's assume you have a class called Player that comprises two data members - name of type String and score of type int.
List<Player> players=new ArrayList<Player>();
BufferedReader br=null;
try{
br=new BufferedReader(new FileReader("filename"));
String record;
String arr[];
while((record=br.readLine())!=null){
arr=record.split(":");
//Player instantiated through two-argument constructor
players.add(new Player(arr[0], Integer.parseInt(arr[1])));
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
finally{
if(br!=null)
try {
br.close();
} catch (IOException e1) {
e1.printStackTrace();
}
}
For small files (less than 8kb), you can use this
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;
public class NameScoreReader {
List<Player> readFile(final String fileName) throws IOException
{
final List<Player> retval = new ArrayList<Player>();
final Path path = Paths.get(fileName);
final List<String> source = Files.readAllLines(path, StandardCharsets.UTF_8);
for (final String line : source) {
final String[] array = line.split(":");
if (array.length == 2) {
retval.add(new Player(array[0], Integer.parseInt(array[1])));
} else {
System.out.println("Invalid format: " + array);
}
}
return retval;
}
class Player {
protected Player(final String pName, final int pScore) {
super();
this.name = pName;
this.score = pScore;
}
private String name;
private int score;
public String getName()
{
return this.name;
}
public void setName(final String name)
{
this.name = name;
}
public int getScore()
{
return this.score;
}
public void setScore(final int score)
{
this.score = score;
}
}
}
Read the file and convert it to string and split function you can apply for the result.
public static String getStringFromFile(String fileName) {
BufferedReader reader;
String str = "";
try {
reader = new BufferedReader(new FileReader(fileName));
String line = null;
StringBuilder stringBuilder = new StringBuilder();
while ((line = reader.readLine()) != null) {
stringBuilder.append(line);
stringBuilder.append("\n");
}
str = stringBuilder.toString();
} catch (IOException e) {
e.printStackTrace();
}
return str;
}
public static void main(String[] args) {
String stringFromText = getStringFromFile("C:/DBMT/data.txt");
//Split and other logic goes here
}
