Storing file in java using arraylist

Question

I am reading a file and want to save it in an array list to be able to call this method in another class for later use. Here's my code:

    package com.qmul.rfid.reader;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;

public class ReadFile {

        public static void main(String[] args) {

            ArrayList<ReadFile> fileList = new ArrayList<ReadFile> ();

            try (BufferedReader br = new BufferedReader(new FileReader("C:\\tagNo.txt")))
            {

                String CurrentLine;

                while ((CurrentLine = br.readLine()) != null) {
                    System.out.println(CurrentLine);


                    fileList.add(CurrentLine);

                }

            } catch (IOException e) {
                e.printStackTrace();
            } 

        }
    }

I get an error at fileList.add(CurrentLine);. I know this is because CurrentLine does not match with ReadFile.

How can I make this work?

Thank you.

filelist is an array of readfiles, while currentline is a string. so i guess you have to create a new readfile object from a string. this obvioulsy depends on how the readfile is written in the file... — Leo
– Leo, Commented Feb 18, 2014 at 11:33

Marco13 · Accepted Answer · 2014-02-18 11:27:59Z

3

The parameters in the < ... > brackets specify the type of the elements stored in the list. In this case, you want to store String objects. So it should be

ArrayList<String> fileList = new ArrayList<String> ();

answered Feb 18, 2014 at 11:27

Marco13

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1 Comment

Agostino Over a year ago

If you are using Java 7, then you can spare some typing and use the diamond inference, ArrayList<String> fileList = new ArrayList<> ();

AnatolyG · Accepted Answer · 2014-02-18 12:39:08Z

1

You could replace

ArrayList <ReadFile> fileList = new ArrayList<ReadFile> ();

by

List<String> fileList = new ArrayList<>();

in JDK 7 style

answered Feb 18, 2014 at 12:39

AnatolyG

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Comments

Lukas Eichler · Accepted Answer · 2014-02-18 11:28:25Z

0

You declared an arraylist that stores ReadFile but you want to add a String to the list which causes this exception. Create another List from type List<String> and store the file content there.

answered Feb 18, 2014 at 11:28

Lukas Eichler

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Marco13 · Accepted Answer · 2014-02-18 11:28:25Z

0

Try ArrayList<String> fileList instead of ArrayList<ReadFile>

edited Feb 18, 2014 at 11:28

Marco13

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answered Feb 18, 2014 at 11:27

omgBob

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Marco Bolis · Accepted Answer · 2014-02-18 11:28:32Z

0

Type of CurrentLine is String, fileList should be:

ArrayList<String> fileList = new ArrayList<String>();

answered Feb 18, 2014 at 11:28

Marco Bolis

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Adarsh · Accepted Answer · 2014-02-18 11:29:34Z

0

Your arrayList is of type ReadFile. So it expects you to add elements of type ReadFile. What you need is change it to String.

 ArrayList<ReadFile> fileList = new ArrayList<ReadFile> ();

to

 ArrayList<String> fileList = new ArrayList<String> ();

answered Feb 18, 2014 at 11:29

Adarsh

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Sajan Chandran · Accepted Answer · 2014-02-18 11:30:13Z

0

Your ArrayList can hold objects of type ReadFile only, since you declared your ArrayList using <ReadLine>

 Change your ReadFile class to something like 

Class ReadFile {

  String line;
  ReadFile(String currentLine){
     this.line = currentLine;
  }
}

Then you can do

fileList.add(new ReadFile(CurrentLine));

answered Feb 18, 2014 at 11:30

Sajan Chandran

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Comments

user3135746 · Accepted Answer · 2014-02-18 11:46:54Z

0

You have to provide String instead of readfile. because here your list is expecting readfile.

ArrayList list = new ArrayList();

answered Feb 18, 2014 at 11:46

user3135746

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