Read data from a text file using Java

Question

I need to read a text file line by line using Java. I use available() method of FileInputStream to check and loop over the file. But while reading, the loop terminates after the line before the last one. i.e., if the file has 10 lines, the loop reads only the first 9 lines. Snippet used :

while(fis.available() > 0)
{
    char c = (char)fis.read();
    .....
    .....
}

Answer 1

You should not use available(). It gives no guarantees what so ever. From the API docs of available():

Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next invocation of a method for this input stream.

You would probably want to use something like

try {
    BufferedReader in = new BufferedReader(new FileReader("infilename"));
    String str;
    while ((str = in.readLine()) != null)
        process(str);
    in.close();
} catch (IOException e) {
}

(taken from http://www.exampledepot.com/egs/java.io/ReadLinesFromFile.html)

Answer 2

How about using Scanner? I think using Scanner is easier

     private static void readFile(String fileName) {
       try {
         File file = new File(fileName);
         Scanner scanner = new Scanner(file);
         while (scanner.hasNextLine()) {
           System.out.println(scanner.nextLine());
         }
         scanner.close();
       } catch (FileNotFoundException e) {
         e.printStackTrace();
       }
     }

Read more about Java IO here

Answer 3

//The way that I read integer numbers from a file is...

import java.util.*;
import java.io.*;

public class Practice
{
    public static void main(String [] args) throws IOException
    {
        Scanner input = new Scanner(new File("cards.txt"));

        int times = input.nextInt();

        for(int i = 0; i < times; i++)
        {
            int numbersFromFile = input.nextInt();
            System.out.println(numbersFromFile);
        }




    }
}