Read long from file using DataInputStream : DataInputStream « File « Java Tutorial

1. Java Tutorial
2. File
3. DataInputStream

import java.io.DataInputStream;
import java.io.FileInputStream;

public class Main {

  public static void main(String[] args) throws Exception {
    FileInputStream fin = new FileInputStream("C:/Long.txt");
    DataInputStream din = new DataInputStream(fin);
    long l = din.readLong();
    System.out.println("long : " + l);
    din.close();
  }
}