Binary File
For Creating/Storing Information into the file
FileOutputStream fout = new FileOutputStream(new File("filename",true)); //true for append
DataOutputStream ffout = new DataOutputStream(fout);
Functions to store data:
Integers - ffout.writeInt();
Floating - ffout.writeFloat();
Double - ffout.writeDouble();
char - ffout.writeChar();
String - ffout.writeUTF();
For reading the file
FileInputStream fin = new FileInputStream(new File("filename"));
DataInputStream ffin = new DataInputStream(fin);
Functions to read data:
Integers - ffin.readInt();
Floating - ffin.readFloat();
Double - ffin.readDouble();
char - ffin.writeChar();
String - ffin.writeUTF();
Example: WAP a program to store 10 names and in a binary file and read the data
import java.util.*;
import java.io.*;
class demo
{
public static void main(String args[])throws IOException
{
FileOutputStream fout = new FileOutputStream(new File("STUDENT.DAT"),true); //true for append
DataOutputStream ffout = new DataOutputStream(fout);
Scanner sc = new Scanner(System.in);
for(int i=0;i<10;i++)
{
System.out.println("Enter the name: ");
String name = sc.next();
System.out.println("Enter roll: ");
int roll = sc.nextInt();
ffout.writeUTF(name);
ffout.writeInt(roll);
}
ffout.close();
fout.close();
FileInputStream fin = new FileInputStream(new File("STUDENT.DAT"));
DataInputStream ffin = new DataInputStream(fin);
boolean eof=false;
try
{
while(!eof)
{
String name = ffin.readUTF();
int roll = ffin.readInt();
System.out.println("Name: "+name);
System.out.println("Roll: "+roll);
}
}catch(Exception e)
{
eof=true;
System.out.println("File reading complete");
}
ffin.close();
fin.close();
sc.close();
}
}
Text File
---------------
For creating/storing data into file
------------------------------------
FileWriter fw = new FileWriter("filename",true); //append
BufferedWriter bw = new BufferedWriter(fw);
PrintWriter pw = new PrintWriter(bw);
Function to data into file
--------------------------
pw.println()
For reading data
-----------------
Scanner read = new Scanner(new File("filename"));
while(read.hasNext())
{
String name = read.next();
int roll = read.nextInt();
}
Example: WAP to accept 5 names and roll in a text file. Read the text and display the items.
import java.util.*;
import java.io.*;
class demo
{
public static void main(String args[])throws IOException
{
Scanner sc = new Scanner(System.in);
FileWriter fw = new FileWriter("students.txt",true); //append
BufferedWriter bw = new BufferedWriter(fw);
PrintWriter pw = new PrintWriter(bw);
String name;
int roll;
for(int i=0;i<2;i++)
{
System.out.println("Enter name: ");
name = sc.next();
System.out.println("Enter roll: ");
roll = sc.nextInt();
pw.println(name);
pw.println(roll);
}
pw.close();
bw.close();
fw.close();
sc.close();
Scanner read = new Scanner(new File("students.txt"));
System.out.println("Name\t\tRoll");
while(read.hasNext())
{
name = read.next();
roll = read.nextInt();
System.out.println(name+"\t\t"+roll);
}
read.close();
}
}