In java, basic input-output stream provides a method for reading & writing bytes or character in a file. If we want to read-write primitive data typa(such as int , float etc.) than we can use filter classes to filter data in the original stream.
DataInputStream & DataOutputStream are two filter classes used for creating “data streams” for handling primitive data type.
Example: Write a program to write & read a primitive data on a same file.
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 |
import java.io.*; public class PrimitiveReadWrite { public static void main(String args[]) throws IOException { FileOutputStream o = new FileOutputStream("A.txt"); //Open file “A” for write DataOutputStream O = new DataOutputStream(o); //write primitive data on file A O.writeInt(1999); O.writeDouble(333.89); O.writeBoolean(false); O.writeChar('X'); O.close(); o.close(); //read primitive data from file A FileInputStream i = new FileInputStream("A.txt"); //open file A for read DataInputStream I = new DataInputStream(i); System.out.println(I.readInt()); System.out.println(I.readDouble()); System.out.println(I.readBoolean()); System.out.println(I.readChar()); I.close(); i.close(); } } |
|
1 2 3 4 5 |
Output: 1999 333.89 false X |