Home » Java programming language

Java DataInputStream readInt() Method with Example

DataInputStream Class readInt() method: Here, we are going to learn about the readInt() method of DataInputStream Class with its syntax and example.
Submitted by Preeti Jain, on March 30, 2020

DataInputStream Class readInt() method

• readInt() method is available in java.io package.
• readInt() method is used to read 4 bytes (i.e. 32 bit) of the int value of data input and returns an integer value read.
• readInt() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
• readInt() method may throw an exception at the time of reading int.
  • IOException: This exception may throw when this stream is not opened.
  • EndOfFileException: This exception may throw when this stream has reached its endpoint.

Syntax:

    public final void readInt();

Parameter(s):

• It does not accept any parameter.

Return value:

The return type of the method is void, it returns nothing.

Example:

// Java program to demonstrate the example 
// of void readInt() method of 
// DataInputStream

import java.io.*;

public class ReadIntOfDIS {
 public static void main(String[] args) throws IOException {
  InputStream is_stm = null;
  DataInputStream dis_stm = null;
  FileOutputStream fos_stm = null;
  DataOutputStream dos_stm = null;
  int[] i_arr = {
   100,
   200,
   300,
   400,
   500
  };

  try {
   // Instantiate FileInputStream, 
   // DataInputStream, FileOutputStream
   // and DataOutputStream 

   fos_stm = new FileOutputStream("C:\\Users\\Preeti Jain\\Desktop\\programs\\includehelp.txt");
   dos_stm = new DataOutputStream(fos_stm);

   // Loop to write each int till end
   for (int val: i_arr) {

    // By using writeInt() method isto
    // write an integer to the
    // DataOutputStream dos_stm

    dos_stm.writeInt(val);
   }

   is_stm = new FileInputStream("C:\\Users\\Preeti Jain\\Desktop\\programs\\includehelp.txt");
   dis_stm = new DataInputStream(is_stm);

   // Loop To Read Available Data till end
   while (dis_stm.available() > 0) {

    // By using readInt() method isto read 
    // integer at a time from dis_stm

    int in = dis_stm.readInt();
    System.out.println("dis_stm.readInt(): " + in );
   }
  } catch (Exception ex) {
   System.out.println(ex.toString());
  } finally {
   // To free system resources linked
   // with these streams
   if (is_stm != null)
    is_stm.close();

   if (dis_stm != null)
    dis_stm.close();

   if (dos_stm != null)
    dos_stm.close();

   if (fos_stm != null)
    fos_stm.close();
  }
 }
}

Output

dis_stm.readInt(): 100
dis_stm.readInt(): 200
dis_stm.readInt(): 300
dis_stm.readInt(): 400
dis_stm.readInt(): 500