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Java DataInputStream readByte() Method with Example

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

DataInputStream Class readByte() method

• readByte() method is available in java.io package.
• readByte() method is used to read and return a signed input byte value.
• readByte() 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.
• readByte() method may throw an exception at the time of reading byte.
  • 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 byte readByte();

Parameter(s):

• It does not accept any parameter.

Return value:

The return type of the method is byte, it returns the signed byte value read.

Example:

// Java program to demonstrate the example 
// of byte readByte() method of 
// DataInputStream

import java.io.*;

public class ReadByteOfDataInputStream {
 public static void main(String[] args) throws Exception {
  InputStream is_stm = null;
  DataInputStream dis_stm = null;

  byte[] b_arr = {
   97,
   0,
   99,
   100,
   0,
   101
  };

  try {
   // Instantiate ByteArrayInputStream and 
   // DataInputStream
   is_stm = new ByteArrayInputStream(b_arr);
   dis_stm = new DataInputStream(is_stm);

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

    // By using readByte() method isto read one
    // byte at a time
    byte val = dis_stm.readByte();
    System.out.println("dis_stm.readByte(): " + val);
   }
  } catch (Exception ex) {
   System.out.println(ex.toString());
  } finally {
   // To free system resorces linked
   // with these streams
   if (is_stm != null)
    is_stm.close();

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

Output

dis_stm.readByte(): 97
dis_stm.readByte(): 0
dis_stm.readByte(): 99
dis_stm.readByte(): 100
dis_stm.readByte(): 0
dis_stm.readByte(): 101