DataInputStream Class in Java

Java DataInputStream class allows an application to read primitive data from the input stream in a machine-independent way. Java application generally uses the data output stream to write data that can later be read by a data input stream.

DataInputStream class Constructor

  • DataInputStream(InputStream in) - Creates a DataInputStream that uses the specified underlying InputStream.

DataInputStream class Methods

  • int read(byte[] b) - Reads some number of bytes from the contained input stream and stores them into the buffer array b.
  • int read(byte[] b, int off, int len) - Reads up to len bytes of data from the contained input stream into an array of bytes.
  • boolean readBoolean() - See the general contract of the readBoolean method of DataInput.
  • byte readByte() - See the general contract of the readByte method of DataInput.
  • char readChar() - See the general contract of the readChar method of DataInput.
  • double readDouble() - See the general contract of the readDouble method of DataInput.
  • float readFloat() - See the general contract of the readFloat method of DataInput.
  • void readFully(byte[] b) - See the general contract of the readFully method of DataInput.
  • void readFully(byte[] b, int off, int len) - See the general contract of the readFully method of DataInput.
  • int readInt() - See the general contract of the readInt method of DataInput.
  • long readLong() - See the general contract of the readLong method of DataInput.
  • short readShort() - See the general contract of the readShort method of DataInput.
  • int readUnsignedByte() - See the general contract of the readUnsignedByte method of DataInput.
  • int readUnsignedShort() - See the general contract of the readUnsignedShort method of DataInput.
  • String readUTF() - See the general contract of the readUTF method of DataInput.
  • static String readUTF(DataInput in) - Reads from the stream in a representation of a Unicode character string encoded in modified UTF-8 format; this string of characters is then returned as a String.
  • int skipBytes(int n) - See the general contract of the skipBytes method of DataInput.

DataInputStream class Example

A program to read each primitive char type from file sample.txt.
import java.io.DataInputStream;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

public class DataInputStreamExample {
 public static void main(String[] args) {
  try(InputStream input = new FileInputStream("sample.txt");  
     DataInputStream inst = new DataInputStream(input);){  
     int count = input.available(); 
     
     byte[] ary = new byte[count];  
     inst.read(ary);  
     for (byte bt : ary) {  
       char k = (char) bt;  
       System.out.print(k+"-");  
     }  
  } catch (IOException e) {
   e.printStackTrace();
  }
 }
}
Output:
T-h-e-r-e- -i-s- -s-o-m-e- -c-o-n-t-e-n-t- -i-n- -f-i-l-e- -
-n-e-w-l-i-n-e- -a-d-d-e-d- -t-o- -e-x-i-s-t-i-n-g- -f-i-l-e-
-

Reference

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