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Java DataInputStream class

A data input stream lets an application machine-independent way to read primitive Java data types from an underlying input stream.

The following constructor is used to create a data input stream object. 

DataInputStream dis = DataInputStream(InputStream in);

Another way to create is to receive a byte array, and two integer variable off, len, off represents the first byte read, len indicates the length of bytes read.

No. Method Description
1 public final int read (byte [] r, int off, int len) throws IOException
Input stream contains from len bytes read into a byte array. If len is -1, it returns the number of bytes read.
2 Public final int read (byte [] b) throws IOException
Read some number of bytes from the input stream contains and stores them into the buffer array b in.
3
  1. public final Boolean readBooolean () throws IOException ,
  2. public final byte readByte () throws IOException ,
  3. public final short readShort () throws IOException
  4. public final Int readInt () throws IOException
Read a byte from the input stream, the input stream is returned as the corresponding basic data type of the return value of the two bytes.
4 public String readLine () throws IOException
Reads the next line of text from the input stream.

Examples

The following example illustrates the DataInputStream and DataOutputStream use this example to read from a text file test.txt 5 lines in and converted to uppercase letters, the last saved in another file test1.txt in. 

import java.io.*;

public class Test{
   public static void main(String args[])throws IOException{

      DataInputStream d = new DataInputStream(new
                               FileInputStream("test.txt"));

      DataOutputStream out = new DataOutputStream(new
                               FileOutputStream("test1.txt"));

      String count;
      while((count = d.readLine()) != null){
          String u = count.toUpperCase();
          System.out.println(u);
          out.writeBytes(u + "  ,");
      }
      d.close();
      out.close();
   }
}

The above examples compiled results are as follows: 

THIS IS TEST 1  ,
THIS IS TEST 2  ,
THIS IS TEST 3  ,
THIS IS TEST 4  ,
THIS IS TEST 5  ,