How to get the capacity of ByteBuffer in java.

In this tutorial you will see how to get the capacity of ByteBuffer in java.

In this tutorial you will see how to get the capacity of ByteBuffer in java.

How to get the capacity of ByteBuffer in java.

In this tutorial, we will discuss how to get the capacity of buffer. The ByteBuffer
class is a container for handling data. The ByteBuffer class is available in java.nio package.

In this example, we will compute the capacity of buffer. The capacity() method returns
the capacity of buffer. The method allocate( int capacity) creates a new byte buffer. The
FileChannel class creates a channel for reading, and writing file. The FileChannel is similar
to the stream but they are few different. The channel can read write both, but stream can either
read-only or write-only. The getChannel method of FileInputStream class returns the
Channel associated with this file input stream. The read() method of FileChannel class
fills byte buffer created by using allocate() method.

About ByteBuffer API:

The java.nio.ByteBuffer class extends java.nio.Buffer class. It provides the following methods:

Return type	Method	Description
static ByteBuffer	allocate( int capacity)	The allocate() method create a byte buffer of specified capacity.
final int	capacity()	The capacity() method returns the capacity og associated buffer.

code


import java.io.*;

import java.nio.*;

import java.io.FileInputStream;

import java.nio.ByteBuffer;

import java.nio.channels.FileChannel;



public class ByteBufferCapacity {

  public static final int size = 1024;

    public static void main(String[] args) throws Exception {

    FileInputStream finStream = new FileInputStream(args[0]);

    System.out.println("Given file name :" + args[0]);

    FileChannel fchannel = finStream.getChannel();

    ByteBuffer bytebuf = ByteBuffer.allocate(size);

    fchannel.read(bytebuf);

    System.out.println("Capacity of ByteBuffer : "

+ bytebuf.capacity());

  }

}

Following is the output if you run the application:

C:\>java ByteBufferCapacity C:\Work\Bharat\load\ByteBuffercapicity\test.txt
Given file name :C:\Work\Bharat\load\ByteBuffercapicity\test.txt
Capacity of ByteBuffer : 1024

Download this code

Ads