With this example we are going to demonstrate how to read bytes from a ByteBuffer. Additionally we will show you several of ByteBuffer‘s API methods in order to share some light on how to randomly ready data from it.
package com.javacodegeeks.snippets.core;
import java.nio.ByteBuffer;
public class GetByteFromByteBuffer {
public static void main(String[] args) {
// Create a byte array
byte[] bytes = { 0x00, 0x01, 0x02, 0x03, 0x04};
// Wrap a byte array into a buffer
ByteBuffer buf = ByteBuffer.wrap(bytes);
// Get the buffer's capacity
int capacity = buf.capacity();
// Get the buffer's limit
int limit = buf.limit();
// Get the buffer's position
int position = buf.position();
System.out.println("Buffer capacity: " + capacity);
System.out.println("Buffer limit: " + limit);
System.out.println("Buffer position: " + position);
// Absolute get method. Reads byte at given index (does not affect the position)
byte b = buf.get(2);
System.out.println("byte: " + b);
// Set the position
buf.position(3);
// Relative get method. Reads byte at buffer's current position and increments position.
b = buf.get();
System.out.println("byte: " + b);
// Get remaining byte count
int remainingBytes = buf.remaining();
System.out.println("Buffer remaining bytes: " + remainingBytes);
// Rewinds this buffer. The position is set to zero and the mark is discarded
buf.rewind();
remainingBytes = buf.remaining();
System.out.println("Buffer remaining bytes: " + remainingBytes);
b = buf.get();
System.out.println("byte: " + b);
}
}
Output:
Buffer capacity: 5
Buffer limit: 5
Buffer position: 0
byte: 2
byte: 3
Buffer remaining bytes: 1
Buffer remaining bytes: 5
byte: 0
This was an example of how to read bytes from a ByteBuffer in Java.
