ByteBufferTest

ByteBufferTest.java

import static org.junit.Assert.*;

import java.nio.ByteBuffer;

import org.junit.Test;

public class ByteBufferTest {

    @Test
    public void test1() {

        ByteBuffer bf = ByteBuffer.allocate(1024);

        bf.putInt(1);
        bf.put("123".getBytes());
        bf.put((byte) 0);
        bf.putInt(2);

        bf.flip();

        assertEquals(1, bf.getInt());
        byte[] result = new byte["123".getBytes().length];
        bf.get(result);
        assertArrayEquals("123".getBytes(), result);

        assertEquals((byte) 0, bf.get());


        // int 2 is remain in the buffer
        assertTrue(bf.hasRemaining());
        bf=bf.compact();
        assertEquals(Integer.BYTES,bf.position());

        bf.flip();
        assertEquals(0,bf.position());
        assertTrue(bf.hasRemaining());

        //read 2
        assertEquals(2,bf.getInt());
        assertFalse(bf.hasRemaining());
        bf.clear();

    }

    @Test
    public void test2() {

        ByteBuffer bf = ByteBuffer.allocate(1024);

        bf.putInt(1);
        bf.put("123".getBytes());
        bf.put((byte) 0);
        bf.putInt(2);


        bf.flip();

        assertEquals(1, bf.getInt());
        byte[] result = new byte["123".getBytes().length];
        bf.get(result);
        assertArrayEquals("123".getBytes(), result);

        assertEquals((byte) 0, bf.get());

        //rewind position to 0;
        bf.rewind();

        assertEquals(1, bf.getInt());
        result = new byte["123".getBytes().length];
        bf.get(result);
        assertArrayEquals("123".getBytes(), result);

        assertEquals((byte) 0, bf.get());


        assertEquals(2,bf.getInt());
    }


    @Test
    public void test3() {

        ByteBuffer bf = ByteBuffer.allocate(1024);

        bf.putInt(1);
        bf.put("123".getBytes());
        bf.put((byte) 0);
        bf.putInt(2);

        bf.flip();

        assertEquals(1, bf.getInt());
        byte[] result = new byte["123".getBytes().length];
        bf.get(result);
        assertArrayEquals("123".getBytes(), result);

        assertEquals((byte) 0, bf.get());

        bf.mark();


        assertEquals(2,bf.getInt());

        bf.reset();

        assertEquals(2,bf.getInt());
    }
}