How to write a java program that writes a MIDI file

Here is a very short java program that writes a midi file that will play on any modern MIDI player including most computer sound cards. This is not intended as a tutorial on the MIDI spec, nor the javax.sound.midi package, but rather as a simple demo of how it's done.

/**
 * midifile.java
 *
 * A very short program which builds and writes
 * a one-note Midi file.
 *
 * author  Karl Brown
 * last updated 2/24/2003
 */

import java.io.*;
import java.util.*;
import javax.sound.midi.*; // package for all midi classes
public class midifile
{
  public static void main(String argv[]) {
    System.out.println("midifile begin ");
	try
	{
//****  Create a new MIDI sequence with 24 ticks per beat  ****
		Sequence s = new Sequence(javax.sound.midi.Sequence.PPQ,24);

//****  Obtain a MIDI track from the sequence  ****
		Track t = s.createTrack();

//****  General MIDI sysex -- turn on General MIDI sound set  ****
		byte[] b = {(byte)0xF0, 0x7E, 0x7F, 0x09, 0x01, (byte)0xF7};
		SysexMessage sm = new SysexMessage();
		sm.setMessage(b, 6);
		MidiEvent me = new MidiEvent(sm,(long)0);
		t.add(me);

//****  set tempo (meta event)  ****
		MetaMessage mt = new MetaMessage();
        byte[] bt = {0x02, (byte)0x00, 0x00};
		mt.setMessage(0x51 ,bt, 3);
		me = new MidiEvent(mt,(long)0);
		t.add(me);

//****  set track name (meta event)  ****
		mt = new MetaMessage();
		String TrackName = new String("midifile track");
		mt.setMessage(0x03 ,TrackName.getBytes(), TrackName.length());
		me = new MidiEvent(mt,(long)0);
		t.add(me);

//****  set omni on  ****
		ShortMessage mm = new ShortMessage();
		mm.setMessage(0xB0, 0x7D,0x00);
		me = new MidiEvent(mm,(long)0);
		t.add(me);

//****  set poly on  ****
		mm = new ShortMessage();
		mm.setMessage(0xB0, 0x7F,0x00);
		me = new MidiEvent(mm,(long)0);
		t.add(me);

//****  set instrument to Piano  ****
		mm = new ShortMessage();
		mm.setMessage(0xC0, 0x00, 0x00);
		me = new MidiEvent(mm,(long)0);
		t.add(me);

//****  note on - middle C  ****
		mm = new ShortMessage();
		mm.setMessage(0x90,0x3C,0x60);
		me = new MidiEvent(mm,(long)1);
		t.add(me);

//****  note off - middle C - 120 ticks later  ****
		mm = new ShortMessage();
		mm.setMessage(0x80,0x3C,0x40);
		me = new MidiEvent(mm,(long)121);
		t.add(me);

//****  set end of track (meta event) 19 ticks later  ****
		mt = new MetaMessage();
        byte[] bet = {}; // empty array
		mt.setMessage(0x2F,bet,0);
		me = new MidiEvent(mt, (long)140);
		t.add(me);

//****  write the MIDI sequence to a MIDI file  ****
		File f = new File("midifile.mid");
		MidiSystem.write(s,1,f);
	} //try
		catch(Exception e)
	{
		System.out.println("Exception caught " + e.toString());
	} //catch
    System.out.println("midifile end ");
  } //main
} //midifile

midifile.mid - the MIDI file created by this program

midifile.java - the java source file

midifile.class - the java class file

Karl Brown MIDI servlet programming home page