Java MIDI - ControllerEventListener (如何更换乐器)

import javax.sound.midi.*;

public class ChangeInstrumentExample implements ControllerEventListener {
    public static void main(String[] args) {
        try {
            Synthesizer synthesizer = MidiSystem.getSynthesizer();
            synthesizer.open();

            Receiver receiver = synthesizer.getReceiver();

            // 注册ControllerEventListener，监听控制器事件
            synthesizer.getTransmitter().setReceiver(receiver);
            synthesizer.getTransmitter().setReceiver(receiver);

            // 控制器号码用于区分不同的MIDI控制器，如音量、音调、乐器等
            int controllerNumber = 7; // 控制器号码为7表示乐器选择

            ShortMessage controlChange = new ShortMessage();
            // 设置控制器消息类型和控制器号码
            controlChange.setMessage(ShortMessage.CONTROL_CHANGE, 0, controllerNumber);

            // 发送控制器消息，触发ControllerEventListener的回调方法
            receiver.send(controlChange, -1);

            // 关闭音源
            synthesizer.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    public void controlChange(ShortMessage event) {
        // MIDI控制器事件回调方法的实现
        int controllerNumber = event.getData1(); // 获取控制器号码
        int controllerValue = event.getData2(); // 获取控制器值

        if (controllerNumber == 7) {
            // 根据控制器值更换乐器
            System.out.println("Changing instrument to " + controllerValue);
        }
    }
}