Question

我正在尝试创建一个可以播放MIDI键盘音符的程序。我无法让整个程序工作，但我现在正在尝试创建一个较小的概念证明程序来尝试并解决它。

为此，我试图将.mid文件播放到键盘（卡西欧CTK-3000），MidiPlay可以播放键盘。问题是，当我尝试在我的程序中弹奏键盘时，它什么也没玩。我的代码如下：

public class midiOut {

    public static void main(String[] args) throws IOException, MidiUnavailableException, InvalidMidiDataException
    {

        while(true) {
            //List Midi Devices
            MidiDevice.Info[] midiInfo = MidiSystem.getMidiDeviceInfo();
            int i = 0;
            for (MidiDevice.Info info : midiInfo) {
                System.out.println(i + ": " +info.getName());
                i+=1;
            }
            //Select Device
            Scanner in = new Scanner(System.in);
            int input = in.nextInt();

            if(input == -1)
            {
                break;
            }
            //Get Device and Open it
            MidiDevice selectedDevice = MidiSystem.getMidiDevice(midiInfo[input]);
            System.out.println(selectedDevice.getDeviceInfo().getName());
            selectedDevice.open();
            //Get Sequencer and Receiver, load the File and start playing
            Receiver receiver = selectedDevice.getReceiver();
            Sequencer sequencer = MidiSystem.getSequencer();
            sequencer.getTransmitter().setReceiver(receiver);
            sequencer.open();
            sequencer.setSequence(MidiSystem.getSequence(new File("C:\\Users\\Harris Mirza\\Downloads\\PennyLane.mid")));
            sequencer.start();

            selectedDevice.close();

        }
    }
}

Answer 1

意识到我的错误，我太早关闭了设备，在关闭前添加了一张支票，修改了代码：

import javax.sound.midi.*;
import java.io.File;
import java.io.IOException;
import java.util.Scanner;

public class midiOut {

    public static void main(String[] args) throws IOException, MidiUnavailableException, InvalidMidiDataException
    {

        while(true) {
            //List Midi Devices
            MidiDevice.Info[] midiInfo = MidiSystem.getMidiDeviceInfo();
            int i = 0;
            for (MidiDevice.Info info : midiInfo) {
                System.out.println(i + ": " +info.getName());
                i+=1;
            }
            //Select Device
            Scanner in = new Scanner(System.in);
            int input = in.nextInt();

            if(input == -1)
            {
                break;
            }
            //Get Device and Open it
            MidiDevice selectedDevice = MidiSystem.getMidiDevice(midiInfo[input]);
            System.out.println(selectedDevice.getDeviceInfo().getName());
            selectedDevice.open();
            //Get Sequencer and Receiver, load the File and start playing
            Receiver receiver = selectedDevice.getReceiver();
            Sequencer sequencer = MidiSystem.getSequencer();
            sequencer.getTransmitter().setReceiver(receiver);
            sequencer.open();
            sequencer.setSequence(MidiSystem.getSequence(new File("C:\\Users\\Harris Mirza\\Downloads\\Eight_bar_blues.mid")));
            sequencer.start();

            sequencer.addMetaEventListener(new MetaEventListener() {
                @Override
                public void meta(MetaMessage meta) {
                    if(meta.getType() == 47)
                    {
                        sequencer.close();
                    }
                }
            });

            while (sequencer.isOpen()){}
        }
    }
}

Java Sound Midi输出到硬件键盘

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