Java结果1错误

Question

我想创建一个由这些注释组成的midi文件。我从网上取了这个代码。如果我能找出这个问题，我就能走得更远。当我运行这个应用程序时，我只得到一个错误调用"javaresult1"错误。我需要的是，在我运行这个之后，应该会生成一个由我传递的注释组成的midi文件。完整的代码可用。

public class CreateSequence{
  private static final int VELOCITY = 64;
  public static void main(String[] args) {
    if (args.length != 1) {
        printUsageAndExit();
    }
    File outputFile = new File(args[0]);
    Sequence    sequence = null;
    try {
        sequence = new Sequence(Sequence.PPQ, 1);
    } catch (InvalidMidiDataException e) {
        e.printStackTrace();
        System.exit(1);
    }   
    Track track = sequence.createTrack();
    // first chord: C major
    track.add(createNoteOnEvent(60, 0));
    track.add(createNoteOnEvent(64, 0));
    track.add(createNoteOnEvent(67, 0));
    track.add(createNoteOnEvent(72, 0));
    track.add(createNoteOffEvent(60, 1));
    track.add(createNoteOffEvent(64, 1));
    track.add(createNoteOffEvent(67, 1));
    track.add(createNoteOffEvent(72, 1));
    // second chord: f minor N
    track.add(createNoteOnEvent(53, 1));
    track.add(createNoteOnEvent(65, 1));
    track.add(createNoteOnEvent(68, 1));
    track.add(createNoteOnEvent(73, 1));
    track.add(createNoteOffEvent(63, 2));
    track.add(createNoteOffEvent(65, 2));
    track.add(createNoteOffEvent(68, 2));
    track.add(createNoteOffEvent(73, 2));
    // third chord: C major 6-4
    track.add(createNoteOnEvent(55, 2));
    track.add(createNoteOnEvent(64, 2));
    track.add(createNoteOnEvent(67, 2));
    track.add(createNoteOnEvent(72, 2));
    track.add(createNoteOffEvent(64, 3));
    track.add(createNoteOffEvent(72, 3));
    // forth chord: G major 7
    track.add(createNoteOnEvent(65, 3));
    track.add(createNoteOnEvent(71, 3));
    track.add(createNoteOffEvent(55, 4));
    track.add(createNoteOffEvent(65, 4));
    track.add(createNoteOffEvent(67, 4));
    track.add(createNoteOffEvent(71, 4));
    // fifth chord: C major
    track.add(createNoteOnEvent(48, 4));
    track.add(createNoteOnEvent(64, 4));
    track.add(createNoteOnEvent(67, 4));
    track.add(createNoteOnEvent(72, 4));
    track.add(createNoteOffEvent(48, 8));
    track.add(createNoteOffEvent(64, 8));
    track.add(createNoteOffEvent(67, 8));
    track.add(createNoteOffEvent(72, 8));
    //Now we just save the Sequence to the file we specified.
    //The '0' (second parameter) means saving as SMF type 0.
    //Since we have only one Track, this is actually the only option
    //(type 1 is for multiple tracks).
    try {
        MidiSystem.write(sequence, 0, outputFile);
    } catch (IOException e) {
        e.printStackTrace();
        System.exit(1);
    }
  }
  private static MidiEvent createNoteOnEvent(int nKey, long lTick) {
    return createNoteEvent(ShortMessage.NOTE_ON, nKey, VELOCITY, lTick);
  }
  private static MidiEvent createNoteOffEvent(int nKey, long lTick) {
    return createNoteEvent(ShortMessage.NOTE_OFF, nKey, 0, lTick);
  }
  private static MidiEvent createNoteEvent(int nCommand, int nKey,
                                           int nVelocity, long lTick) {
    ShortMessage message = new ShortMessage();
    try {
        message.setMessage(nCommand, 0, nKey, nVelocity); // 0 always on channel 1
    } catch (InvalidMidiDataException e) {
        e.printStackTrace();
        System.exit(1);
    }
    MidiEvent event = new MidiEvent(message, lTick);
    return event;
  }
  private static void printUsageAndExit(){
        out("usage:");
        out("java CreateSequence <midifile>");
        System.exit(1);
  }
  private static void out(String strMessage) {
    System.out.println(strMessage);
  }
}

这是输出

   usage:
   java CreateSequence <midifile>
   Java Result: 1

Answer 1

您需要将输出文件名作为arg传递。它将以代码1退出，因为如果您没有使用正确的arg计数运行它，它将调用printUsafeAndExit（）。尝试将其运行为：

java CreateSequence output.mid

如果您在传递args时遇到困难（如果您使用Eclipse这样的IDE，初学者可能会感到困惑），只需删除以下检查：

if (args.length != 1) {
    printUsageAndExit();
}

并对输出文件进行硬编码：

File outputFile = new File("output.mid");

Answer 2

您是如何调用这个Java程序的？该代码要求在命令行中传递一个参数。从输出来看，它看起来像方法

private static void printUsageAndExit()
{
    out("usage:");
    out("java CreateSequence <midifile>");
    System.exit(1);
}

正在被调用。运行程序时，您需要将文件名传递（我相信）给程序