Question

import javax.sound.sampled.*;
import java.io.*;
import javax.swing.*;

class muse{
// this plays music files

  Thread.UncaughtExceptionHandler h = new Thread.UncaughtExceptionHandler() {
    public void uncaughtException(Thread music, Throwable ex) {
    System.out.println("Uncaught exception: " + ex);
  }};

  String dian="yun.wav";

  static void mate(String dian)
  {
    Thread music = new Thread(dian)
    {
      public void run(String dian)
      {
        try
        {
          Clip clip= null;
          File in = new File(dian);
          AudioInputStream audioInputStream = AudioSystem.getAudioInputStream(in);
          clip = AudioSystem.getClip();
          clip.open(audioInputStream);
          clip.start();
          JOptionPane.showMessageDialog(null, "Click OK to stop music");
          clip.drain();
        }
        catch (UnsupportedAudioFileException | IOException | LineUnavailableException ex)
        {
          ex.printStackTrace();
        }
        throw new RuntimeException();
      }
    };
  }

  public static void main(String args[]) throws InterruptedException {
    music.start();
  }

}

我创建了这段代码，以便我可以在另一个.java文件中输入歌曲文件的名称，但是即使netbeans中没有红色错误，代码最终也是无法编译的。如果我删除静态void配合（String dian）{} 代码工作正常，任何人都可以帮助解释它为什么不编译或允许代码从另一个.java文件运行的替代方案

Answer 1

静态方法music中声明的mate对象在本地声明，在主方法中无法访问。

尝试修改您的示例：

static Thread mate(String diane) {
    return new Thread(dian){
    ...
}

然后在你的主要方法

public static void main(String args[]) throws InterruptedException {
    Thread music = mate("filename");
    music.start();
}

Answer 2

编译失败可能发生在

public static void main(String args[]) throws InterruptedException {
       mate(dian);
       music.start();
}

因为 music 变量未在main（）可访问的作用域中定义。

轻松破解你可以将线程音乐变量设为私有静态变量，因此主要可以访问它。

private static String dian = "yun.wav";
private static Thread music = null;

static void mate(String dian){
          music = new Thread(dian){...}
}

Answer 3

您的代码存在多个错误或错误：

1）main方法看不到音乐，你可以声明它是一个可见的类变量

2）你正在向run（）传递一个参数（现在它没有覆盖Thread类方法）所以当你在音乐上调用start（）时它将不会做什么，因为它会调用Thread类的Run方法。这就是你需要删除传递给run（）的String参数的原因。

3）你正在硬编码文件名。你可以从命令行把它作为输入。

class muse{
    //music will be available to main method
    private static Thread music ;
    // this plays music files

    Thread.UncaughtExceptionHandler h = new Thread.UncaughtExceptionHandler() {
    public void uncaughtException(Thread music, Throwable ex) {
        System.out.println("Uncaught exception: " + ex);
    }
    };

     static void mate(String dian){
    music = new Thread(dian){

    //removed argument so it can run when you call start(); 
    @Override
    public void run(){

      try{
        Clip clip= null;
        File in = new File(dian);
        AudioInputStream audioInputStream = AudioSystem.getAudioInputStream(in);
        clip = AudioSystem.getClip();
        clip.open(audioInputStream);
        clip.start();
        JOptionPane.showMessageDialog(null, "Click OK to stop music");
        clip.drain();
    } catch (UnsupportedAudioFileException | IOException | LineUnavailableException ex) {
            ex.printStackTrace();
    }
    throw new RuntimeException();
    }
    }; 
    }
    public static void main(String args[]) throws InterruptedException {
     String dian=null;
        //you can take dian as inut file from command line also using scanner
        Scanner s=new Scanner(System.in);
        dian=s.next();
        s.close();
        ////////////

        //call Mate() so it will create a new new music thread with clip assigned to dian;  
    mate(dian);
    //start music
    music.start();
    }
    }

错误的sym类型，代码无法编译

3 个答案: