java播放MP3长度不对

符千青 2016-07-11 10:47:28

我在论坛上找了一段播放MP3的代码，，，现在我想加一个显示播放进度的进步条。。。然后我发现同一个输入流在两个地方读到的长度居然不一样



package com.inkbox.music;



import java.io.BufferedWriter;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.FileWriter;

import java.io.IOException;

import java.io.PrintWriter;

import java.awt.BorderLayout;

import java.awt.FileDialog;

import java.awt.Frame;

import java.awt.GridLayout;

import java.awt.Label;

import java.awt.List;

import java.awt.Menu;

import java.awt.MenuBar;

import java.awt.MenuItem;

import java.awt.MenuShortcut;

import java.awt.Panel;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.awt.event.KeyEvent;

import java.awt.event.MouseAdapter;

import java.awt.event.MouseEvent;

import java.awt.event.WindowAdapter;

import java.awt.event.WindowEvent;



import javax.sound.sampled.AudioFormat;

import javax.sound.sampled.AudioInputStream;

import javax.sound.sampled.AudioSystem;

import javax.sound.sampled.DataLine;

import javax.sound.sampled.SourceDataLine;

import javax.swing.JButton;

import javax.swing.JProgressBar;

import javax.swing.UIManager;

import javax.swing.UnsupportedLookAndFeelException;



import javazoom.jl.decoder.Bitstream;

import javazoom.jl.decoder.Header;



@SuppressWarnings("serial")

public class MusicPlayer extends Frame {

	boolean isStop = true; // 控制播放线程

	boolean hasStop = true; // 播放线程状态

	String filepath; // 播放文件目录

	String filename; // 播放文件名称

	long audioLength = 0;// 音频总长度

	long playLength = 0;// 记录已播放长度

	List list;// 文件列表

	Label labelfilepath; // 播放目录显示标签

	Label labelfilename; // 播放文件显示标签



	AudioInputStream audioInputStream; // 文件流

	AudioFormat audioFormat; // 文件格式

	SourceDataLine sourceDataLine; // 输出设备



	public MusicPlayer() {

		try {

			UIManager.setLookAndFeel("com.jtattoo.plaf.acryl.AcrylLookAndFeel");

			// new AlloyLookAndFeel().

		} catch (ClassNotFoundException | InstantiationException

				| IllegalAccessException | UnsupportedLookAndFeelException e1) {

			e1.printStackTrace();

		}

		// 设置窗体属性

		setLayout(new BorderLayout());

		setTitle("MP3音乐播放器");

		setSize(350, 370);

		// 建立菜单栏

		MenuBar menubar = new MenuBar();

		Menu menufile = new Menu("文件");

		MenuItem menuopen = new MenuItem("打开", new MenuShortcut(KeyEvent.VK_O));

		menufile.add(menuopen);

		menufile.addActionListener(new ActionListener() {

			public void actionPerformed(ActionEvent e) {

				open();

			}

		});

		menubar.add(menufile);

		setMenuBar(menubar);

		// 文件列表

		list = new List(10);

		list.addMouseListener(new MouseAdapter() {

			public void mouseClicked(MouseEvent e) {

				// 双击时处理

				if (e.getClickCount() == 2) {

					// 播放选中的文件

					filename = list.getSelectedItem();



					play();

				}

			}

		});

		add(list, "Center");

		// 信息显示

		Panel panel = new Panel(new GridLayout(4, 1));

		labelfilepath = new Label("播放目录：");

		panel.add(labelfilepath);



		button = new JButton("\u6682\u505C");

		button.addActionListener(new ActionListener() {

			public void actionPerformed(ActionEvent e) {

				synchronized (playThread) {

					pause = !pause;

				}



			}

		});

		labelfilename = new Label("播放文件：");

		panel.add(labelfilename);

		panel.add(button);



		progressBar = new JProgressBar();

		progressBar.setStringPainted(true);

		panel.add(progressBar);

		add(panel, "North"); // 注册窗体关闭事件

		addWindowListener(new WindowAdapter() {

			public void windowClosing(WindowEvent e) {

				System.exit(0);

			}

		});

		setVisible(true);

	}



	// 打开

	private void open() {

		FileDialog dialog = new FileDialog(this, "Open", 0);

		dialog.setVisible(true);

		filepath = dialog.getDirectory();

		if (filepath != null) {

			labelfilepath.setText("播放目录：" + filepath);

			// 显示文件列表

			list.removeAll();

			File filedir = new File(filepath);

			File[] filelist = filedir.listFiles();

			for (File file : filelist) {

				String filename = file.getName().toLowerCase();

				if (filename.endsWith(".mp3") || filename.endsWith(".wav")) {

					list.add(filename);

				}

			}

		}

	}



	// 播放

	private void play() {

		try {

			isStop = true;

			// 停止播放线程

			// 等待播放线程停止,等待已播放歌曲停止

			System.out.print("开始播放：" + filename);

			while (!hasStop) {

				System.out.print(".");

				try {

					Thread.sleep(10);

				} catch (Exception e) {

					e.printStackTrace();

				}

			}

			System.out.println("");



			File file = new File(filepath + filename);

			// audioLength = file.length();

			labelfilename.setText("播放文件：" + filename);

			FileInputStream fis = new FileInputStream(file);

			int b = fis.available();

			Bitstream bt = new Bitstream(fis);

			Header h = bt.readFrame();

			int time = (int) h.total_ms(b);



			int i = time / 1000;

			System.out.println(i / 60 + ":" + i % 60);



			// 取得文件输入流

			audioInputStream = AudioSystem.getAudioInputStream(file);

			audioFormat = audioInputStream.getFormat();

			audioLength = getLength();

			System.out.println(audioLength);

			audioInputStream = AudioSystem.getAudioInputStream(file);



			// 转换MP3文件编码

			if (audioFormat.getEncoding() != AudioFormat.Encoding.PCM_SIGNED) {

				audioFormat = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED,

						audioFormat.getSampleRate(), 16,

						audioFormat.getChannels(),

						audioFormat.getChannels() * 2,

						audioFormat.getSampleRate(), false);

				audioInputStream = AudioSystem.getAudioInputStream(audioFormat,

						audioInputStream);

			}



			// 打开输出设备

			DataLine.Info dataLineInfo = new DataLine.Info(

					SourceDataLine.class, audioFormat,

					AudioSystem.NOT_SPECIFIED);

			sourceDataLine = (SourceDataLine) AudioSystem.getLine(dataLineInfo);

			sourceDataLine.open(audioFormat);

			sourceDataLine.start();

			// 创建独立线程进行播放

			isStop = false;

			playThread = new Thread(new PlayThread());

			playThread.start();

		} catch (Exception e) {

			e.printStackTrace();

		}

	}



	Thread playThread;



	public static void main(String args[]) {

		new MusicPlayer();

		// AudioFilePlayer asp=new AudioFilePlayer();

		// asp.play("E:\\music\\郁可唯 - 暖心.mp3");

	}



	boolean pause = false;

	private JButton button;

	private JProgressBar progressBar;



	class PlayThread extends Thread {

		byte tempBuffer[] = new byte[320];

		public void run() {

			try {

				int cnt;

				hasStop = false;

				int readTime = 0;

				int writeTime = 0;

				playLength = 0;

				int pl=0;

				while (true) {

					// 读取数据到缓存数据

					// while ((cnt = audioInputStream.read(tempBuffer, 0,

					// tempBuffer.length)) != -1) {

					// System.out.println("线程未死");

					Thread.sleep(1);// 稍微等待，否则暂停后无法重启，不宜过久，否则声音不连续

					if (!pause) {

						cnt = audioInputStream.read(tempBuffer, 0,

								tempBuffer.length);

						readTime++;

						

						if (cnt == -1) {

							break;

						}

						pl+=cnt;

						if (cnt > 0) {

							int writeLength = sourceDataLine.write(tempBuffer,

									0, cnt);

							writeTime++;

							// write(playLength);

							// 写入的数据总会大于文件总长度

							playLength += writeLength;

							float d_audioLength = (float) (audioLength / 100);

							float d_playLength = (float) (playLength / 100);

							float d = d_playLength / d_audioLength * 100;

//							System.out.println("pl=" + pl

//									+ " audioLength=" + audioLength

//									+ "  playLength=" + playLength + "  百分比="

//									+ d + "  writeLenght=" + writeLength);

//							pause = true;

							progressBar.setValue((int) d);



							// 写入缓存数据

						}

					}

					// 无论此时是否处于暂停状态，换歌的时候都需要停止当前线程

					if (isStop) {

						if (pause) {

							pause = false;

						}

						playLength = 0;

						break;

					}

				}

				// Block等待临时数据被输出为空

				sourceDataLine.drain();

				sourceDataLine.close();

				hasStop = true;

				System.out.println("播放结束--pause=" + pause);

				System.out.println("writeTime=" + writeTime + " readTime="

						+ readTime);

				System.out.println("audioLenget=" + audioLength

						+ " playLength=" + playLength);

			} catch (Exception e) {

				e.printStackTrace();

				System.exit(0);

			}

		}

	}



	public long getLength() {

		long len = 0;



		byte btes[] = new byte[320];

		int temp = 0;

		int time=0;

		try {

			while ((temp = audioInputStream.read(btes, 0, btes.length)) != -1) {

				len += temp;

				time++;

			}

		} catch (IOException e) {

			e.printStackTrace();

		} finally {

			try {

				audioInputStream.close();

			} catch (IOException e) {

				e.printStackTrace();

			}

		}

		System.out.println("len="+len+" time="+time);

		return len;

	}

	

}