Question

java 获取歌曲文件的信息

我用FileInputStream实例了一个歌曲的文件信息
然后我想改写里面的一些信息，比如歌曲的标题(不是文件名)
可是发现好象没有这种方法
谁知道要怎么做啊？

Answer 1

这个具体的倒是不太清楚.不过你可以看看java开源播放器YOYOPlayer是如何实现的.以下是java开源播放器YOYOPlayer歌曲列表的实现,希望能对你有所帮助:
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package com.hadeslee.yoyoplayer.playlist;

import com.hadeslee.yoyoplayer.util.*;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;
import java.util.Iterator;
import java.util.List;
import java.util.StringTokenizer;
import java.util.Vector;

/**
* 一个播放列表的基本实现
* @author hadeslee
*/
public class BasicPlayList implements PlayList {

private static final long serialVersionUID = 20071214L;
protected Vector<PlayListItem> playList;
protected int currentIndex = -1;
protected boolean isModified;
protected String M3UHome;//MP3U格式列表的位置
protected String PLSHome;//PLS格式列表的位置
private String name;//表示此播放列表的名字
private Config config;//全局的配置对象
private PlayListItem playing;//正在播放的项
public BasicPlayList(Config config) {
this.config = config;
playList = new Vector<PlayListItem>();
}

public boolean load(String filename) {
setModified(true);
boolean loaded = false;
if ((filename != null) && (filename.toLowerCase().endsWith(".m3u"))) {
loaded = loadM3U(filename);
} else if ((filename != null) && (filename.toLowerCase().endsWith(".pls"))) {
loaded = loadPLS(filename);
}
return loaded;
}

protected boolean loadM3U(String filename) {
boolean loaded = false;
BufferedReader br = null;
try {
// Playlist from URL ? (http:, ftp:, file: ....)
if (Config.startWithProtocol(filename)) {
br = new BufferedReader(new InputStreamReader((new URL(filename)).openStream()));
} else {
br = new BufferedReader(new FileReader(filename));
}
String line = null;
String songName = null;
String songFile = null;
String songLength = null;
while ((line = br.readLine()) != null) {
if (line.trim().length() == 0) {
continue;
}
if (line.startsWith("#")) {
if (line.toUpperCase().startsWith("#EXTINF")) {
int indA = line.indexOf(",", 0);
if (indA != -1) {
songName = line.substring(indA + 1, line.length());
}
int indB = line.indexOf(":", 0);
if (indB != -1) {
if (indB < indA) {
songLength = (line.substring(indB + 1, indA)).trim();
}
}
}
} else {
songFile = line;
if (songName == null) {
songName = songFile;
}
if (songLength == null) {
songLength = "-1";
}
PlayListItem pli = null;
if (Config.startWithProtocol(songFile)) {
// URL.
pli = new PlayListItem(songName, songFile, Long.parseLong(songLength), false);
} else {
// File.
File f = new File(songFile);
if (f.exists()) {
pli = new PlayListItem(songName, songFile, Long.parseLong(songLength), true);
} else {
// Try relative path.
f = new File(config.getLastDir() + songFile);
if (f.exists()) {
pli = new PlayListItem(songName, config.getLastDir() + songFile, Long.parseLong(songLength), true);
} else {
// Try optional M3U home.
if (M3UHome != null) {
if (Config.startWithProtocol(M3UHome)) {
pli = new PlayListItem(songName, M3UHome + songFile, Long.parseLong(songLength), false);
} else {
pli = new PlayListItem(songName, M3UHome + songFile, Long.parseLong(songLength), true);
}
}
}
}
}
if (pli != null) {
this.appendItem(pli);
}
songFile = null;
songName = null;
songLength = null;
}
}
loaded = true;
} catch (Exception e) {
} finally {
try {
if (br != null) {
br.close();
}
} catch (Exception ioe) {
}
}
name = Util.getSongName(new File(filename));
return loaded;
}

protected boolean loadPLS(String filename) {
boolean loaded = false;
BufferedReader br = null;
try {
// Playlist from URL ? (http:, ftp:, file: ....)
if (Config.startWithProtocol(filename)) {
br = new BufferedReader(new InputStreamReader((new URL(filename)).openStream()));
} else {
br = new BufferedReader(new FileReader(filename));
}
String line = null;
String songName = null;
String songFile = null;
String songLength = null;
while ((line = br.readLine()) != null) {
if (line.trim().length() == 0) {
continue;
}
if ((line.toLowerCase().startsWith("file"))) {
StringTokenizer st = new StringTokenizer(line, "=");
st.nextToken();
songFile = st.nextToken().trim();
} else if ((line.toLowerCase().startsWith("title"))) {
StringTokenizer st = new StringTokenizer(line, "=");
st.nextToken();
songName = st.nextToken().trim();
} else if ((line.toLowerCase().startsWith("length"))) {
StringTokenizer st = new StringTokenizer(line, "=");
st.nextToken();
songLength = st.nextToken().trim();
}
// New entry ?
if (songFile != null) {
PlayListItem pli = null;
if (songName == null) {
songName = songFile;
}
if (songLength == null) {
songLength = "-1";
}
if (Config.startWithProtocol(songFile)) {
// URL.
pli = new PlayListItem(songName, songFile, Long.parseLong(songLength), false);
} else {
// File.
File f = new File(songFile);
if (f.exists()) {
pli = new PlayListItem(songName, songFile, Long.parseLong(songLength), true);
} else {
// Try relative path.
f = new File(config.getLastDir() + songFile);
if (f.exists()) {
pli = new PlayListItem(songName, config.getLastDir() + songFile, Long.parseLong(songLength), true);
} else {
// Try optional PLS home.
if (PLSHome != null) {
if (Config.startWithProtocol(PLSHome)) {
pli = new PlayListItem(songName, PLSHome + songFile, Long.parseLong(songLength), false);
} else {
pli = new PlayListItem(songName, PLSHome + songFile, Long.parseLong(songLength), true);
}
}
}
}
}
if (pli != null) {
this.appendItem(pli);
}
songName = null;
songFile = null;
songLength = null;
}
}
loaded = true;
} catch (Exception e) {
} finally {
try {
if (br != null) {
br.close();
}
} catch (Exception ioe) {
}
}
name = Util.getSongName(new File(filename));
return loaded;
}

public boolean save(String filename) {
// Implemented by C.K
if (playList != null) {
BufferedWriter bw = null;
try {
bw = new BufferedWriter(new FileWriter(filename));
bw.write("#EXTM3U");
bw.newLine();
Iterator<PlayListItem> it = playList.iterator();
while (it.hasNext()) {
PlayListItem pli = it.next();
bw.write("#EXTINF:" + pli.getM3UExtInf());
bw.newLine();
bw.write(pli.getLocation());
bw.newLine();
}
return true;
} catch (IOException e) {
} finally {
try {
if (bw != null) {
bw.close();
}
} catch (IOException ioe) {
}
}
}
return false;
}

public void addItemAt(PlayListItem pli, int pos) {
playList.add(pos, pli);
for (int i = 0; i < playList.size(); i++) {
if (playList.get(i).isSelected()) {
currentIndex = i;
}
}
setModified(true);
if (Config.getConfig().getReadTagInfoStrategy().equals(Config.READ_WHEN_ADD)) {
pli.getTagInfo();
}
}

public void removeItem(PlayListItem pli) {
playList.remove(pli);
setModified(true);
for (int i = 0; i < playList.size(); i++) {
if (playList.get(i).isSelected()) {
currentIndex = i;
}
}
}

public void removeItemAt(int pos) {
playList.remove(pos);
setModified(true);
for (int i = 0; i < playList.size(); i++) {
if (playList.get(i).isSelected()) {
currentIndex = i;
}
}
}

public void removeAllItems() {
playList.clear();
currentIndex = -1;
setModified(true);
}

public void appendItem(PlayListItem pli) {
playList.add(pli);
setModified(true);
if (Config.getConfig().getReadTagInfoStrategy().equals(Config.READ_WHEN_ADD)) {
pli.getTagInfo();
}
}

public void sortItems(int sortmode) {
}

public PlayListItem getItemAt(int pos) {
if (pos < playList.size() && pos > -1) {
return playList.get(pos);
}
return null;
}

public Vector<PlayListItem> getAllItems() {
return playList;
}

public int getPlaylistSize() {
return playList.size();
}

public void shuffle() {
int size = playList.size();
if (size < 2) {
return;
}
List<PlayListItem> v = playList;
playList = new Vector<PlayListItem>(size);
while ((size = v.size()) > 0) {
playList.add(v.remove((int) (Math.random() * size)));
}
begin();
//此次可能不一定需要这个方法,因为本身此方法就是打
//乱播放列表的顺序,所以此时再点击下一首不一定就是
//当前播放的歌曲的下一首
for (int i = 0; i < playList.size(); i++) {
if (playList.get(i).isSelected()) {
currentIndex = i;
}
}
}

public PlayListItem getCursor() {
if ((currentIndex < 0) || (currentIndex >= playList.size())) {
return null;
}
return getItemAt(currentIndex);
}

public void begin() {
currentIndex = -1;
if (getPlaylistSize() > 0) {
currentIndex = 0;
}
setModified(true);
}

public int getSelectedIndex() {
return currentIndex;
}

public int getIndex(PlayListItem pli) {
return playList.indexOf(pli);
}

public void nextCursor() {
//如果是随机播放,则随机取一个下标
if (config.getPlayStrategy() == Config.RANDOM_PLAY) {
currentIndex = (int) (Math.random() * playList.size());
//否则就按顺序
} else if (config.getPlayStrategy() == Config.ORDER_PLAY) {
currentIndex++;
}
if (config.isRepeatEnabled() && currentIndex >= playList.size()) {
currentIndex = 0;
}

}

public void previousCursor() {
//如果是随机播放,则随机取一个下标
if (config.getPlayStrategy() == Config.RANDOM_PLAY) {
currentIndex = (int) (Math.random() * playList.size());
//否则就按顺序
} else if (config.getPlayStrategy() == Config.ORDER_PLAY) {
currentIndex--;
}
if (config.isRepeatEnabled() && currentIndex < 0) {
currentIndex = playList.size() - 1;
}
}

public boolean setModified(boolean set) {
return isModified = set;
}

public boolean isModified() {
return isModified;
}

public void setCursor(int index) {
currentIndex = index;
playing = playList.get(index);
}

public void setName(String name) {
this.name = name;
}

public String getName() {
return name;
}

/**
* Get M3U home for relative playlist.
*
* @return
*/
public String getM3UHome() {
return M3UHome;
}

/**
* Set optional M3U home for relative playlist.
*
* @param string
*/
public void setM3UHome(String string) {
M3UHome = string;
}

/**
* Get PLS home for relative playlist.
*
* @return
*/
public String getPLSHome() {
return PLSHome;
}

/**
* Set optional PLS home for relative playlist.
*
* @param string
*/
public void setPLSHome(String string) {
PLSHome = string;
}

public String toString() {
return name;
}

public void setItemSelected(PlayListItem pl, int index) {
if (pl == null) {
return;
}
// for (PlayListItem p : playList) {
// p.setSelected(false);
// }
// pl.setSelected(true);
this.currentIndex = index;
}
}

Answer 2

没弄过 但是如果想修改歌曲的信息应该在你编辑后重新的生成一个歌曲文件吧

希望对你能有所帮助

Answer 3

等我明天给你说