擷取MP3和WAV格式的長度（毫秒）

WAV格式

AudioInputStream audioInputStream = AudioSystem.getAudioInputStream(file);

AudioFormat format = audioInputStream.getFormat();

long audioFileLength = file.length();

int frameSize = format.getFrameSize();

float frameRate = format.getFrameRate();

Float durationInSeconds = (audioFileLength / (frameSize * frameRate))*1000;

MP3格式

MP3File f = (MP3File) AudioFileIO.read(file);

MP3AudioHeader audioHeader = (MP3AudioHeader) f.getAudioHeader();

preciseTrackLength = audioHeader.getPreciseTrackLength() * 1000;