response.setHeader("Content-Type", "audio/mp3");

File file = new File(localhost_dir);
int len_l = (int) file.length();
byte[] buf = new byte[4096];
FileInputStream fis = new FileInputStream(file);
OutputStream out = response.getOutputStream();
len_l = fis.read(buf);
while (len_l != -1) {
    out.write(buf, 0, len_l);
    len_l = fis.read(buf);
}

這個有時候讀取文件為什么會斷流? while 到一半就斷了
但是mp3文件是可以正常播放完的