求助java大神。java流中拷贝问题

File oldfile = new File(oldPath);
if (oldfile.exists()) { //文件存在时
InputStream inStream = new FileInputStream(oldPath); //读入原文件 路径
FileOutputStream fs = new FileOutputStream(newPath); //要输出的路径
byte[] buffer = new byte[512];
int length =0;
while ( (byteread = inStream.read(buffer)) != -1) {
bytesum += byteread; //字节数 文件大小
fs.write(buffer, 0, length);
}
inStream.close();
}

BufferedWriter bWriter=new BufferedWriter(new FileWriter("b.mp3"));
BufferedReader bReader=new BufferedReader(new FileReader("a.mp3"));

bWriter.write(bReader.read());