android开发实现文件读写

/**
* 文件读取
* @param is 文件的输入流
* @return 返回文件数组
*/
private byte[] read(InputStream is) {
  //缓冲区inputStream
  BufferedInputStream bis = null;
  //用于存储数据
  ByteArrayOutputStream baos = null;
  try {
    //每次读1024
    byte[] b = new byte[1024];
    //初始化
    bis = new BufferedInputStream(is);
    baos = new ByteArrayOutputStream();
    
    int length;
    while ((length = bis.read(b)) != -1) {
      //bis.read()会将读到的数据添加到b数组
      //将数组写入到baos中
      baos.write(b, 0, length);
    }
    return baos.toByteArray();

  } catch (IOException e) {
    e.printStackTrace();
  } finally {//关闭流
    try {
      if (bis != null) {
        bis.close();
      }
      if (is != null) {
        is.close();
      }

      if (baos != null) baos.close();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
  return null;
}

/**
 * 将数据写入文件中
 * @param buffer 写入数据
 * @param fos  文件输出流
 */
private void write(byte[] buffer, FileOutputStream fos) {
  //缓冲区OutputStream
  BufferedOutputStream bos = null;
  try {
    //初始化
    bos = new BufferedOutputStream(fos);
    //写入
    bos.write(buffer);
    //刷新缓冲区
    bos.flush();
  } catch (IOException e) {
    e.printStackTrace();
  } finally {//关闭流
    try {
      if (bos != null) {
        bos.close();
      }
      if (fos != null) {
        fos.close();
      }
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
}

//获取文件输入流
InputStream mRaw = getResources().openRawResource(R.raw.core);

//读取文件
byte[] bytes = read(mRaw);

//创建文件(getFilesDir()路径在data/data/<包名>/files,需要root才能看到路径)
File file = new File(getFilesDir(), "hui.mp3");
boolean newFile = file.createNewFile();

//写入
if (bytes != null) {
 FileOutputStream fos = openFileOutput("hui.mp3", Context.MODE_PRIVATE);
 write(bytes, fos);
}