将数据以文件的形式保存

废话不多说，直接上代码，私有文件在data/data/appName/下，不能将文件拷贝

/**
 * 将数据写入到私有文件中
 * @param context
 * @param data
 * @param fileName
 */
private void saveDataToFile(Context context, String data, String fileName)
{
    FileOutputStream fileOutputStream = null;
    BufferedWriter bufferedWriter = null;
    try
    {

        fileOutputStream = context.openFileOutput(fileName,
                Context.MODE_APPEND);
        bufferedWriter = new BufferedWriter(
                new OutputStreamWriter(fileOutputStream));
        bufferedWriter.write(data);
        Toast.makeText(context, "存储的数据为"+data, Toast.LENGTH_SHORT).show();

    }
    catch (IOException e)
    {
        e.printStackTrace();
    }

    finally
    {
        try
        {
            if (bufferedWriter != null)
            {
                bufferedWriter.close();
            }
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }
}

/**
 * 从文件中读取数据
 * @param context context
 * @param fileName 文件名
 * @return 从文件中读取的数据
 */
private String loadDataFromFile(Context context, String fileName)
{
    FileInputStream fileInputStream = null;
    BufferedReader bufferedReader = null;
    StringBuilder stringBuilder = new StringBuilder();
    try
    {
        /**
         * 注意这里的fileName不要用绝对路径，只需要文件名就可以了，系统会自动到data目录下去加载这个文件
         */
        fileInputStream = context.openFileInput(fileName);
        bufferedReader = new BufferedReader(
                new InputStreamReader(fileInputStream));
        String result = "";
        while ((result = bufferedReader.readLine()) != null)
        {
            stringBuilder.append(result);
        }
    }
    catch (IOException e)
    {
        e.printStackTrace();
    }
    finally
    {
        if (bufferedReader != null)
        {
            try
            {
                bufferedReader.close();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
        }
    }
    return stringBuilder.toString();
}

以文本形式保存到指定文件夹可以进行拷贝

/**
 * 将数据以文本的形式保存到指定目录下
 * @param bytes
 */
private void saveToPublic(byte[] bytes){
    String status = Environment.getExternalStorageState();
    if (status.equals(Environment.MEDIA_MOUNTED)){
        try{
            String filename = newDate();
            File file = new File(Environment.getExternalStorageDirectory()+"/"+"ZRY",filename);
           if (!file.exists()){
               File dir = new File(file.getParent());
               dir.mkdirs();
           }

            FileOutputStream outStream = new FileOutputStream(file+".txt",true);    //文件输出流用于将数据写入文件
            outStream.write(bytes);
            outStream.close();  //关闭文件输出流
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

/**
 * 返回一个时间的名称
 * @return
 */
public static String newDate(){
    Time time = new Time();
    time.setToNow();
    int year = time.year;
    int month = time.month+1;
    int monthDay = time.monthDay;
    int hour = time.hour;
    int minute = time.minute;
    int second = time.second;
    return ""+year+month+monthDay+hour+minute+second;

}