Android数据文件存储

        Date now = new Date();
        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd-HH:mm:ss");
        String filename = dateFormat.format( now );
        File accelerometerDataFile = new File(getExternalCacheDir(), filename+".csv");
        PrintWriter printWriter =
                    new PrintWriter(new BufferedWriter(new FileWriter(dataFile)));

            printWriter.println(CSV_HEADER);
        if (printWriter != null)
        {
            StringBuffer sb = new StringBuffer()
                    .append(z).append(CSV_DELIM)
                    .append((eventTime / 1000000) - startTime);

            printWriter.println(sb.toString());
            if (printWriter.checkError())
            {
                Log.w(TAG, "Error writing sensor event data");
            }
        }

        if (printWriter != null)
        {
            printWriter.close();
        }