android 文件保存到应用跟sd卡中

<span style="font-size:18px;">1.权限添加<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/><uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>public static String getDataFolderPath(Context paramContext) {        return Environment.getDataDirectory() + "/data/"                + paramContext.getPackageName() + "/files";    }    public static String getMyFileDir(Context context){        return context.getFilesDir().toString();    }        public static String getMyCacheDir(Context context){        return context.getCacheDir().toString();    }    /**     * @desc 保存内容到文件中     * @param fileName     * @param content     * @throws Exception     */    public static void save(Context context, String fileName, String content, int module) {        try {            FileOutputStream os = context.openFileOutput(fileName, module);            os.write(content.getBytes());            os.close();        } catch (Exception e) {            e.printStackTrace();        }    }        /**     * @desc 读取文件内容     * @param fileName     * @return     */    public static String read(Context context, String fileName){                try {            FileInputStream fis = context.openFileInput(fileName);            ByteArrayOutputStream bos = new ByteArrayOutputStream();            byte[] b = new byte[1024];            int len = 0;            while((len = fis.read(b)) != -1){                bos.write(b, 0, len);            }            byte[] data = bos.toByteArray();            fis.close();            bos.close();            return new String(data);        } catch (Exception e) {            e.printStackTrace();        }        return  null;    }            /**     * @desc 将文本内容保存到sd卡的文件中     * @param context     * @param fileName     * @param content     * @throws IOException     */    public static void saveToSDCard(Context context, String fileName, String content) throws IOException{                File file = new File(Environment.getExternalStorageDirectory(),fileName);        FileOutputStream fos = new FileOutputStream(file);        fos.write(content.getBytes());        fos.close();    }    /**     * @desc 读取sd卡文件内容     * @param fileName     * @return     * @throws IOException     */    public static String readSDCard(String fileName) throws IOException {                File file = new File(Environment.getExternalStorageDirectory(),fileName);        FileInputStream fis = new FileInputStream(file);        ByteArrayOutputStream bos = new ByteArrayOutputStream();        byte[] buffer =  new byte[1024];        int len = 0;        while((len = fis.read(buffer)) != -1)        {            bos.write(buffer, 0, len);        }        byte[]  data = bos.toByteArray();        fis.close();        bos.close();                return new String(data);    }</span>