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);  
    }