Android中对于文件操作除了java的基础库汇总的IO、File等之外，还提供了几种API

1、Context类提供的openFileOutput()和openFileInput()两个方法分别获取IO流，然后就可以进行相关读写操作了。
　　写操作中有个文件的操作模式的参数，也是Context提供的几个常量：MODE_PRIVATE,覆盖文件，默认模式；
　　MODE_APPEND,追加内容，不存在就新建。
　　//读取文件
    public String load(Context context,String fileName)
    {
        FileInputStream is=null;
        BufferedReader reader=null;
        StringBuilder result=new StringBuilder();
        try {
            is=context.openFileInput(fileName);
            reader = new BufferedReader(new InputStreamReader(is));
            String l="";
            while((l=reader.readLine())!=null)
            {
                result.append(l);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        finally {
            if(reader!=null)
            {
                try {
                    reader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return result.toString();
    }

//写入文件   
 public boolean write(Context context,String fileName,String content)
    {
        FileOutputStream os=null;
        BufferedWriter writer=null;
        try {
            os=context.openFileOutput(fileName,context.MODE_APPEND);
            writer=new BufferedWriter(new OutputStreamWriter(os));
            writer.write(content);
            return true;
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        finally {
            if(writer!=null)
            {
                try {
                    writer.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return false;
    }

        Log.i("info","getDataDirectory()"+Environment.getDataDirectory().getAbsolutePath());
        Log.i("info","getRootDirectory()"+Environment.getRootDirectory().getAbsolutePath());
        Log.i("info","getExternalStorageDirectory()"+Environment.getExternalStorageDirectory().getAbsolutePath());
        Log.i("info","getExternalStoragePublicDirectory()"+Environment.getExternalStoragePublicDirectory("basePath").getAbsolutePath());