android File存儲對象 File存儲到SD卡

android File存儲對象

1、保存對象到本地或SD卡

              public void fileSave(OAuthV1 oAuth_1){
    //保存在本地
    try {
        // 通過openFileOutput方法得到一個輸出流，方法參數爲創建的文件名（不能有斜槓），操作模式
        FileOutputStream fos = this.openFileOutput("oauth_1.out",Context.MODE_WORLD_READABLE);
        ObjectOutputStream oos = new ObjectOutputStream(fos);
        oos.writeObject(oAuth_1);// 寫入
        fos.close(); // 關閉輸出流
        //Toast.makeText(WebviewTencentActivity.this, "保存oAuth_1成功",Toast.LENGTH_LONG).show();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
        //Toast.makeText(WebviewTencentActivity.this, "出現異常1",Toast.LENGTH_LONG).show();
    } catch (IOException e) {
        e.printStackTrace();
        //Toast.makeText(WebviewTencentActivity.this, "出現異常2",Toast.LENGTH_LONG).show();
    }

    //保存在sd卡
    if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){

           File sdCardDir = Environment.getExternalStorageDirectory();//獲取SDCard目錄
           File sdFile = new File(sdCardDir, "oauth_1.out");


        try {
            FileOutputStream fos = new FileOutputStream(sdFile);
            ObjectOutputStream oos = new ObjectOutputStream(fos);
            oos.writeObject(oAuth_1);// 寫入
            fos.close(); // 關閉輸出流
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
           //Toast.makeText(WebviewTencentActivity.this, "成功保存到sd卡", Toast.LENGTH_LONG).show();

    }
}

需要注意的是，要保存的對象（OAuthV1）一定要實現了Serializable接口。

實現了Serializable接口對象才能被序列化。

2、從本地或SD卡中取出對象

（從本地取得保存的對象）

              public OAuthV1 readOAuth1() {
OAuthV1 oAuth_1 = null;
//String filename = "oauth_file.cfg";
        try {
            FileInputStream fis=this.openFileInput("oauth_1.out");   //獲得輸入流
            ObjectInputStream ois = new ObjectInputStream(fis);
            oAuth_1 = (OAuthV1)ois.readObject();

            //tv.setText(per.toString());                           //設置文本控件顯示內容
           // Toast.makeText(ShareTencentActivity.this,"讀取成功",Toast.LENGTH_LONG).show();//彈出Toast消息
        } catch (StreamCorruptedException e) {
            //Toast.makeText(ShareTencentActivity.this,"出現異常3",Toast.LENGTH_LONG).show();//彈出Toast消息
            e.printStackTrace();
        } catch (OptionalDataException e) {
            //Toast.makeText(ShareTencentActivity.this,"出現異常4",Toast.LENGTH_LONG).show();//彈出Toast消息
            e.printStackTrace();
        } catch (FileNotFoundException e) {
            //Toast.makeText(ShareTencentActivity.this,"出現異常5",Toast.LENGTH_LONG).show();//彈出Toast消息
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            //Toast.makeText(ShareTencentActivity.this,"出現異常6",Toast.LENGTH_LONG).show();//彈出Toast消息
            e.printStackTrace();
        }
return oAuth_1;

（2）從SD卡中取得保存的對象

public OAuthV1 readOAuth2() {
    OAuthV1 oAuth_1 = null;
    File sdCardDir = Environment.getExternalStorageDirectory();//獲取SDCard目錄
    File sdFile = new File(sdCardDir, "oauth_1.out");

    try {
        FileInputStream fis=new FileInputStream(sdFile);   //獲得輸入流
        ObjectInputStream ois = new ObjectInputStream(fis);
        oAuth_1 = (OAuthV1)ois.readObject();
        ois.close();
    } catch (StreamCorruptedException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (OptionalDataException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (ClassNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
          }

對SD卡操作別忘了加權限

        <!-- 在SDCard中創建與刪除文件的權限 -->
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
<!-- 往SDCard寫入數據的權限 -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>