Question

我想从互联网上拿xml，但每次从网上拿xml对我的应用程序来说都很慢，所以我想把它保存在本地目录中，下次我打开应用程序然后在后端再次从互联网上复制xml到我的xml

怎么做，有没有其他好办法解决这个问题？

Answer 1

请使用以下功能将文件写入SD卡。

    private  static String APP_DOC_DIR =  "file:///SDCard/BlackBerry/documents/MyAPP/";

public static void writeToSD(String fileName, String fileContent){
    FileConnection fconn = null;
        // APP_DOC_DIR is the directory name constant.
    try {
         FileConnection fc = (FileConnection)Connector.open(APP_DOC_DIR);
     // If no exception is thrown, the URI is valid but the folder may not exist.
     if (!fc.exists())
     {
         fc.mkdir();  // create the folder if it doesn't exist
     }
     fc.close();


        fconn = (FileConnection) Connector.open(APP_DOC_DIR + fileName ,Connector.READ_WRITE);          
        if (!fconn.exists()) {
            fconn.create();
        }
        fconn.setReadable(true);
        fconn.setWritable(true);
        OutputStream os = fconn.openOutputStream();
        os.write(fileContent.getBytes("UTF8"));
        os.flush();
        os.close();
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if (fconn!=null) {
            try {
                fconn.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

从SD卡读取文件如下。

public static String readFromSD(String fileName)
    {
        String resultString = "";
        int BUFFER_SIZE = 10000;
        InputStream inputStream = null;
        FileConnection fconn;
        try {
            fconn = (FileConnection) Connector.open( APP_DOC_DIR + fileName, Connector.READ);
            if (fconn.exists()) 
            {
                inputStream = fconn.openInputStream();
            }
            else
            {
                return "";
            }
            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
            byte[] buffer = new byte[BUFFER_SIZE];
            while (true) {
                int bytesRead = inputStream.read( buffer, 0, BUFFER_SIZE );
                if (bytesRead == -1)
                        break;
                byteArrayOutputStream.write( buffer, 0, bytesRead );
            }
            byteArrayOutputStream.flush();
            byte[] result = byteArrayOutputStream.toByteArray();
            byteArrayOutputStream.close();
            //resultString = new String(result,"UTF8");
            resultString = new String(result);

        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return resultString;
    }

如何在黑莓本地保存xml文件？

1 个答案: