在 Windows Phone 上讀取 BIG5 網頁

Windows Phone SDK 是不支援 BIG5 編碼的，它只支援三種編碼。

BigEndianUnicode、Unicode、UTF8

 

 

因此若要讀取 BIG5 的網頁，就必須自行將 BIG5 轉換為 Unicode，實作的主要重點在於：

1. 取得 BIG5 –> Unicode 轉換表。(BIG5.TXT)
2. 將轉換表改用 Dictionary 型態儲存。
3. 讀取網頁時，用 stream，不要用 WebClient！

使用 WebClient 來讀取網頁，得到的並非是 raw data，而是已被 default encoding 轉換過的 data。更進一步解釋，就是使用了 UTF8 –> Unicode 轉換表來轉換 BIG5 的資料，這會導致資料整個變成不可用的亂碼。

 

實作

將 BIG5.TXT 加入專案

 

 

在 ContentPanel 加入一個 textBlock

 

MainPage.xaml.cs

using System;

using System.Collections.Generic;

using System.Linq;

using System.Net;

using System.Windows;

using System.Windows.Controls;

using System.Windows.Documents;

using System.Windows.Input;

using System.Windows.Media;

using System.Windows.Media.Animation;

using System.Windows.Shapes;

using Microsoft.Phone.Controls;

using System.IO;

using System.Globalization;

using System.Diagnostics;

using System.Text;

namespace PhoneApp2

{

    public partial class MainPage : PhoneApplicationPage

    {

        // async http

        delegate void DownDelegate(string content);

        DownDelegate downDelegate;

        // Big5 to Unicode mapping table

        private static Dictionary<int, int> mBIG5_Unicode_MAP = new Dictionary<int, int>();

        // 建構函式

        public MainPage()

        {

            InitializeComponent();

            createBig5ToUnicodeDictionary();

            readBig5WebPage();

        }

        private void setConent(string content)

        {

            textBlock1.Text = content;

        }

        private void createBig5ToUnicodeDictionary()

        {

            var resource = Application.GetResourceStream(new Uri("BIG5.TXT", UriKind.Relative));

            StreamReader sr = new StreamReader(resource.Stream);

            string line;

            while ((line = sr.ReadLine()) != null)

            {

                // 忽略註解

                if (line.StartsWith("#")) continue;

                string[] lTokens = line.Split(new char[] {'\t'});

                mBIG5_Unicode_MAP.Add(hexToInt(lTokens[0].Substring(2)), hexToInt(lTokens[1].Substring(2)));

            }

        }

        private void readBig5WebPage()

        {

            textBlock1.Text = "讀取中...";

            string url = "http://www.businessweekly.com.tw/feednews.php";

            downDelegate = setConent;

            System.Net.WebRequest request = HttpWebRequest.Create(url);

            IAsyncResult result = request.BeginGetResponse(ResponseCallback, request);

        }

        private void ResponseCallback(IAsyncResult result)

        {

            HttpWebRequest request = (HttpWebRequest)result.AsyncState;

            WebResponse response = request.EndGetResponse(result);

            Stream s = response.GetResponseStream();

            Dispatcher.BeginInvoke(downDelegate, big5ToUnicode(s).ToString());

        }

        private StringBuilder big5ToUnicode(Stream s)

        {

            StringBuilder lSB = new StringBuilder();

            byte[] big5Buffer = new byte[2];

            int input;

            while ((input = s.ReadByte()) != -1)

            {

                if (input > 0x81 && big5Buffer[0] == 0)

                {

                    big5Buffer[0] = (byte)input;

                }

                else if (big5Buffer[0] != 0)

                {

                    big5Buffer[1] = (byte)input;

                    int Big5Char = (big5Buffer[0] << 8) + big5Buffer[1];

                    try

                    {

                        int UTF8Char = mBIG5_Unicode_MAP[Big5Char];

                        lSB.Append((char)UTF8Char);

                    }

                    catch (Exception)

                    {

                        lSB.Append((char)mBIG5_Unicode_MAP[0xA148]);

                    }

                    big5Buffer = new byte[2];

                }

                else

                {

                    lSB.Append((char)input);

                }

            }

            return lSB;

        }

        private int hexToInt(string hexString)

        {

            return int.Parse(hexString, NumberStyles.HexNumber);

        }

    }

}

 

範例程式碼下載

 

參考連結

• http://forums.create.msdn.com/forums/p/73736/553266.aspx
• http://www.pocketdigi.com/20120315/702.html