淺談WebService開發(一)轉
一、什麽是WebService:
簡單通俗來說,就是企業之間、網站之間通過Internet來訪問並使用在線服務,一些數據,由於安全性問題,不能提供數據庫給其他單位使用,這時候可以使 用WebService服務提供。
二、創建WebService
創建WebService之後,我們就可以在文件裏寫返回數據的方法了。
三、返回數據的四種形式
筆者水平有限,只列出這四種數據的返回形式:
(1)直接返回DataSet對象
(2)返回DataSet對象用Binary序列化後的字節數組
(3)返回DataSetSurrogate對象用Binary序列化後的 字節數組
(4)返回DataSetSurrogate對象用Binary序列化並Zip 壓縮後的字節數組
理論上來說,網絡傳輸字節與傳輸時間,應該是遞減的,其中,(3)(4)種方法需要引用微軟提供的開源組件 下載地址:http://support.microsoft.com/kb/829740/zh-cn
下面展示這四種返回數據的代碼,其中(1)是其三種方法的根本,都要得到一個DataSet作為根本,然後來做各種轉換壓縮的操作:
[WebMethod(Description = "直接返回DataSet對象")] public DataSet GetDataSet() { string connStr = System.Configuration.ConfigurationManager.ConnectionStrings["conn"].ToString(); SqlConnection conn = new SqlConnection(connStr); string sql = "select * from china_city"; conn.Open(); SqlDataAdapter sda = new SqlDataAdapter(sql, conn); DataSet ds = new DataSet("China"); sda.Fill(ds); conn.Close();return ds; } [WebMethod(Description = "直接返回DataSet對象,並用Binary序列化後的字節數組")] public byte[] GetDataSetBytes() { DataSet ds = GetDataSet(); BinaryFormatter ser = new BinaryFormatter(); //序列化對象 MemoryStream ms = new MemoryStream(); //內存流 ser.Serialize(ms, ds); byte[] buffer = ms.ToArray(); //字節流 return buffer; } [WebMethod(Description = "直接返回DataSetSurrogate對象,並用Binary序列化後的字節數組")] public byte[] GetDataSetSurrogateBytes() { DataSet ds = GetDataSet(); DataSetSurrogate dss = new DataSetSurrogate(ds); BinaryFormatter ser = new BinaryFormatter(); //序列化對象 MemoryStream ms = new MemoryStream(); //內存流 ser.Serialize(ms, dss); byte[] buffer = ms.ToArray(); //字節流 return buffer; } [WebMethod(Description = "直接返回DataSetSurrogate對象,並用Binary序列化後並且ZIP壓縮的字節數組")] public byte[] GetDataSetSurrogateZipBytes() { DataSet ds = GetDataSet(); DataSetSurrogate dss = new DataSetSurrogate(ds); BinaryFormatter ser = new BinaryFormatter(); //序列化對象 MemoryStream ms = new MemoryStream(); //內存流 ser.Serialize(ms, dss); byte[] buffer = ms.ToArray(); //字節流 byte[] bufferZip = ComPress(buffer); return buffer; } //壓縮方法 public byte[] ComPress(byte[] data) { try { MemoryStream ms = new MemoryStream(); Stream zipStream = null; zipStream = new GZipStream(ms, CompressionMode.Compress, true); zipStream.Write(data, 0, data.Length); zipStream.Close(); ms.Position = 0; byte[] compressed_data = new byte[ms.Length]; ms.Read(compressed_data, 0, int.Parse(ms.Length.ToString())); return compressed_data; } catch { return null; } }
我們可以在瀏覽器中查看下WebService的效果,如圖,在這個頁面中,有提供四個方法,這四個方法就是上述我們寫的四個返回數據的方法了,點擊方法即可返回相應的數據,這樣,我們數據提供方的代碼就可以寫好了,接下來,我們寫調用數據的方法!
四、調用數據
客戶端WebService程序
private void button1_Click(object sender, EventArgs e) { com.dzbsoft.www.Service1 ds = new com.dzbsoft.www.Service1(); //new出WebService對象 DateTime dtBegin = DateTime.Now; DataSet dataSet = ds.GetNorthwindDataSet(); this.label1.Text = string.Format("耗時:{0}", DateTime.Now - dtBegin); binddata(dataSet); } private void button2_Click(object sender, EventArgs e) { com.dzbsoft.www.Service1 ds = new com.dzbsoft.www.Service1(); DateTime dtBegin = DateTime.Now; byte[] buffer = ds.GetDataSetBytes(); BinaryFormatter ser = new BinaryFormatter(); DataSet dataSet = ser.Deserialize(new MemoryStream(buffer)) as DataSet; this.label2.Text = string.Format("耗時:{0}", DateTime.Now - dtBegin) + " " + buffer.Length; binddata(dataSet); } private void button3_Click(object sender, EventArgs e) { com.dzbsoft.www.Service1 ds = new com.dzbsoft.www.Service1(); DateTime dtBegin = DateTime.Now; byte[] buffer = ds.GetDataSetSurrogateBytes(); BinaryFormatter ser = new BinaryFormatter(); DataSetSurrogate dss = ser.Deserialize(new MemoryStream(buffer)) as DataSetSurrogate; DataSet dataSet = dss.ConvertToDataSet(); this.label3.Text = string.Format("耗時:{0}", DateTime.Now - dtBegin) + " " + buffer.Length; binddata(dataSet); } private void button4_Click(object sender, EventArgs e) { com.dzbsoft.www.Service1 ds = new com.dzbsoft.www.Service1(); DateTime dtBegin = DateTime.Now; byte[] zipBuffer = ds.GetDataSetSurrogateZipBytes(); byte[] buffer = UnZipClass.Decompress(zipBuffer); BinaryFormatter ser = new BinaryFormatter(); DataSetSurrogate dss = ser.Deserialize(new MemoryStream(buffer)) as DataSetSurrogate; DataSet dataSet = dss.ConvertToDataSet(); this.label4.Text = string.Format("耗時:{0}", DateTime.Now - dtBegin) + " " + zipBuffer.Length; binddata(dataSet); } private void binddata(DataSet dataSet) { this.dataGridView1.DataSource = dataSet.Tables[0]; this.label5.Text = "共計:" + dataSet.Tables[0].Rows.Count + "條記錄"; }
在數據返回的方法中,我們使用了數據的壓縮,所以,在調用方這邊,需要進行解壓,代碼:
客戶端UnZipClass程序 public static class UnZipClass { public static byte[] Decompress(byte[] data) { try { MemoryStream ms = new MemoryStream(data); Stream zipStream = null; zipStream = new GZipStream(ms, CompressionMode.Decompress); byte[] dc_data = null; dc_data = ExtractBytesFromStream(zipStream, data.Length); return dc_data; } catch { return null; } } public static byte[] ExtractBytesFromStream(Stream zipStream, int dataBlock) { byte[] data = null; int totalBytesRead = 0; try { while (true) { Array.Resize(ref data, totalBytesRead + dataBlock + 1); int bytesRead = zipStream.Read(data, totalBytesRead, dataBlock); if (bytesRead == 0) { break; } totalBytesRead += bytesRead; } Array.Resize(ref data, totalBytesRead); return data; } catch { return null; } } }
在上例中,調用四個方法的效果是一樣的,唯一不同的是,傳輸過程中,數據量大小和傳輸時間的差異。
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淺談WebService開發(一)轉