通過因特網(wǎng)產(chǎn)生許多服務(wù)請求可能影響客戶應(yīng)用程序的性能。當(dāng)設(shè)計(jì)你的XML Web服務(wù)時(shí)，通過創(chuàng)建把有關(guān)信息集中在一起的方法可以有效利用服務(wù)請求。例如，假定你有一個(gè)XML Web服務(wù)，用來檢索一本書的信息。我們可以創(chuàng)建一個(gè)在一條服務(wù)請求中返回所有的信息的方法，來代替單獨(dú)的檢索書名、作者和出版社的方法。一次傳送大塊的信息比多次傳送小塊的信息更有效率。
下面的代碼示例解釋如何把有關(guān)信息組織到單個(gè)XML Web服務(wù)方法中。 [C#]
＜%@ WebService Language="C#" Class="DataService" %＞
using System;
using System.Data;
using System.Data.SqlClient;
using System.Web.Services;
public class DataService {
[WebMethod]
public DataSet GetTitleAuthors() {
SqlConnection myConnection = new SqlConnection("Persist Security Info=False;Integrated Security=SSPI;server=localhost;database=pubs");
SqlDataAdapter myCommand1 = new SqlDataAdapter ("select * from Authors", myConnection);
SqlDataAdapter myCommand2 = new SqlDataAdapter("select * from Titles", myConnection);
DataSet ds = new DataSet();
myCommand1.Fill(ds, "Authors");
myCommand2.Fill(ds, "Titles");
return ds;
}
}
[Visual Basic]
＜%@ WebService Language="VB" Class="DataService" %＞
Imports System
Imports System.Data
Imports System.Data.SqlClient
Imports System.Web.Services
Public Class DataService
＜WebMethod＞ _
Public Function GetTitleAuthors() As DataSet
Dim myConnection As New SqlConnection("Persist Security Info=False;Integrated Security=SSPI;server=localhost;database=pubs")
Dim myCommand1 As New SqlDataAdapter("select * from Authors", myConnection)
Dim myCommand2 As New SqlDataAdapter("select * from Titles", myConnection)
Dim ds As New DataSet()
myCommand1.Fill(ds, "Authors")
myCommand2.Fill(ds, "Titles")
Return ds
End Function
End Class |
當(dāng)設(shè)計(jì)你的XML Web服務(wù)時(shí)，請確保使用標(biāo)準(zhǔn)的面向?qū)ο缶幊滩僮鳌Ｊ褂梅庋b來隱藏實(shí)現(xiàn)細(xì)節(jié)。對于更復(fù)雜的XML Web服務(wù)，你可以使用繼承和多態(tài)性來再次使用代碼并簡化你的設(shè)計(jì)。
下面的代碼示例顯示如何使用繼承來創(chuàng)建一個(gè)執(zhí)行數(shù)學(xué)計(jì)算的XML Web服務(wù)。
[C#]
＜%@ WebService Language="C#" Class="Add" %＞
using System;
using System.Web.Services;
abstract public class MathService : WebService
{
[WebMethod]
abstract public float CalculateTotal(float a, float b);
}
public class Add : MathService
{
[WebMethod]
override public float CalculateTotal(float a, float b)
{
return a + b;
}
}
public class Subtract : MathService
{
[WebMethod]
override public float CalculateTotal(float a, float b)
{
return a - b;
}
}
public class Multiply : MathService
{
[WebMethod]
override public float CalculateTotal(float a, float b)
{
return a * b;
}
}
public class Divide : MathService
{
[WebMethod]
override public float CalculateTotal(float a, float b)
{
if (b==0)
return -1;
else
return a / b;
}
}
[Visual Basic]
＜%@ WebService Language="VB" Class="Add" %＞
Imports System
Imports System.Web.Services
MustInherit Public Class MathService : Inherits WebService
＜WebMethod＞ _
Public MustOverride Function CalculateTotal(a As Single, _
b As Single) As Single
End Class
Public Class Add : Inherits MathService
＜WebMethod＞ Public Overrides Function CalculateTotal(a As Single, b As Single) As Single
Return a + b
End Function
End Class
Public Class Subtract : Inherits MathService
＜WebMethod＞ Public Overrides Function CalculateTotal(a As Single, b As Single) As Single
Return a - b
End Function
End Class
Public Class Multiply : Inherits MathService
＜WebMethod＞ Public Overrides Function CalculateTotal(a As Single, b As Single) As Single
Return a * b
End Function
End Class
Public Class Divide : Inherits MathService
＜WebMethod＞ Public Overrides Function CalculateTotal(a As Single, b As Single) As Single
If b = 0 Then
Return - 1
Else
Return a / b
End If
End Function
End Class |
