DotNet企业级架构实战之5——基于接口的访问层实现

前几节的内容比较务虚，这一节主要讲讲怎么应用Spring.net和nHibernate及我们写的模板，来搭建一个数据访问层，以及在页面中的调用。

　　先来看一个层级图：

　　


　　这里有一个model（实体）层，一个DAO（数据访问）层，中间还有一个Interface（接口）层。

　　这又回到了最初的探索：接口的做用，一是隐藏实现的细节;二是更利于装配——在spring.net的配置文件中，你可以随时装配一个不同的实现，只要它完成接口规定的方法，好处不言而喻——于页面而言，它并不知道谁来实现了这些功能，它只知道接口的存在（你们都去实现接口吧，我不关心谁在做这件事，要的只是结果！）

　　◆欧克，现在页面需要一个对用户表访问的东西（TB_USER_MAIN表，对应的实体是woodigg.model.USERMAIN），先做一个接口，在woodigg.Interface层添加一个接口：　　





Code

using
System;

using
System.Collections.Generic;

using
System.Text;

using
System.Data;

using
woodigg.model;

namespace
woodigg.Interface.DAO

{

///

<summary>

///
user main DAO Interface

///

</summary>

public

interface
IUserMainDAO

{

///

<summary>

///
存

///

</summary>

bool
Save(USERMAIN mb);

///

<summary>

///
事务级添加

///

</summary>

///

<param name="art"></param>

///

<param name="from"></param>

///

<returns></returns>

bool
TransactionSave(USERMAIN art,
string
from);

///

<summary>

///
更新

///

</summary>

bool
Update(USERMAIN mb);

///

<summary>

///
事务级删除

///

</summary>

bool
Delete(USERMAIN mb);

///

<summary>

///
读

///

</summary>

USERMAIN LoadFromId(
int
id);

///

<summary>

///
搜索

///

</summary>

IList
<
USERMAIN
>
SearchByWhere(
string

where
);

///

<summary>

///
搜索排序

///

</summary>

IList
<
USERMAIN
>
SearchByWhereOrder(
string

where
,
string
propertyName,
bool
ascending);

///

<summary>

///
分页

///

</summary>

DataTable GetPagerByStoreProc(
string
Columns,
int
pageSize,
int
pageIdx

,
string
OrderColumn,
bool
orderType,
string
condition);

///

<summary>

///
获取记录数

///

</summary>

int
GetRecordCount(
string

where
);

}

}

　　◆显然，它的功能都是上一节那个DaoTemplate泛型模板已经有的，要实现真的很easy——编译刚才的woodigg.Interface项目，并在woodigg.DAO层中引用此项目，然后添加一个实现：





Code

using
System;

using
System.Collections.Generic;

using
System.Text;

using
System.Data;

using
Spring.Context;

using
Spring.Context.Support;

using
Spring.Dao;

using
Spring.Data.NHibernate.Support;

using
woodigg.model;

using
woodigg.Interface.DAO;

using
Spring.Transaction.Interceptor;

namespace
woodigg.DAO

{

///

<summary>

///
user main DAO

///

</summary>

public

class
UserMainDaoSpring : IUserMainDAO

{

#region
注入的DaoTemplate

private
DaoTemplate _DaoTemplate;

public
DaoTemplate DaoTemplate

{

get
{
return
_DaoTemplate; }

set
{ _DaoTemplate
=
value; }

}

#endregion

private

const

string
TableName
=

"
TB_USER_MAIN
"
;
//
表名

private

const

string
PrimaryKey
=

"
Id
"
;
//
主键

public
UserMainDaoSpring() { }

///

<summary>

///
存

///

</summary>

public

bool
Save(USERMAIN art)

{

return
DaoTemplate.Save
<
USERMAIN
>
(art);

}

///

<summary>

///
事务级添加

///

</summary>

///

<param name="art"></param>

///

<param name="from">
从哪来
</param>

///

<returns></returns>

[Transaction()]

public

bool
TransactionSave(USERMAIN art,
string
from)

{

if
(DaoTemplate.Save
<
USERMAIN
>
(art))

{

USEROTHER ot
=

new
USEROTHER();

ot.UserId
=
art.Id;

ot.UserFrom
=
from;

return
DaoTemplate.Save
<
USEROTHER
>
(ot);

}

else

return

false
;

}

///

<summary>

///
更新

///

</summary>

///

<param name="art"></param>

///

<returns></returns>

public

bool
Update(USERMAIN art)

{

return
DaoTemplate.Update
<
USERMAIN
>
(art);

}

///

<summary>

///
删除

///

</summary>

///

<param name="art"></param>

[Transaction()]

public

bool
Delete(USERMAIN art)

{

DaoTemplate.Delete
<
USEROTHER
>
(
"
UserId=
"

+
art.Id);

return
DaoTemplate.Delete
<
USERMAIN
>
(art);

}

///

<summary>

///
读

///

</summary>

public
USERMAIN LoadFromId(
int
id)

{

return
DaoTemplate.LoadFromId
<
USERMAIN
>
(id);

}

///

<summary>

///
查

///

</summary>

public
IList
<
USERMAIN
>
SearchByWhere(
string

where
)

{

return
DaoTemplate.Search
<
USERMAIN
>
(
where
);

}

///

<summary>

///
查排序

///

</summary>

public
IList
<
USERMAIN
>
SearchByWhereOrder(
string

where
,
string
propertyName,
bool
ascending)

{

return
DaoTemplate.SearchWithOrder
<
USERMAIN
>
(
where
,propertyName,ascending);

}

///

<summary>

///
分页

///

</summary>

///

<param name="pageSize"></param>

///

<param name="pageIdx"></param>

///

<param name="OrderColumn"></param>

///

<param name="orderType"></param>

///

<param name="condition"></param>

///

<returns></returns>

public
DataTable GetPagerByStoreProc(
string
Columns,
int
pageSize,
int
pageIdx

,
string
OrderColumn,
bool
orderType,
string
condition)

{

return
DaoTemplate.GetPageEntitesByStoredProc

(TableName, PrimaryKey, Columns, OrderColumn, pageSize, pageIdx, orderType, condition);

}

///

<summary>

///
获取记录数

///

</summary>

///

<param name="where"></param>

public

int
GetRecordCount(
string

where
) {

return
DaoTemplate.GetRecordCount
<
USERMAIN
>
(
where
);

}

}

}

　　◆为这种类型的DAL制作一个配置文件business.xml，以便在需要时，由spring.net的对象工厂实例化并派发它：





Code

<?
xml version="1.0" encoding="utf-8"
?>

<
objects
xmlns
="http://www.springframework.net"

xmlns:xsi
="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation
="http://www.springframework.net http://www.springframework.net/xsd/spring-objects.xsd"
>

<
object
id
="UserMainDaoSpring"
type
="woodigg.DAO.UserMainDaoSpring,woodigg.DAO"
autowire
="byName"

/>

</
objects
>

　　◆至此，一个所谓的DAL打造完成，把它应用到.aspx页面中去（当然，实例中比这复杂得多，以后我们会在ASP.NET MVC中应用这些，页面只是个壳）。为了.aspx页面，做一个配置文件pageConfig.xml吧，在这个xml里，登记所有需要注入的页面路径，以便植入实现了接口的DAL：



　　假设这页面在/下，叫test.aspx：





Code

<?
xml version="1.0" encoding="utf-8"
?>

<
objects
xmlns
="http://www.springframework.net"

xmlns:xsi
="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation
="http://www.springframework.net http://www.springframework.net/xsd/spring-objects.xsd"
>

<!--
页面调用
-->

<
object
type
="~/test.aspx"
autowire
="byName"

/>

</
objects
>

　　如前所述，byName的意思是：页面上写什么接口，就自动去配置环境中查找相应接口实现，并把它在工厂中的实例注入页面中。

　　◆然后，我们整合一下应用环境，把它配置到web.config中：





Code

<
configSections
>

<
sectionGroup
name
="spring"
>

<
section
name
="context"
type
="Spring.Context.Support.WebContextHandler, Spring.Web"
/>

<
section
name
="objects"
type
="Spring.Context.Support.DefaultSectionHandler, Spring.Core"
/>

</
sectionGroup
>

<
section
name
="SpringOverrideProperty"
type
="System.Configuration.NameValueSectionHandler"
/>

<
section
name
="nhibernate"
type
="System.Configuration.NameValueSectionHandler, System, Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
/>

<!--
log4net
-->

<
section
name
="log4net"
type
="log4net.Config.Log4NetConfigurationSectionHandler,log4net"
/>

</
configSections
>

<
SpringOverrideProperty
>

<
add
key
="DbProvider.ConnectionString"
value
="Data Source=(local);Database=Music;User ID=sa;Password=system;Trusted_Connection=False"
/>

<
add
key
="SystemInit.IsDebug"
value
="true"
/>

<
add
key
="SystemInit.Level"
value
="4"
/>

</
SpringOverrideProperty
>

<!--
Spirng.Net 配置
-->

<
spring
>

<
context
>

<
resource
uri
="config://spring/objects"
/>

<
resource
uri
="~/config/applicationContext.xml"
/>

<
resource
uri
="~/config/business.xml"
/>

<
resource
uri
="~/config/pageConfig.xml"
/>

</
context
>

<
objects
xmlns
="http://www.springframework.net"
/>

</
spring
>

<
system.web
>

<
httpModules
>

<
add
name
="Spring"
type
="Spring.Context.Support.WebSupportModule, Spring.Web"
/>

</
httpModules
>

<
httpHandlers
>

<
add
verb
="*"
path
="*.aspx"
type
="Spring.Web.Support.PageHandlerFactory, Spring.Web"
/>

</
system.web
>

</
httpHandlers
>

</
system.web
>

　　◆最后，test.aspx.cs中，这样引用前面基于IUserMainDAO接口的实现，就能让它跑起来了：





Code

#region
注入对象

private
IUserMainDAO _UserMainDaoSpring;

public
IUserMainDAO UserMainDaoSpring

{

get
{
return
_UserMainDaoSpring; }

set
{ _UserMainDaoSpring
=
value; }

}

#endregion

　　看起来，似乎是繁琐到发指的一些工作，不过形成习惯了应该就会喜欢上它的，眼下的麻烦只是为了避免未来更大的麻烦，图难图其易图巨图其细嘛~