依賴注入架構Autofac的簡單使用
Autofac是一款IOC架構,比較于其他的IOC架構,如Spring.NET,Unity,Castle等等所包含的,它很輕量級性能上也是很高的。于是,今天抽空研究了下它。下載下傳位址:http://code.google.com/p/autofac/downloads/list
1)解壓它的壓縮包,主要看到Autofac.dll,Autofac.Configuration.dll,這也是本篇文章重點使用的Autofac的類庫。
2)建立一個控制台工程,并且引用以上的DLL檔案。建立一個資料庫操作接口IDatabase.cs:
///
<summary>
///
Database operate interface
///
</summary>
public
interface
IDatabase
{
string
Name {
get
; }
void
Select(
string
commandText);
void
Insert(
string
commandText);
void
Update(
string
commandText);
void
Delete(
string
commandText);
}
這裡包含CRUD四種操作的方法。
3)建立兩種資料庫的操作類,SqlDatabase.cs以及OracleDatabase.cs:
public
class
SqlDatabase : IDatabase
{
public
string
Name
{
get
{
return
"
sqlserver
"
; }
}
public
void
Select(
string
commandText)
{
Console.WriteLine(
string
.Format(
"
'{0}' is a query sql in {1}!
"
, commandText, Name));
}
public
void
Insert(
string
commandText)
{
Console.WriteLine(
string
.Format(
"
'{0}' is a insert sql in {1}!
"
, commandText, Name));
}
public
void
Update(
string
commandText)
{
Console.WriteLine(
string
.Format(
"
'{0}' is a update sql in {1}!
"
, commandText, Name));
}
public
void
Delete(
string
commandText)
{
Console.WriteLine(
string
.Format(
"
'{0}' is a delete sql in {1}!
"
, commandText, Name));
}
}
以及
public
class
OracleDatabase : IDatabase
{
public
string
Name
{
get
{
return
"
oracle
"
; }
}
public
void
Select(
string
commandText)
{
Console.WriteLine(
string
.Format(
"
'{0}' is a query sql in {1}!
"
, commandText, Name));
}
public
void
Insert(
string
commandText)
{
Console.WriteLine(
string
.Format(
"
'{0}' is a insert sql in {1}!
"
, commandText, Name));
}
public
void
Update(
string
commandText)
{
Console.WriteLine(
string
.Format(
"
'{0}' is a update sql in {1}!
"
, commandText, Name));
}
public
void
Delete(
string
commandText)
{
Console.WriteLine(
string
.Format(
"
'{0}' is a delete sql in {1}!
"
, commandText, Name));
}
}
4)接着建立一個資料庫管理器DatabaseManager.cs:
public
class
DatabaseManager
{
IDatabase _database;
public
DatabaseManager(IDatabase database)
{
_database
=
database;
}
public
void
Search(
string
commandText)
{
_database.Select(commandText);
}
public
void
Add(
string
commandText)
{
_database.Insert(commandText);
}
public
void
Save(
string
commandText)
{
_database.Update(commandText);
}
public
void
Remove(
string
commandText)
{
_database.Delete(commandText);
}
}
5)在控制台中,編寫以下測試程式:
var builder
=
new
ContainerBuilder();
builder.RegisterType
<
DatabaseManager
>
();
builder.RegisterType
<
SqlDatabase
>
().As
<
IDatabase
>
();
using
(var container
=
builder.Build())
{
var manager
=
container.Resolve
<
DatabaseManager
>
();
manager.Search(
"
SELECT * FORM USER
"
);
}
運作結果:
分析:
這裡通過ContainerBuilder方法RegisterType對DatabaseManager進行注冊,當注冊的類型在相應得到的容器中可以Resolve你的DatabaseManager執行個體。
builder.RegisterType<SqlDatabase>().As<IDatabase>();通過AS可以讓DatabaseManager類中通過構造函數依賴注入類型相應的接口。
Build()方法生成一個對應的Container執行個體,這樣,就可以通過Resolve解析到注冊的類型執行個體。
同樣地,如果你修改資料庫類型注冊為:
builder.RegisterType<OracleDatabase>().As<IDatabase>();
運作結果:
6)顯然以上的程式中,SqlDatabase或者OracleDatabase已經暴露于客戶程式中了,現在我想将該類型選擇通過檔案配置進行讀取。Autofac自帶了一個Autofac.Configuration.dll 非常友善地對類型進行配置,避免了程式的重新編譯。
修改App.config:
<
configuration
>
<
configSections
>
<
section
name
="autofac"
type
="Autofac.Configuration.SectionHandler, Autofac.Configuration"
/>
</
configSections
>
<
autofac
defaultAssembly
="AutofacDemo"
>
<
components
>
<
component
type
="AutofacDemo.SqlDatabase, AutofacDemo"
service
="AutofacDemo.IDatabase"
/>
</
components
>
</
autofac
>
</
configuration
>
通過Autofac.Configuration.SectionHandler配置節點對元件進行處理。
對應的用戶端程式改為:
var builder
=
new
ContainerBuilder();
builder.RegisterType
<
DatabaseManager
>
();
builder.RegisterModule(
new
ConfigurationSettingsReader(
"
autofac
"
));
using
(var container
=
builder.Build())
{
var manager
=
container.Resolve
<
DatabaseManager
>
();
manager.Search(
"
SELECT * FORM USER
"
);
}
運作結果:
7)另外還有一種方式,通過Register方法進行注冊:
var builder
=
new
ContainerBuilder();
//
builder.RegisterType<DatabaseManager>();
builder.RegisterModule(
new
ConfigurationSettingsReader(
"
autofac
"
));
builder.Register(c
=>
new
DatabaseManager(c.Resolve
<
IDatabase
>
()));
using
(var container
=
builder.Build())
{
var manager
=
container.Resolve
<
DatabaseManager
>
();
manager.Search(
"
SELECT * FORM USER
"
);
}
得到結果也是一樣的。
8)現在我想通過一個使用者類來控制操作權限,比如增删改的權限,建立一個使用者類:
///
<summary>
///
Id Identity Interface
///
</summary>
public
interface
Identity
{
int
Id {
get
;
set
; }
}
public
class
User : Identity
{
public
int
Id {
get
;
set
; }
public
string
Name {
get
;
set
; }
}
修改DatabaseManager.cs代碼:
public
class
DatabaseManager
{
IDatabase _database;
User _user;
public
DatabaseManager(IDatabase database) :
this
(database,
null
)
{
}
public
DatabaseManager(IDatabase database, User user)
{
_database
=
database;
_user
=
user;
}
///
<summary>
///
Check Authority
///
</summary>
///
<returns></returns>
public
bool
IsAuthority()
{
bool
result
=
_user
!=
null
&&
_user.Id
==
1
&&
_user.Name
==
"
leepy
"
?
true
:
false
;
if
(
!
result)
Console.WriteLine(
"
Not authority!
"
);
return
result;
}
public
void
Search(
string
commandText)
{
_database.Select(commandText);
}
public
void
Add(
string
commandText)
{
if
(IsAuthority())
_database.Insert(commandText);
}
public
void
Save(
string
commandText)
{
if
(IsAuthority())
_database.Update(commandText);
}
public
void
Remove(
string
commandText)
{
if
(IsAuthority())
_database.Delete(commandText);
}
}
在構造函數中增加了一個參數User,而Add,Save,Remove增加了權限判斷。
修改用戶端程式:
User user
=
new
User { Id
=
1
, Name
=
"
leepy
"
};
var builder
=
new
ContainerBuilder();
builder.RegisterModule(
new
ConfigurationSettingsReader(
"
autofac
"
));
builder.RegisterInstance(user).As
<
User
>
();
builder.Register(c
=>
new
DatabaseManager(c.Resolve
<
IDatabase
>
(), c.Resolve
<
User
>
()));
using
(var container
=
builder.Build())
{
var manager
=
container.Resolve
<
DatabaseManager
>
();
manager.Add(
"
INSERT INTO USER ...
"
);
}
運作結果:
分析:
builder.RegisterInstance(user).As<User>();注冊User執行個體。
builder.Register(c => new DatabaseManager(c.Resolve<IDatabase>(), c.Resolve<User>()));通過Lampda表達式注冊DatabaseManager執行個體。
如果這裡我修改User的屬性值:
User user = new User { Id = 2, Name = "zhangsan" };
運作結果: