Autofac是一款IOC框架,比较于其他的IOC框架,如Spring.NET,Unity,Castle等等所包含的,它很轻量级性能上也是很高的。于是,今天抽空研究了下它。下载地址:http://code.google.com/p/autofac/downloads/list
1)解压它的压缩包,主要看到Autofac.dll,Autofac.Configuration.dll,这也是本篇文章重点使用的Autofac的类库。
2)创建一个控制台工程,并且引用以上的DLL文件。创建一个数据库操作接口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);
}
这里包含CRUD四种操作的方法。
3)创建两种数据库的操作类,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)接着创建一个数据库管理器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,编写以下测试程序:
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");
}
运行结果:
分析:
这里通过ContainerBuilder方法RegisterType对DatabaseManager进行注册,当注册的类型在相应得到的容器中可以Resolve你的DatabaseManager实例。
builder.RegisterType<SqlDatabase>().As<IDatabase>();通过AS可以让DatabaseManager类中通过构造函数依赖注入类型相应的接口。
Build()方法生成一个对应的Container实例,这样,就可以通过Resolve解析到注册的类型实例。
同样地,如果你修改数据库类型注册为:
builder.RegisterType<OracleDatabase>().As<IDatabase>();
运行结果:
6)显然以上的程序中,SqlDatabase或者OracleDatabase已经暴露于客户程序中了,现在我想将该类型选择通过文件配置进行读取。Autofac自带了一个Autofac.Configuration.dll 非常方便地对类型进行配置,避免了程序的重新编译。
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>
通过Autofac.Configuration.SectionHandler配置节点对组件进行处理。
对应的客户端程序改为:
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");
}
运行结果:
7)另外还有一种方式,通过Register方法进行注册:
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");
}
得到结果也是一样的。
8)现在我想通过一个用户类来控制操作权限,比如增删改的权限,创建一个用户类:
/// <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代码:
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);
}
}
在构造函数中增加了一个参数User,而Add,Save,Remove增加了权限判断。
修改客户端程序:
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 ...");
}
运行结果:
分析:
builder.RegisterInstance(user).As<User>();注册User实例。
builder.Register(c => new DatabaseManager(c.Resolve<IDatabase>(), c.Resolve<User>()));通过Lampda表达式注册DatabaseManager实例。
如果这里我修改User的属性值:
User user = new User { Id = 2, Name = "zhangsan" };
运行结果:
说明该用户无权限操作。
源代码下载:AutofacDemo.rar