Spring.Net学习系列一（续）：日志处理
本文接着上篇：Spring.Net学习系列一： 统一异常处理继续学习Spring.Net的AOP。
在这篇中，将利用前置通知(BeforeAdvice),通过.net的Attribute特性来实现日志处理。
在上一篇中，我们通过ProxyFactoryObject显式创建AOP代理的方法。如果应用程序需要创建很多AOP代理，比如当需要代理某个服务层或者数据访问层的所有对象时，这种方法就会使配置文件变的相当庞大。为简化配置过程，Spring.NET提供了“自动代理”的功能，可以根据条件自动创建代理对象，也就是说，可以将多个对象分组以作为要代理的候选对象。在本文中，将使用ObjectNameAutoProxyCreator进行自动代理。ObjectNameAutoProxyCreator可以用特定的文本值或通配符匹配目标对象的名称，并为满足条件的目标对象创建AOP代理。该类支持模式匹配字符串，如："*name"，"name*"，”*name*“和精确文本如"name"。
注：这里的ObjectName即为配置文件中objects节点下的一系列的object的名称
首先创建前置通知的具体实现：
代码
using System;
using System.Collections.Generic;
using System.Text;
using Spring.Aop;
using System.Web;
namespace Log
{
public class BeforeAdvice : IMethodBeforeAdvice
{
private Log logInstance;
public BeforeAdvice()
{
logInstance = Log.GetInstance();
}
public void Before(System.Reflection.MethodInfo method, object[] args, object target)
{
Type dao = target.GetType();
Object[] attributes = dao.GetMethod(method.Name).GetCustomAttributes(true);
OperationAttribute attribute = null;
foreach (object obj in attributes)
{
if (obj is OperationAttribute)
{
attribute = obj as OperationAttribute;
break;
}
}
if (attribute != null)
{
User user = HttpContext.Current.Session["user"] as User;
string strLogInfo = string.Format("UserName:{0} ,OperationTime:{1},OperationType:{2},OperatedTarget:{3},Method:{4},Argument:{5}",
user.UserName, DateTime.Now, attribute.Op, target, method,ArrayToString(args));
logInstance.Info(strLogInfo);
}
}
private string ArrayToString(object[] args)
{
if (args == null || args.Length == 0) return "NULL";
string str = "";
foreach (object o in args)
{
str += o.ToString()+"|";//在实体类中，需要重写ToString方法,以获得更好效果
}
return str.TrimEnd(new char[]{'|'});
}
}
}
接下来模拟一个数据访问层IUserDao和实现类
代码
using System;
using System.Collections.Generic;
using System.Text;
namespace Log
{
public interface IUserDao
{
IList<User> GetUserByName(string userName,string password);
void SaveUser(User u);
void UpdateUser(User u);
void DeleteUser(User u);
}
}
代码
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Log
{
public class UserDao:IUserDao
{
#region IUserDao 成员
[Operation(OperationEnum.Select)]
public IList<User> GetUserByName(string userName,string password)
{
return null;
}
[Operation(OperationEnum.Insert)]
public void SaveUser(User u)
{
}
[Operation(OperationEnum.Update)]
public void UpdateUser(User u)
{
}
[Operation(OperationEnum.Delete)]
public void DeleteUser(User u)
{
}
#endregion
}
}
注意在UserDao实现类中已经加入了OperationAttribute。
OperationAttribute的代码如下：
代码
using System;
using System.Collections.Generic;
using System.Text;
namespace Log
{
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method | AttributeTargets.Property, Inherited = true)]
public class OperationAttribute:Attribute
{
private OperationEnum op;
public OperationAttribute(OperationEnum op)
{
this.op = op;
}
public OperationEnum Op
{
get { return this.op; }
}
}
}
OperationEnum枚举类中定义了一些操作
代码
using System;
using System.Collections.Generic;
using System.Text;
namespace Log
{
public enum OperationEnum
{
Select,
Insert,
Update,
Delete
}
}
接下来就是配置Spring的AOP了
代码
<?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="UserDao" type="Log.UserDao, Log" />
<!-- Advice-->
<object id="LogAdvice" type="Log.BeforeAdvice, Log" />
<object id="autoLogProxyCreator" type="Spring.Aop.Framework.AutoProxy.ObjectNameAutoProxyCreator, Spring.Aop">
<property name="ObjectNames">
<list>
<value>*Dao</value>
</list>
</property>
<property name="InterceptorNames">
<list>
<value>LogAdvice</value>
</list>
</property>
</object>
</objects>
构建测试页面：
代码
using System;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using Spring.Context;
using Spring.Context.Support;
using Log;
public partial class _Default : System.Web.UI.Page
{
private IApplicationContext _ctx;
private IUserDao _userDao;
protected void Page_Load(object sender, EventArgs e)
{
User u = new User();
u.UserName = "huihui";
u.Password = "HUIHUI";
Session["user"] = u;
userDao.DeleteUser(u);
userDao.GetUserByName(u.UserName, u.Password);
}
private IApplicationContext ctx
{
get
{
if (_ctx == null)
{
_ctx = ContextRegistry.GetContext();
}
return _ctx;
}
}
private IUserDao userDao
{
get
{
if (_userDao == null)
{
_userDao = ctx["UserDao"] as IUserDao;
}
return _userDao;
}
}
}
运行可以看到日志中已经记录如下内容：
2009-12-14 23:39:46,890 [4] INFO AppLog [(null)] - UserName:huihui ,OperationTime:2009-12-14 23:39:46,OperationType:Delete,OperatedTarget:Log.UserDao,Method:Void DeleteUser(Log.User),Argument:Log.User
2009-12-14 23:39:46,921 [4] INFO AppLog [(null)] - UserName:huihui ,OperationTime:2009-12-14 23:39:46,OperationType:Select,OperatedTarget:Log.UserDao,Method:System.Collections.Generic.IList`1[Log.User] GetUserByName(System.String, System.String),Argument:huihui|HUIHUI
日志输出格式可以根据项目需要自行调整，如果需要给管理员（针对用户）看日志，很明显上面的输出可能不太合适，这就需要对此进行一些调整。比如UserDao映射到“用户信息表”等等。
