qing2005原文地址 C#实现自动化Log日志
在开发项目的时候，我们不免要使用Log记录日志，使用最多的是Log4Net和EntLib Log，在需要记录日志的代码处加入log.Write(日志信息)，假设我需要跟踪业务方法，记录方法的传递参数，执行时间，返回数据等；或者我需要查 看方法的调用关系，希望进入方法的时候自动记录参数信息，出方法时记录结果和执行时间信息。这时就是一个典型的AOP运用，Java在AOP方面是很容易 实现的，因为java有类加载器。但是.Net在AOP方面就不怎么容易，严格意义上.Net没有真正的AOP。这话并不代表.Net不能实现AOP，比 如：PostSharp和Enterprise library就能实现。
先介绍一下PostSharp，我们知道.net代码将编译成MSIL（微软中间语言），然后CPU将MSIL的exe文件生成本地CPU的二进制文件格式，PostSharp就是在编译过程中加入IL代码，因而完成AOP功能。
缺点：编译器需要PostSharp组件，维护代码困难，因为IL代码不好识别；
优点：使用方便（PostSharp2是收费版，破解也比较方便，在此不介绍破解）
这里我重点介绍如何使用Enterprise Library实现自动化Log。
1.首先我们需要下载Enterprise Library，最新为5.0版本；
2.新建一个控制台项目，并添加以下程序集
Microsoft.Practices.EnterpriseLibrary.Common
Microsoft.Practices.EnterpriseLibrary.Logging
Microsoft.Practices.EnterpriseLibrary.PolicyInjection
Microsoft.Practices.ServiceLocation
Microsoft.Practices.Unity
Microsoft.Practices.Unity.Interception
3.添加AutoLogCallHandler类，实现ICallHandler接口
这个类是执行调用目标方法，在调用目标方法前获取方法的参数信息，并用EntLib Log记录日志；
方法结束后，再次记录日志，并统计执行时间和异常处理
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Practices.Unity.InterceptionExtension;
using Microsoft.Practices.EnterpriseLibrary.Logging;
using Microsoft.Practices.EnterpriseLibrary.Common.Configuration;
using System.Diagnostics;
using System.Reflection; namespace AutoLog {
public class AutoLogCallHandler:ICallHandler { private LogWriter logWriter = EnterpriseLibraryContainer.Current.GetInstance<LogWriter>(); public AutoLogCallHandler() { } public IMethodReturn Invoke(IMethodInvocation input, GetNextHandlerDelegate getNext) {
StringBuilder sb = null;
ParameterInfo pi = null; string methodName = input.MethodBase.Name;
logWriter.Write(string.Format("Enter method " + methodName)); if (input.Arguments != null && input.Arguments.Count > 0) {
sb = new StringBuilder();
for (int i = 0; i < input.Arguments.Count; i++) {
pi = input.Arguments.GetParameterInfo(i);
sb.Append(pi.Name).Append(" : ").Append(input.Arguments[i]).AppendLine();
}
logWriter.Write(sb.ToString());
} Stopwatch sw = new Stopwatch();
sw.Start(); IMethodReturn result = getNext()(input, getNext);
//如果发生异常则，result.Exception != null
if (result.Exception != null) {
logWriter.Write("Exception:" + result.Exception.Message);
//必须将异常处理掉，否则无法继续执行
result.Exception = null;
} sw.Stop();
logWriter.Write(string.Format("Exit method {0}, use {1}.",methodName, sw.Elapsed)); return result;
} public int Order { get; set; }
}
}
4.要自动化日志就需要创建一个标记属性，指定方法能自动进行日志
这里就创建AutoLogCallHandlerAttribute标记属性
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Practices.Unity.InterceptionExtension;
using Microsoft.Practices.EnterpriseLibrary.Logging;
using System.Diagnostics;
using Microsoft.Practices.EnterpriseLibrary.Common.Configuration; namespace AutoLog { public class AutoLogCallHandlerAttribute:HandlerAttribute { public override ICallHandler CreateHandler(Microsoft.Practices.Unity.IUnityContainer container) {
return new AutoLogCallHandler() { Order = this.Order };
}
}
}
5.创建实体类
注意：我在Work和ToString方法上方加上了AutoLogCallHandler属性，它是AutoLogCallHandlerAttribute的简写形式。用以指示这两个方法用AutoLogCallHandler的Invoke来处理。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Practices.Unity; namespace AutoLog { public class Employee : MarshalByRefObject
{ public Employee() {} public string Name { get; set; } [AutoLogCallHandler()]
public void Work() {
Console.WriteLine("Now is {0},{1} is working hard!",DateTime.Now.ToShortTimeString(),Name);
throw new Exception("Customer Exception");
} [AutoLogCallHandler()]
public override string ToString() {
return string.Format("I'm {0}.",Name);
}
}
}
6.测试代码
注意：必须使用PolicyInjection.Create<Employee>()来创建对象，不然无法实现。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Practices.EnterpriseLibrary.PolicyInjection;
using Microsoft.Practices.Unity;
using Microsoft.Practices.EnterpriseLibrary.Logging;
using Microsoft.Practices.EnterpriseLibrary.Common.Configuration; namespace AutoLog {
class Program { private static LogWriter logWriter = EnterpriseLibraryContainer.Current.GetInstance<LogWriter>(); static void Main(string[] args) { Employee emp = PolicyInjection.Create<Employee>(); emp.Name = "Lele"; emp.Work();
Console.WriteLine(emp);
}
}
}
7.还需要用EntLib的配置工具完成Log配置，将Log信息写入Trace.log文件中
<?xml version="1.0"?>
<configuration>
<configSections>
<section name="loggingConfiguration" type="Microsoft.Practices.EnterpriseLibrary.Logging.Configuration.LoggingSettings, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.505.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="true" />
</configSections>
<loggingConfiguration name="" tracingEnabled="true" defaultCategory="General">
<listeners>
<add name="Flat File Trace Listener" type="Microsoft.Practices.EnterpriseLibrary.Logging.TraceListeners.FlatFileTraceListener, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.505.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"
listenerDataType="Microsoft.Practices.EnterpriseLibrary.Logging.Configuration.FlatFileTraceListenerData, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.505.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"
fileName="trace.log" formatter="Text Formatter" />
</listeners>
<formatters>
<add type="Microsoft.Practices.EnterpriseLibrary.Logging.Formatters.TextFormatter, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.505.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"
template="Timestamp: {timestamp}{newline}
Message: {message}{newline}
Category: {category}{newline}
Priority: {priority}{newline}
EventId: {eventid}{newline}
Severity: {severity}{newline}
Title:{title}{newline}
Machine: {localMachine}{newline}
App Domain: {localAppDomain}{newline}
ProcessId: {localProcessId}{newline}
Process Name: {localProcessName}{newline}
Thread Name: {threadName}{newline}
Win32 ThreadId:{win32ThreadId}{newline}
Extended Properties: {dictionary({key} - {value}{newline})}"
name="Text Formatter" />
</formatters>
<categorySources>
<add switchValue="All" name="General">
<listeners>
<add name="Flat File Trace Listener" />
</listeners>
</add>
</categorySources>
<specialSources>
<allEvents switchValue="All" name="All Events" />
<notProcessed switchValue="All" name="Unprocessed Category" />
<errors switchValue="All" name="Logging Errors & Warnings">
<listeners>
<add name="Flat File Trace Listener" />
</listeners>
</errors>
</specialSources>
</loggingConfiguration>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>
</startup>
</configuration>
好了，测试一下，控制台输入：
Now is 14:03,Lele is working hard!
I'm Lele.
再看看Trace.log文件内容：
----------------------------------------
Timestamp: // :: Message: Enter method Work Category: General Priority: - EventId: Severity: Information Title: Machine: PC4 App Domain: AutoLog.exe ProcessId: Process Name: D:\Codes\Enterprise Library\Enterprise Library Demos\PIAB\Demo\AutoLog\bin\Debug\AutoLog.exe Thread Name: Win32 ThreadId: Extended Properties:
----------------------------------------
----------------------------------------
Timestamp: // :: Message: Exception:Customer Exception Category: General Priority: - EventId: Severity: Information Title: Machine: PC4 App Domain: AutoLog.exe ProcessId: Process Name: D:\Codes\Enterprise Library\Enterprise Library Demos\PIAB\Demo\AutoLog\bin\Debug\AutoLog.exe Thread Name: Win32 ThreadId: Extended Properties:
----------------------------------------
----------------------------------------
Timestamp: // :: Message: Exit method Work, use ::00.0024272. Category: General Priority: - EventId: Severity: Information Title: Machine: PC4 App Domain: AutoLog.exe ProcessId: Process Name: D:\Codes\Enterprise Library\Enterprise Library Demos\PIAB\Demo\AutoLog\bin\Debug\AutoLog.exe Thread Name: Win32 ThreadId: Extended Properties:
----------------------------------------
----------------------------------------
Timestamp: // :: Message: Enter method ToString Category: General Priority: - EventId: Severity: Information Title: Machine: PC4 App Domain: AutoLog.exe ProcessId: Process Name: D:\Codes\Enterprise Library\Enterprise Library Demos\PIAB\Demo\AutoLog\bin\Debug\AutoLog.exe Thread Name: Win32 ThreadId: Extended Properties:
----------------------------------------
----------------------------------------
Timestamp: // :: Message: Exit method ToString, use ::00.0001410. Category: General Priority: - EventId: Severity: Information Title: Machine: PC4 App Domain: AutoLog.exe ProcessId: Process Name: D:\Codes\Enterprise Library\Enterprise Library Demos\PIAB\Demo\AutoLog\bin\Debug\AutoLog.exe Thread Name: Win32 ThreadId: Extended Properties:
----------------------------------------
实现了自动化Log后，回过头来再看第5步，Employee继承了MarshalByRefObject，一般我们的业务类或数据访问类都有基类，那么我们就需要使用接口
这里我添加一个IEmployee接口，里面就Work方法（ToString是重写Object的）。
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Practices.Unity; namespace AutoLog { public interface IEmployee {
void Work();
} public class Employee : IEmployee
{ public Employee() {
//this.Name = "Lele";
} public string Name { get; set; } [AutoLogCallHandler()]
public void Work() {
Console.WriteLine("Now is {0},{1} is working hard!",DateTime.Now.ToShortTimeString(),Name);
throw new Exception("Customer Exception");
} [AutoLogCallHandler()]
public override string ToString() {
return string.Format("I'm {0}.",Name);
}
}
}
然后在测试类改动一下
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Practices.EnterpriseLibrary.PolicyInjection;
using Microsoft.Practices.Unity;
using Microsoft.Practices.EnterpriseLibrary.Logging;
using Microsoft.Practices.EnterpriseLibrary.Common.Configuration; namespace AutoLog {
class Program { private static LogWriter logWriter = EnterpriseLibraryContainer.Current.GetInstance<LogWriter>(); static void Main(string[] args) { IEmployee emp = PolicyInjection.Create<Employee, IEmployee>(); emp.Work();
Console.WriteLine(emp);
}
}
}