[转] C#实现自动化Log日志

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);
            }
        }
    }