MVC学习系列——Filter扩展

     在MVC中，Filter也是可以扩展的。在此，本人对Filter的理解就是AOP，不知道各位大侠，有什么高的见解，呵呵。。。

首先MVC四大过滤神器IAuthorizationFilter，IActionFilter，IResultFilter，IExceptionFilter。

在此之前，我们先安装Log4net日志神器：

看下项目的引用

配置文件

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <configSections>
    <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/>
  </configSections>
  <log4net>
    <appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
      <!--日志路径-->
      <param name= "File" value= "D:\App_Log\"/>
      <!--是否是向文件中追加日志-->
      <param name= "AppendToFile" value= "true"/>
      <!--log保留天数-->
      <param name= "MaxSizeRollBackups" value= "10"/>
      <!--日志文件名是否是固定不变的-->
      <param name= "StaticLogFileName" value= "false"/>
      <!--日志文件名格式为:2008-08-31.log-->
      <param name= "DatePattern" value= "yyyy-MM-dd&quot;.log&quot;"/>
      <!--日志根据日期滚动-->
      <param name= "RollingStyle" value= "Date"/>
      <layout type="log4net.Layout.PatternLayout">
        <param name="ConversionPattern" value="%d [%t] %-5p %c - %m%n %loggername" />
      </layout>
    </appender>
    <!-- 控制台前台显示日志 -->
    <appender name="ColoredConsoleAppender" type="log4net.Appender.ColoredConsoleAppender">
      <mapping>
        <level value="ERROR" />
        <foreColor value="Red, HighIntensity" />
      </mapping>
      <mapping>
        <level value="Info" />
        <foreColor value="Green" />
      </mapping>
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%n%date{HH:mm:ss,fff} [%-5level] %m" />
      </layout>

      <filter type="log4net.Filter.LevelRangeFilter">
        <param name="LevelMin" value="Info" />
        <param name="LevelMax" value="Fatal" />
      </filter>
    </appender>
    <root>
      <!--(高) OFF > FATAL > ERROR > WARN > INFO > DEBUG > ALL (低) -->
      <level value="all" />
      <appender-ref ref="ColoredConsoleAppender"/>
      <appender-ref ref="RollingLogFileAppender"/>
    </root>
  </log4net>
  <system.web>
    <compilation debug="true" targetFramework="4.5.2" />
    <httpRuntime targetFramework="4.5.2" />
  </system.web>
</configuration>

增加LogHelper帮助类

 public class LogHelper
    {
        public static void WriteLog_Error(Type t, Exception ex)
        {
            log4net.ILog log = log4net.LogManager.GetLogger(t);
            log.Error("Unhandled exception", ex);
        }

        public static void WriteLog_Error(Type t, string msg)
        {
            log4net.ILog log = log4net.LogManager.GetLogger(t);
            log.Error(msg);
        }

        public static void WriteLog_Info(Type t, string msg)
        {
            log4net.ILog log = log4net.LogManager.GetLogger(t);
            log.Info(msg);
        }
    }

还有一个重要的一步，在Gobal类中，要申明：

//加载配置文件
            var logCfg = new FileInfo(AppDomain.CurrentDomain.BaseDirectory + "Log4Net.config");
            XmlConfigurator.ConfigureAndWatch(logCfg);

ok，到这里log4net，配置完成。

 

现在，我来扩展IExceptionFilter这个过滤器。

新建Log4NetExceptionFilter类，继承接口IExceptionFilter

public class Log4NetExceptionFilter : IExceptionFilter
    {
        public void OnException(ExceptionContext filterContext)
        {
            LogHelper.WriteLog_Error(GetType(), filterContext.Exception);
        }
    }

在FilterConfig中申明自己的异常处理：

 public class FilterConfig
    {
        public static void RegisterGlobalFilters(GlobalFilterCollection filters)
        {
            //filters.Add(new HandleErrorAttribute());
            //加上自己的异常
            filters.Add(new Log4NetExceptionFilter());
        }
    }

测试：在HomeController的GetXmlResult，手工增加异常：

 public XmlResult GetXmlResult()
        {
            int a = 1;
            int b = 0;
            int c = a / b;

            StudentViewModel viewModel = new StudentViewModel();
            viewModel.ID = "1";
            viewModel.Name ="Zhangsan";
            viewModel.Gender = "Man";

            return new XmlResult(viewModel);
        }

结果：

 

在介绍一下ActionFilterAttribute，这个特性有两个接口IActionFilter, IResultFilter。

因此，新建MyActionFilterAttribute，继承于ActionFilterAttribute

public class MyActionFilterAttribute: ActionFilterAttribute
    {
        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            LogHelper.WriteLog_Info(GetType(), "OnActionExecuting");
            base.OnActionExecuting(filterContext);
        }
        public override void OnActionExecuted(ActionExecutedContext filterContext)
        {
            LogHelper.WriteLog_Info(GetType(), "OnActionExecuted");
            base.OnActionExecuted(filterContext);
        }

        public override void OnResultExecuting(ResultExecutingContext filterContext)
        {
            LogHelper.WriteLog_Info(GetType(), "OnResultExecuting");
            base.OnResultExecuting(filterContext);
        }

        public override void OnResultExecuted(ResultExecutedContext filterContext)
        {
            LogHelper.WriteLog_Info(GetType(), "OnResultExecuted");
            base.OnResultExecuted(filterContext);
        }
    }

测试：在HomeController的GetXmlResult的方法上，增加MyActionFilterAttribute特性。ps:这里已经去掉刚刚手工增加的异常。

  [MyActionFilterAttribute]
        public XmlResult GetXmlResult()
        {
            StudentViewModel viewModel = new StudentViewModel();
            viewModel.ID = "1";
            viewModel.Name ="Zhangsan";
            viewModel.Gender = "Man";
            return new XmlResult(viewModel);
        }

结果：