Asp.net Core Filter过滤器异常处理

本文旨在：

1 继承ExceptionFilterAttribute，重写Override OnException(ExceptionContext context)处理异常

2 在.netCore中配置属性文件ExceptionFilterAttribute的构造方法注入

现在我们逐步实现以上两个功能：

1 继承ExceptionFilterAttribute，重写Override OnException(ExceptionContext context)处理异常

新建class文件，命名ExceptionHandler,继承特性ExceptionFilterAttribute，重写 OnException,处理异常，这里我封装了ReturnResult方法处理ActionResult

public class ExceptionHandle : ExceptionFilterAttribute
{
 	public override void OnException(ExceptionContext context)
    {
        var ex = context.Exception;
        var controllername = context.RouteData.Values["controller"].ToString();
        var actionname = context.RouteData.Values["action"].ToString();

        if (context.ExceptionHandled == false)
        {
        context.Result= ReturnResult(resultType.ContentResult,ex);
        }
        context.ExceptionHandled = true; //异常已处理了
    }
}

　　

ReturnResult方法代码：这里总结了三种形式的输出1 ContentResult重写请求页面内容输出异常,2 JsonResult Json格式返回异常,3 Redirect页面跳转

        private IActionResult ReturnResult(resultType rtype, Exception ex)
        {
            IActionResult result;
            switch (rtype)
            {
                case resultType.ContentResult:
                    result = new ContentResult
                    {
                        Content = ex.Message,
                        StatusCode = StatusCodes.Status500InternalServerError,
                        ContentType = "text/html;charset=utf-8"
                    };
                    break;
                case resultType.JsonResult:
                    result = new JsonResult(new { msg = ex.Message });
                    break;
                case resultType.Redirect:
                    result = new RedirectToRouteResult(
                        new RouteValueDictionary{
                            { "controller","Home"},
                            {"action","Error" },
                            {"msg",ex.Message }
                        }
                    );
                    break;
                default:
                    result = new RedirectResult("../home/error");
                    break;
            }
            return result;
        }
        enum resultType
        {
            ContentResult = 1,
            JsonResult = 2,
            Redirect = 3
        }

　　

2 使用.netCore做依赖注入，这里我们为ExceptionHandle属性文件做注入配置

startup.cs 配置服务：

    public void ConfigureServices(IServiceCollection services)
    {
    ...
    services.AddScoped<ExceptionHandle>();
    }

　使用：构造方法根据需要补充参数，.netcore会自动为该传参做注入

public class ExceptionHandle : ExceptionFilterAttribute
    {
        private readonly ILogger<ExceptionHandle> _logger;
        public ExceptionHandle(ILogger<ExceptionHandle> logger)
        {
            _logger = logger;
        }
        public override void OnException(ExceptionContext context)
    	{
         _logger.LogError(ex.Message, context.Exception);//调用
         }
    }

　　Action调用：ServiceFilter

[ServiceFilter(typeof(ExceptionHandle))]
public IActionResult Index(DateTime dt, long sjc)
{
    var chushu = 0;
    var i = 1 / chushu;
    return View()
}

　　

总结：定义继承自ExceptionFilterAttribute属性类的Filter文件类，重写OnException方法，如果不需要在属性类中使用其他服务当日也无需做注入，调用在Action上一行写上[AttributeName]即可

//[ServiceFilter(typeof(ExceptionHandle))] 

[ExceptionHandle]

public IActionResult Index(DateTime dt, long sjc)
{
    var chushu = 0;
    var i = 1 / chushu;
    return View()
}