C# web api 自定义 异常

一、自定义

using WebApi.Result;

namespace WebApi.Exceptions
{
    public class ApiException : Exception
    {
        public ResultCodeEnum ErrorCodeEnum { get; }

        public ApiException(ResultCodeEnum resultCodeEnum) : base((resultCodeEnum.Message))
        {
            ErrorCodeEnum = resultCodeEnum;
        }
    }
}

二、中间件

using System.Net;
using System.Text.Json;
using WebApi.Exceptions;
using WebApi.Result;

namespace WebApi.Middlewares
{
    public class GlobalExceptionMiddleware
    {
        private readonly RequestDelegate _next;
        private readonly ILogger<GlobalExceptionMiddleware> _logger;

        public GlobalExceptionMiddleware(RequestDelegate next, ILogger<GlobalExceptionMiddleware> logger)
        {
            _next = next;
            _logger = logger;
        }

        public async Task InvokeAsync(HttpContext context)
        {
            try
            {
                await _next(context);
            }
            catch (Exception ex)
            {
                await HandleExceptionAsync(context, ex);
            }
        }

        private async Task HandleExceptionAsync(HttpContext context, Exception exception)
        {
            context.Response.ContentType = "application/json";
            context.Response.StatusCode = (int)HttpStatusCode.OK; 

            ApiResult result;

            // 判断 自己的
            if (exception is ApiException apiEx)
            {
                
                result = ApiResult.Fail(apiEx.ErrorCodeEnum);
                _logger.LogWarning($"异常拦截：{apiEx.ErrorCodeEnum.Message}");
            }
            else
            {
                // 其它的
                result = ApiResult.Fail(ResultCodeEnum.ServiceError.Code, $"系统发生未知错误: {exception.Message}");
                _logger.LogError(exception, "系统崩溃拦截");
            }

            // json字符串
            var json = JsonSerializer.Serialize(result, new JsonSerializerOptions { PropertyNamingPolicy = JsonNamingPolicy.CamelCase });
            await context.Response.WriteAsync(json);
        }
    }
}

三、添配置(Program.cs)

var app = builder.Build();

#region 中间件
app.UseMiddleware<GlobalExceptionMiddleware>();
#endregion