using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;

namespace TestDoc.Infrastructure.Ex
{
    // You may need to install the Microsoft.AspNetCore.Http.Abstractions package into your project
    public class ExceptionMiddleware
    {
        private readonly RequestDelegate _next;

        public ExceptionMiddleware(RequestDelegate next)
        {
            _next = next;
        }

        public async Task Invoke(HttpContext httpContext)
        {
            try
            {
                await _next(httpContext);
            }
            catch (Exception ex)
            {
                httpContext.Response.StatusCode = 200;
                httpContext.Response.ContentType = "application/json; charset=utf-8";
                await httpContext.Response.WriteAsync("Exception！！");
            }
        }
    }

    // Extension method used to add the middleware to the HTTP request pipeline.
    public static class ExceptionMiddlewareExtensions
    {
        public static IApplicationBuilder UseExceptionMiddleware(this IApplicationBuilder builder)
        {
            return builder.UseMiddleware<ExceptionMiddleware>();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using TestDoc.Infrastructure.Ex;
using TestDoc.MiddleWare;

namespace TestDoc
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddControllersWithViews();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Home/Error");
            }
            app.UseStaticFiles();

            app.UseRouting();

            app.UseAuthorization();
            ///异常捕获的实现
            app.UseExceptionMiddleware();
            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllerRoute(
                    name: "default",
                    pattern: "{controller=Home}/{action=Index}/{id?}");
            });
        }
    }
}