Swashbuckle.AspNetCore.SwaggerGen.SwaggerGeneratorException: Ambiguous HTTP method for action

访问swagger时报错，查看日志后如下：

2021-02-07 10:42:57.098 +08:00 [ERR] An unhandled exception has occurred while executing the request.
Swashbuckle.AspNetCore.SwaggerGen.SwaggerGeneratorException: Ambiguous HTTP method for action - xxx.Controllers.xxxAuthController.GetToken (xxx.HttpApi). Actions require an explicit HttpMethod binding for Swagger/OpenAPI 3.0
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GenerateOperations(IEnumerable`1 apiDescriptions, SchemaRepository schemaRepository)
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GeneratePaths(IEnumerable`1 apiDescriptions, SchemaRepository schemaRepository)
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GetSwagger(String documentName, String host, String basePath)
   at Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider)
   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
   at IdentityServer4.Hosting.IdentityServerMiddleware.Invoke(HttpContext context, IEndpointRouter router, IUserSession session, IEventService events, IBackChannelLogoutService backChannelLogoutService)
   at IdentityServer4.Hosting.MutualTlsEndpointMiddleware.Invoke(HttpContext context, IAuthenticationSchemeProvider schemes)
   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
   at IdentityServer4.Hosting.BaseUrlMiddleware.Invoke(HttpContext context)
   at Volo.Abp.AspNetCore.MultiTenancy.MultiTenancyMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
   at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.<>c__DisplayClass6_1.<<UseMiddlewareInterface>b__1>d.MoveNext()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Builder.ApplicationBuilderAbpJwtTokenMiddlewareExtension.<>c__DisplayClass0_0.<<UseJwtTokenMiddleware>b__0>d.MoveNext()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
   at Volo.Abp.AspNetCore.Tracing.AbpCorrelationIdMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
   at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.<>c__DisplayClass6_1.<<UseMiddlewareInterface>b__1>d.MoveNext()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Localization.RequestLocalizationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.RequestLocalization.AbpRequestLocalizationMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
   at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.<>c__DisplayClass6_1.<<UseMiddlewareInterface>b__1>d.MoveNext()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)
2021-02-07 10:42:57.128 +08:00 [INF] Request finished HTTP/2 GET https://localhost:44321/swagger/v1/swagger.json - - - 500 - text/plain 130.2839ms

解决方法：需要指定访问方式，controller中给方法添加属性 [HttpGet]或[HttpPost]。