1.Program.cs中的 UseUrls("http://localhost:8080") 导致运行后err-empty-response，需移除，原因尚不得知。
2.连接Sql Server
System.Data.SqlClient.SqlException (0x80131904): A connection was successfully established with the server, but then an error occurred during the pre-login handshake. (provider: TCP Provider, error: 35 - An internal exception was caught)
解决方法:修改Dockerfile
FROM mcr.microsoft.com/dotnet/core/aspnet:3.1-buster-slim AS base 改成:
FROM mcr.microsoft.com/dotnet/core/aspnet:3.1-bionic AS base