Dockerfile如下：

FROM mcr.microsoft.com/dotnet/core/aspnet:2.1-stretch-slim AS base

WORKDIR /app

EXPOSE 80

FROM mcr.microsoft.com/dotnet/core/sdk:2.1-stretch AS build

WORKDIR /src

//这一行copy是没有问题的，由于执行docker build的目录就是在项目根目录下

COPY ["Api.Admin.csproj", "Api.Admin/"]

//下面的4个类库项目，是api.admin项目依赖的项目(因为没有依赖nuget包，直接从本地项目引用)

COPY ["../lib-common/Api.Common/Api.Common.csproj", "../lib-common/Api.Common/"]

COPY ["../lib-common/Api.Common1/Api.Common1.csproj", "../lib-common/Api.Common1/"]

COPY ["../lib-common/Api.Common2/Api.Common2.csproj", "../lib-common/Api.Common2/"]

COPY ["../lib-common/Api.Common3/Api.Common3.csproj", "../lib-common3/Api.Common3/"]

RUN dotnet restore "Api.Admin/Api.Admin.csproj"

COPY . .

WORKDIR "/src/Api.Admin"

RUN dotnet build "Api.Admin.csproj" -c Release -o /app/build

FROM build AS publish

RUN dotnet publish "Api.Admin.csproj" -c Release -o /app/publish

FROM base AS final

WORKDIR /app

COPY --from=publish /app/publish .

ENTRYPOINT ["dotnet", "Api.Admin.dll"]

cmd定位到api.admin项目目录下，执行docker build 命令，会提示定位到

COPY ["../lib-common/Api.Common/Api.Common.csproj", "../lib-common/Api.Common/"]

这一行错误，COPY failed: Forbidden path outside the build context:

.netcoreDockerfile

问题补充：想到的其他办法有2个：

1、项目依赖改成nuget包方式引用

2、在Dockerfile中，去掉编译的命令，只保留考本和容器启动的命令，在本地发布好之后，再执行docker build.