1.https://github.com/protocolbuffers/protobuf/releases去这里下载。
2.然后:(在解压缩的目录下执行)
C:\Users\soda\Downloads\protobuf-all-3.20.0\protobuf-3.20.0>dart pub global activate protoc_plugin
3.你会看到:
Pub installs executables into C:\Users\soda\AppData\Local\Pub\Cache\bin, which is not on your path.