As the official version of Protocol buffers 3 has not yet been released, the official website (https://developers.google.com/protocol-buffers/docs/downloads) is currently only available for download to the 2.6.1 version.
To download PB3, you need to download it in Https://github.com/google/protobuf release (https://github.com/google/protobuf/releases)
The latest version of the current here is edition 3.0.0-beta-2
Take my Mac For example, I downloaded: protoc-3.0.0-beta-2-osx-x86_64.zip
After this decompression, the contents are as follows:
The PROTOC here is our tool for compiling proto into the specified language code file.
If you want to compile this tool yourself, you can download https://github.com/google/protobuf this code, compile method reference: http://www.cnblogs.com/ghj1976/p/4564133.html
Compiling code for the proto file into the specified language