syntax = "proto3"; // message 语法关键字 定义一个消息 message Person { string name = 1; int32 id = 2; string email = 3; enum PhoneType { MOBILE = 0; HOME = 1; WORK = 2; } // 嵌套一个 message message PhoneNumber { repeated string number = 1; PhoneType type = 2; } // 上面定义的消息要被使用 repeated PhoneNumber phones = 4; } message AddressBook { repeated Person people = 1; }