示例很简单，是简单的地址簿应用，可以从文件读写联系人信息。

定义地址簿信息addressbook.proto

syntax = "proto2";

package tutorial;

option java_package = "com.example.tutorial";
option java_outer_classname = "AddressBookProtos";

message Person {
  required string name = 1;
  required int32 id = 2;
  optional string email = 3;

  enum PhoneType {
    MOBILE = 0;
    HOME = 1;
    WORK = 2;
  }

  message PhoneNumber {
    required string number = 1;
    optional PhoneType type = 2 [default = HOME];
  }

  repeated PhoneNumber phones = 4;
}

message AddressBook {
  repeated Person people = 1;
}

编译Protocol Buffers

protoc -I=$SRC_DIR --java_out=$DST_DIR $SRC_DIR/addressbook.proto