1.maven

<dependency>
  <groupId>com.google.protobuf</groupId>
  <artifactId>protobuf-java</artifactId>
  <version>3.3.0</version>
</dependency>

2.编辑person_entity.proto文件

syntax = "proto2";

option java_package = "com.boomsecret.protobuf.proto";
option java_outer_classname = "PersonEntity";

message person_entity {
    required int32 id = 1;  // ID
    required string name = 2;   // 姓名
    optional string email = 3;  // 邮箱
}

3.下载protoc.exe，并生成.java文件

https://github.com/google/protobuf/releases
protoc.exe --java_out=.\..\src\main\java .\proto\person_entity.proto

(com.boomsecret.protobuf.proto.PersonEntity.java)

4.小李子

public class ProtoBufDemo {
    public static void main(String[] args) {
        PersonEntity.person_entity.Builder builder = PersonEntity.person_entity.newBuilder();
        builder.setId(100);
        builder.setName("jack");
        builder.setEmail("jack@email.com");

        person_entity personEntity = builder.build();
        System.out.println(personEntity.toString());

        byte[] bytes = personEntity.toByteArray();
        for (byte index : bytes) {
            System.out.print(index);
        }
        System.out.println();

        try {
            person_entity parsePersonEntity = person_entity.parseFrom(bytes);
            System.out.println(parsePersonEntity);
        } catch (InvalidProtocolBufferException e) {
            e.printStackTrace();
        }
    }
}

5.总结

protobuf比xml和json效率高很多，具体可以去了解下，这里不做详细介绍。