protobuf 学习总结

1 google protocol buffer

1.1  Definition

1.1.1  google开发的二进制的数据交换格式，独立于语言，独立于平台

1.1.2  提供了三种语言的实现，java、c++、Python

1.2  Function

1.2.1  用于分布式应用之间的数据通信或者异构环境下的数据交换

1.2.2 常用于网络传输、配置文件、数据存储等领域

1.3 Advantage

1.3.1 protobuf advantage

1.3.1.1 数据传输效率高

1.3.1.2 支持java、c++、Python，序列化和反序列化效率高

1.3.1.3 相比json、xml而言，节省消息空间

1.3.1.4 简单易用，可以按照一定语法定义消息格式，然后使用protoc命令行工具生成相应类

1.3.2 protobuf disadvantage

1.3.2.1 对象结构体有限制，只适用于内部系统

1.3.3 protobuf & thrift &json &xml &binary

1.3.3.1 thrift

1、2007年Facebook开发的跨语言的轻量级RPC消息和数据交换框架

2、能生成多种语言，C++, Java,Python, PHP, Ruby, Erlang, Perl, Haskell, C#, Cocoa, Smalltalk, OCaml

3、较protobuf而言，thrift功能丰富，支持语言多，资料少，学习成本高

2 Hello World之protobuf

2.1 reference

http://blog.youkuaiyun.com/luyee2010/article/details/8206090

2.2 project structure

2.3 编写.proto文件

msg.proto

option java_package = "com.protobuftest.protobuf"; option java_outer_classname = "PersonProbuf";   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 phone = 4;     message CountryInfo {           required string name = 1;           required string code = 2;           optional int32 number = 3;   } }   message AddressBook {   repeated Person person = 1; }

2.4 protoc工具生成java bean

在proto.exe目录下执行命令：protoc –java_out=./src ./proto/msg.proto

2.5 使用java bean

TestProtobuf.java

package com.protobuftest.protobuf;   import java.util.List;   import com.google.protobuf.InvalidProtocolBufferException; import com.protobuftest.protobuf.PersonProbuf; import com.protobuftest.protobuf.PersonProbuf.Person; import com.protobuftest.protobuf.PersonProbuf.Person.PhoneNumber;   public class TestProtobuf {          /**           * @param args           */          public static void main(String[] args) {                    // TODO Auto-generated method stub                    PersonProbuf.Person.Builder builder = PersonProbuf.Person.newBuilder();                    builder.setEmail("kkk@email.com");                    builder.setId(1);                    builder.setName("TestName");                   builder.addPhone(PersonProbuf.Person.PhoneNumber.newBuilder().setNumber("131111111")                                      .setType(PersonProbuf.Person.PhoneType.MOBILE));                   builder.addPhone(PersonProbuf.Person.PhoneNumber.newBuilder().setNumber("011111")                                      .setType(PersonProbuf.Person.PhoneType.HOME));                    Person person = builder.build();                    byte[] buf = person.toByteArray();                    try {                             Person person2 = PersonProbuf.Person.parseFrom(buf);                             System.out.println(person2.getName() + ", " + person2.getEmail());                             List<PhoneNumber> lstPhones = person2.getPhoneList();                             for (PhoneNumber phoneNumber : lstPhones) {                                      System.out.println(phoneNumber.getNumber());                             }                    } catch (InvalidProtocolBufferException e) {                             // TODO Auto-generated catch block                             e.printStackTrace();                    }                    System.out.println(buf);          } }

3 protobuf data type