google protobuf使用

google protobuf使用

下载的是github上的：https://github.com/google/protobuf

 

If you get the source from github, you need to generate the configure script first:

$ ./autogen.sh

This will download gtest source (which is used for C++ Protocol Buffer unit-tests) to the current directory and run automake, autoconf, etc. to generate the configure script and various template makefiles.

运行这个会下载gtest(google单元测试框架）。由于google访问不了，这个这个没有成功。

 

直接在csdnhttp://download.youkuaiyun.com/download/canlets/6878023 下载的protobuf2.5.0.

tar zxvf protobuf-2.4.1.tar.gz
cd protobuf-2.4.1
./configure
make
make check
make install
安装结束。
验证：
查看是否安装成功：protoc --version
如果出现：libprotoc 2.4.1 则说明安装成功！
如果出现错误：

 

tar zxvf protobuf-2.5.0.tar.gz
 
./configure
make
make check
make install
安装结束。
验证：
查看是否安装成功：protoc --version
如果出现：libprotoc 2.5.0 则说明安装成功！
如果出现错误：
protoc: error while loading shared libraries: libprotobuf.so.0: cannot open
shared object file: No such file or directory
The issue is that Ubuntu 8.04 doesn't include /usr/local/lib in
library paths.
To fix it for your current terminal session, just type in
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib

 

　安装完成后在终端下执行

　　vim ~/.profile (我加在了/etc/profile里)

　　打开配置文件，在该文件中添加

　　export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib

　　然后保存退出，接下来执行

　　source ~/.profile

　　是配置文件修改生效，最后执行

　　protoc --version

　　查看protobuf版本以测试是否安装成功

 

 

root@iZ23onhpqvwZ:~/ms/protobuf/protobuf-2.5.0# protoc --version
libprotoc 2.5.0

转：protobuf c++入门

1、在.proto文件中定义消息格式

2、使用protobuf编译器

3、使用c++ api来读写消息

 

windows  protobuf编译

我下载的是2.6.1的版本

打开vsprojects目录,里面有一个.sln文件，打开

vsprojects里面有一个readme.txt，告诉了如何安装：

This directory contains project files for compiling Protocol Buffers using
MSVC.  This is not the recommended way to do Protocol Buffer development --
we prefer to develop under a Unix-like environment -- but it may be more
accessible to those who primarily work with MSVC.

Compiling and Installing
========================

1) Open protobuf.sln in Microsoft Visual Studio.
2) Choose "Debug" or "Release" configuration as desired.*
3) From the Build menu, choose "Build Solution".  Wait for compiling to finish.
4) From a command shell, run tests.exe and lite-test.exe and check that all
   tests pass.
5) Run extract_includes.bat to copy all the public headers into a separate
   "include" directory (under the top-level package directory).
6) Copy the contents of the include directory to wherever you want to put
   headers.
7) Copy protoc.exe wherever you put build tools (probably somewhere in your
   PATH).
8) Copy libprotobuf.lib, libprotobuf-lite.lib, and libprotoc.lib wherever you
   put libraries.

* To avoid conflicts between the MSVC debug and release runtime libraries, when
  compiling a debug build of your application, you may need to link against a
  debug build of libprotobuf.lib.  Similarly, release builds should link against
  release libs.

DLLs vs. static linking
=======================

Static linking is now the default for the Protocol Buffer libraries.  Due to
issues with Win32's use of a separate heap for each DLL, as well as binary
compatibility issues between different versions of MSVC's STL library, it is
recommended that you use static linkage only.  However, it is possible to
build libprotobuf and libprotoc as DLLs if you really want.  To do this,
do the following:

  1) Open protobuf.sln in MSVC.
  2) For each of the projects libprotobuf, libprotobuf-lite, and libprotoc, do
     the following:
    2a) Right-click the project and choose "properties".
    2b) From the side bar, choose "General", under "Configuration Properties".
    2c) Change the "Configuration Type" to "Dynamic Library (.dll)".
    2d) From the side bar, choose "Preprocessor", under "C/C++".
    2e) Add PROTOBUF_USE_DLLS to the list of preprocessor defines.
  3) When compiling your project, make sure to #define PROTOBUF_USE_DLLS.

When distributing your software to end users, we strongly recommend that you
do NOT install libprotobuf.dll or libprotoc.dll to any shared location.
Instead, keep these libraries next to your binaries, in your application's
own install directory.  C++ makes it very difficult to maintain binary
compatibility between releases, so it is likely that future versions of these
libraries will *not* be usable as drop-in replacements.

If your project is itself a DLL intended for use by third-party software, we
recommend that you do NOT expose protocol buffer objects in your library's
public interface, and that you statically link protocol buffers into your
library.

ZLib support
============

If you want to include GzipInputStream and GzipOutputStream
(google/protobuf/io/gzip_stream.h) in libprotoc, you will need to do a few
additional steps:

1) Obtain a copy of the zlib library.  The pre-compiled DLL at zlib.net works.
2) Make sure zlib's two headers are in your include path and that the .lib file
   is in your library path.  You could place all three files directly into the
   vsproject directory to compile libprotobuf, but they need to be visible to
   your own project as well, so you should probably just put them into the
   VC shared icnlude and library directories.
3) Right-click on the "tests" project and choose "properties".  Navigate the
   sidebar to "Configuration Properties" -> "Linker" -> "Input".
4) Under "Additional Dependencies", add the name of the zlib .lib file (e.g.
   zdll.lib).  Make sure to update both the Debug and Release configurations.
5) If you are compiling libprotobuf and libprotoc as DLLs (see previous
   section), repeat steps 2 and 3 for the libprotobuf and libprotoc projects.
   If you are compiling them as static libraries, then you will need to link
   against the zlib library directly from your own app.
6) Edit config.h (in the vsprojects directory) and un-comment the line that
   #defines HAVE_ZLIB.  (Or, alternatively, define this macro via the project
   settings.)

Notes on Compiler Warnings
==========================

The following warnings have been disabled while building the protobuf libraries
and compiler.  You may have to disable some of them in your own project as
well, or live with them.

C4018 - 'expression' : signed/unsigned mismatch
C4146 - unary minus operator applied to unsigned type, result still unsigned
C4244 - Conversion from 'type1' to 'type2', possible loss of data.
C4251 - 'identifier' : class 'type' needs to have dll-interface to be used by
        clients of class 'type2'
C4267 - Conversion from 'size_t' to 'type', possible loss of data.
C4305 - 'identifier' : truncation from 'type1' to 'type2'
C4355 - 'this' : used in base member initializer list
C4800 - 'type' : forcing value to bool 'true' or 'false' (performance warning)
C4996 - 'function': was declared deprecated

C4251 is of particular note, if you are compiling the Protocol Buffer library
as a DLL (see previous section).  The protocol buffer library uses templates in
its public interfaces.  MSVC does not provide any reasonable way to export
template classes from a DLL.  However, in practice, it appears that exporting
templates is not necessary anyway.  Since the complete definition of any
template is available in the header files, anyone importing the DLL will just
end up compiling instances of the templates into their own binary.  The
Protocol Buffer implementation does not rely on static template members being
unique, so there should be no problem with this, but MSVC prints warning
nevertheless.  So, we disable it.  Unfortunately, this warning will also be
produced when compiling code which merely uses protocol buffers, meaning you
may have to disable it in your code too.

按照上面的很难成功，搞了n次，终与生成了，参考下面的。

http://blog.youkuaiyun.com/kandyer/article/details/10042715

0、为何使用protobuf?

 

1、原始内存数据结构，可以以二进制方式sent/saved.这种方式需要相同的内存布局和字节序。

2、以ad-hoc方式将数据项编码成一个简单字符串----比如，将4个int类型编码成"12:3:-23:67"。这种方式简灵活。适用于简单数据。

3、将数据序列化为XML。这种方式很流行，因为xml可读性好，编码解码方便，性能也好。仅仅XML dom树比较复杂。

 

protobuf可以很好的解决上述问题。你编写一个.proto文件来描述数据结构。protobuf编译器使用它创建一个类，使用二进制方式自动编码/解码该数据结构。生成的类提供getter/setter方法。

 

最重要的是，protobuf支持在此基础上进行格式扩展。

关于数据类型：

要通信，必须有协议，否则双方无法理解对方的码流。在protobuf中，协议是由一系列的消息组成的。因此最重要的就是定义通信时使用到的消息格式。

 

Protobuf消息定义

消息由至少一个字段组合而成，类似于C语言中的结构。每个字段都有一定的格式。

字段格式：限定修饰符① | 数据类型② | 字段名称③ | = | 字段编码值④ | [字段默认值⑤]

①．限定修饰符包含 required\optional\repeated

 

Required: 表示是一个必须字段，必须相对于发送方，在发送消息之前必须设置该字段的值，对于接收方，必须能够识别该字段的意思。发送之前没有设置required字段或者无法识别required字段都会引发编解码异常，导致消息被丢弃。

Optional：表示是一个可选字段，可选对于发送方，在发送消息时，可以有选择性的设置或者不设置该字段的值。对于接收方，如果能够识别可选字段就进行相应的处理，如果无法识别，则忽略该字段，消息中的其它字段正常处理。---因为optional字段的特性，很多接口在升级版本中都把后来添加的字段都统一的设置为optional字段，这样老的版本无需升级程序也可以正常的与新的软件进行通信，只不过新的字段无法识别而已，因为并不是每个节点都需要新的功能，因此可以做到按需升级和平滑过渡。

Repeated：表示该字段可以包含0~N个元素。其特性和optional一样，但是每一次可以包含多个值。可以看作是在传递一个数组的值。

 

②．数据类型

 

Protobuf定义了一套基本数据类型。几乎都可以映射到C++\Java等语言的基础数据类型.

      

protobuf 数据类型	描述	打包	C++语言映射
bool	布尔类型	1字节	bool
double	64位浮点数	N	double
float	32为浮点数	N	float
int32	32位整数、	N	int
uin32	无符号32位整数	N	unsigned int
int64	64位整数	N	__int64
uint64	64为无符号整	N	unsigned __int64
sint32	32位整数，处理负数效率更高	N	int32
sing64	64位整数 处理负数效率更高	N	__int64
fixed32	32位无符号整数	4	unsigned int32
fixed64	64位无符号整数	8	unsigned __int64
sfixed32	32位整数、能以更高的效率处理负数	4	unsigned int32
sfixed64	64为整数	8	unsigned __int64
string	只能处理 ASCII字符	N	std::string
bytes	用于处理多字节的语言字符、如中文	N	std::string
enum	可以包含一个用户自定义的枚举类型uint32	N(uint32)	enum
message	可以包含一个用户自定义的消息类型	N	object of class

N 表示打包的字节并不是固定。而是根据数据的大小或者长度。

例如int32，如果数值比较小，在0~127时，使用一个字节打包。

关于枚举的打包方式和uint32相同。

关于message，类似于C语言中的结构包含另外一个结构作为数据成员一样。

关于 fixed32 和int32的区别。fixed32的打包效率比int32的效率高，但是使用的空间一般比int32多。因此一个属于时间效率高，一个属于空间效率高。根据项目的实际情况，一般选择fixed32，如果遇到对传输数据量要求比较苛刻的环境，可以选择int32.

③．字段名称

 

字段名称的命名与C、C++、Java等语言的变量命名方式几乎是相同的。

protobuf建议字段的命名采用以下划线分割的驼峰式。例如 first_name 而不是firstName.

④．字段编码值

有了该值，通信双方才能互相识别对方的字段。当然相同的编码值，其限定修饰符和数据类型必须相同。

编码值的取值范围为 1~2^32（4294967296）。

其中 1~15的编码时间和空间效率都是最高的，编码值越大，其编码的时间和空间效率就越低（相对于1-15），当然一般情况下相邻的2个值编码效率的是相同的，除非2个值恰好实在4字节，12字节，20字节等的临界区。比如15和16.

1900~2000编码值为Google protobuf 系统内部保留值，建议不要在自己的项目中使用。

protobuf 还建议把经常要传递的值把其字段编码设置为1-15之间的值。

消息中的字段的编码值无需连续，只要是合法的，并且不能在同一个消息中有字段包含相同的编码值。

建议：项目投入运营以后涉及到版本升级时的新增消息字段全部使用optional或者repeated，尽量不实用required。如果使用了required，需要全网统一升级，如果使用optional或者repeated可以平滑升级。

 

⑤．默认值。当在传递数据时，对于required数据类型，如果用户没有设置值，则使用默认值传递到对端。当接受数据是，对于optional字段，如果没有接收到optional字段，则设置为默认值。

 

关于import

protobuf 接口文件可以像C语言的h文件一个，分离为多个，在需要的时候通过 import导入需要对文件。其行为和C语言的#include或者java的import的行为大致相同。

关于package

避免名称冲突，可以给每个文件指定一个package名称，对于java解析为java中的包。对于C++则解析为名称空间。

 

关于message

支持嵌套消息，消息可以包含另一个消息作为其字段。也可以在消息内定义一个新的消息。

关于enum

枚举的定义和C++相同，但是有一些限制。

枚举值必须大于等于0的整数。

使用分号(;)分隔枚举变量而不是C++语言中的逗号(,)

eg.

enum VoipProtocol 

{

    H323 = 1;

    SIP  = 2;

    MGCP = 3;

    H248 = 4;

}

 

 

 

示例

 

1、定义协议格式

package tutorial;  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 AddressBook {
   repeated Person person = 1; 
}

该结构与c++或java很像.

 

.proto文件以包声明开始，防止名字冲突。

简单类型：bool, int32, float, double, string.

其它类型：如上述的Person, PhoneNumber

 

类型可以嵌套。

“=1”， “=2”标识唯一“tag”.tag数1-15需要至少一个字节。

 

required: 必须设置它的值

optional: 可以设置，也可以不设置它的值

repeated: 可以认为是动态分配的数组

google工程师认为使用required威害更大， 他们更喜欢使用optional, repeated.

  

其中字段标签标示了字段在二进制流中存放的位置，这个是必须的，而且序列化与反序列化的时候相同的字段的Tag值必须对应，否则反序列化会出现意想不到的问题。

 

2、编译你的协议

 

运行protoc 来生成c++文件：

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

1. protoc proto文件路径 --cpp_out=C++代码文件导出目录  在使用中我发现有一点需要注意，就是--cpp_out的目录是根据proto文件的路径为基础的，也就是说：假设proto文件位于src目录下，希望将C++代码也导出到src目录下，那么--cpp_out直接=.就可以了。不需要再写一遍src/，如果写了src/，那么代码导出的目录将是src/src/（即使src/src不存在，也会被创建）

生成的文件为：

protoc --cpp_out=.    ./addressbook.proto 

 

addressbook.pb.h, 

addressbook.pb.cc

 

3、protobuf API

 整个头文件：

// Generated by the protocol buffer compiler.  DO NOT EDIT!
// source: addressbook.proto

#ifndef PROTOBUF_addressbook_2eproto__INCLUDED
#define PROTOBUF_addressbook_2eproto__INCLUDED

#include <string>

#include <google/protobuf/stubs/common.h>

#if GOOGLE_PROTOBUF_VERSION < 2006000
#error This file was generated by a newer version of protoc which is
#error incompatible with your Protocol Buffer headers.  Please update
#error your headers.
#endif
#if 2006001 < GOOGLE_PROTOBUF_MIN_PROTOC_VERSION
#error This file was generated by an older version of protoc which is
#error incompatible with your Protocol Buffer headers.  Please
#error regenerate this file with a newer version of protoc.
#endif

#include <google/protobuf/generated_message_util.h>
#include <google/protobuf/message.h>
#include <google/protobuf/repeated_field.h>
#include <google/protobuf/extension_set.h>
#include <google/protobuf/generated_enum_reflection.h>
#include <google/protobuf/unknown_field_set.h>
// @@protoc_insertion_point(includes)

namespace tutorial {

// Internal implementation detail -- do not call these.
void  protobuf_AddDesc_addressbook_2eproto();
void protobuf_AssignDesc_addressbook_2eproto();
void protobuf_ShutdownFile_addressbook_2eproto();

class Person;
class Person_PhoneNumber;
class AddressBook;

enum Person_PhoneType {
  Person_PhoneType_MOBILE = 0,
  Person_PhoneType_HOME = 1,
  Person_PhoneType_WORK = 2
};
bool Person_PhoneType_IsValid(int value);
const Person_PhoneType Person_PhoneType_PhoneType_MIN = Person_PhoneType_MOBILE;
const Person_PhoneType Person_PhoneType_PhoneType_MAX = Person_PhoneType_WORK;
const int Person_PhoneType_PhoneType_ARRAYSIZE = Person_PhoneType_PhoneType_MAX + 1;

const ::google::protobuf::EnumDescriptor* Person_PhoneType_descriptor();
inline const ::std::string& Person_PhoneType_Name(Person_PhoneType value) {
  return ::google::protobuf::internal::NameOfEnum(
    Person_PhoneType_descriptor(), value);
}
inline bool Person_PhoneType_Parse(
    const ::std::string& name, Person_PhoneType* value) {
  return ::google::protobuf::internal::ParseNamedEnum<Person_PhoneType>(
    Person_PhoneType_descriptor(), name, value);
}
// ===================================================================

class Person_PhoneNumber : public ::google::protobuf::Message {
 public:
  Person_PhoneNumber();
  virtual ~Person_PhoneNumber();

  Person_PhoneNumber(const Person_PhoneNumber& from);

  inline Person_PhoneNumber& operator=(const Person_PhoneNumber& from) {
    CopyFrom(from);
    return *this;
  }

  inline const ::google::protobuf::UnknownFieldSet& unknown_fields() const {
    return _unknown_fields_;
  }

  inline ::google::protobuf::UnknownFieldSet* mutable_unknown_fields() {
    return &_unknown_fields_;
  }

  static const ::google::protobuf::Descriptor* descriptor();
  static const Person_PhoneNumber& default_instance();

  void Swap(Person_PhoneNumber* other);

  // implements Message ----------------------------------------------

  Person_PhoneNumber* New() const;
  void CopyFrom(const ::google::protobuf::Message& from);
  void MergeFrom(const ::google::protobuf::Message& from);
  void CopyFrom(const Person_PhoneNumber& from);
  void MergeFrom(const Person_PhoneNumber& from);
  void Clear();
  bool IsInitialized() const;

  int ByteSize() const;
  bool MergePartialFromCodedStream(
      ::google::protobuf::io::CodedInputStream* input);
  void SerializeWithCachedSizes(
      ::google::protobuf::io::CodedOutputStream* output) const;
  ::google::protobuf::uint8* SerializeWithCachedSizesToArray(::google::protobuf::uint8* output) const;
  int GetCachedSize() const { return _cached_size_; }
  private:
  void SharedCtor();
  void SharedDtor();
  void SetCachedSize(int size) const;
  public:
  ::google::protobuf::Metadata GetMetadata() const;

  // nested types ----------------------------------------------------

  // accessors -------------------------------------------------------

  // required string number = 1;
  inline bool has_number() const;
  inline void clear_number();
  static const int kNumberFieldNumber = 1;
  inline const ::std::string& number() const;
  inline void set_number(const ::std::string& value);
  inline void set_number(const char* value);
  inline void set_number(const char* value, size_t size);
  inline ::std::string* mutable_number();
  inline ::std::string* release_number();
  inline void set_allocated_number(::std::string* number);

  // optional .tutorial.Person.PhoneType type = 2 [default = HOME];
  inline bool has_type() const;
  inline void clear_type();
  static const int kTypeFieldNumber = 2;
  inline ::tutorial::Person_PhoneType type() const;
  inline void set_type(::tutorial::Person_PhoneType value);

  // @@protoc_insertion_point(class_scope:tutorial.Person.PhoneNumber)
 private:
  inline void set_has_number();
  inline void clear_has_number();
  inline void set_has_type();
  inline void clear_has_type();

  ::google::protobuf::UnknownFieldSet _unknown_fields_;

  ::google::protobuf::uint32 _has_bits_[1];
  mutable int _cached_size_;
  ::std::string* number_;
  int type_;
  friend void  protobuf_AddDesc_addressbook_2eproto();
  friend void protobuf_AssignDesc_addressbook_2eproto();
  friend void protobuf_ShutdownFile_addressbook_2eproto();

  void InitAsDefaultInstance();
  static Person_PhoneNumber* default_instance_;
};
// -------------------------------------------------------------------

class Person : public ::google::protobuf::Message {
 public:
  Person();
  virtual ~Person();

  Person(const Person& from);

  inline Person& operator=(const Person& from) {
    CopyFrom(from);
    return *this;
  }

  inline const ::google::protobuf::UnknownFieldSet& unknown_fields() const {
    return _unknown_fields_;
  }

  inline ::google::protobuf::UnknownFieldSet* mutable_unknown_fields() {
    return &_unknown_fields_;
  }

  static const ::google::protobuf::Descriptor* descriptor();
  static const Person& default_instance();

  void Swap(Person* other);

  // implements Message ----------------------------------------------

  Person* New() const;
  void CopyFrom(const ::google::protobuf::Message& from);
  void MergeFrom(const ::google::protobuf::Message& from);
  void CopyFrom(const Person& from);
  void MergeFrom(const Person& from);
  void Clear();
  bool IsInitialized() const;

  int ByteSize() const;
  bool MergePartialFromCodedStream(
      ::google::protobuf::io::CodedInputStream* input);
  void SerializeWithCachedSizes(
      ::google::protobuf::io::CodedOutputStream* output) const;
  ::google::protobuf::uint8* SerializeWithCachedSizesToArray(::google::protobuf::uint8* output) const;
  int GetCachedSize() const { return _cached_size_; }
  private:
  void SharedCtor();
  void SharedDtor();
  void SetCachedSize(int size) const;
  public:
  ::google::protobuf::Metadata GetMetadata() const;

  // nested types ----------------------------------------------------

  typedef Person_PhoneNumber PhoneNumber;

  typedef Person_PhoneType PhoneType;
  static const PhoneType MOBILE = Person_PhoneType_MOBILE;
  static const PhoneType HOME = Person_PhoneType_HOME;
  static const PhoneType WORK = Person_PhoneType_WORK;
  static inline bool PhoneType_IsValid(int value) {
    return Person_PhoneType_IsValid(value);
  }
  static const PhoneType PhoneType_MIN =
    Person_PhoneType_PhoneType_MIN;
  static const PhoneType PhoneType_MAX =
    Person_PhoneType_PhoneType_MAX;
  static const int PhoneType_ARRAYSIZE =
    Person_PhoneType_PhoneType_ARRAYSIZE;
  static inline const ::google::protobuf::EnumDescriptor*
  PhoneType_descriptor() {
    return Person_PhoneType_descriptor();
  }
  static inline const ::std::string& PhoneType_Name(PhoneType value) {
    return Person_PhoneType_Name(value);
  }
  static inline bool PhoneType_Parse(const ::std::string& name,
      PhoneType* value) {
    return Person_PhoneType_Parse(name, value);
  }

  // accessors -------------------------------------------------------

  // required string name = 1;
  inline bool has_name() const;
  inline void clear_name();
  static const int kNameFieldNumber = 1;
  inline const ::std::string& name() const;
  inline void set_name(const ::std::string& value);
  inline void set_name(const char* value);
  inline void set_name(const char* value, size_t size);
  inline ::std::string* mutable_name();
  inline ::std::string* release_name();
  inline void set_allocated_name(::std::string* name);

  // required int32 id = 2;
  inline bool has_id() const;
  inline void clear_id();
  static const int kIdFieldNumber = 2;
  inline ::google::protobuf::int32 id() const;
  inline void set_id(::google::protobuf::int32 value);

  // optional string email = 3;
  inline bool has_email() const;
  inline void clear_email();
  static const int kEmailFieldNumber = 3;
  inline const ::std::string& email() const;
  inline void set_email(const ::std::string& value);
  inline void set_email(const char* value);
  inline void set_email(const char* value, size_t size);
  inline ::std::string* mutable_email();
  inline ::std::string* release_email();
  inline void set_allocated_email(::std::string* email);

  // repeated .tutorial.Person.PhoneNumber phone = 4;
  inline int phone_size() const;
  inline void clear_phone();
  static const int kPhoneFieldNumber = 4;
  inline const ::tutorial::Person_PhoneNumber& phone(int index) const;
  inline ::tutorial::Person_PhoneNumber* mutable_phone(int index);
  inline ::tutorial::Person_PhoneNumber* add_phone();
  inline const ::google::protobuf::RepeatedPtrField< ::tutorial::Person_PhoneNumber >&
      phone() const;
  inline ::google::protobuf::RepeatedPtrField< ::tutorial::Person_PhoneNumber >*
      mutable_phone();

  // @@protoc_insertion_point(class_scope:tutorial.Person)
 private:
  inline void set_has_name();
  inline void clear_has_name();
  inline void set_has_id();
  inline void clear_has_id();
  inline void set_has_email();
  inline void clear_has_email();

  ::google::protobuf::UnknownFieldSet _unknown_fields_;

  ::google::protobuf::uint32 _has_bits_[1];
  mutable int _cached_size_;
  ::std::string* name_;
  ::std::string* email_;
  ::google::protobuf::RepeatedPtrField< ::tutorial::Person_PhoneNumber > phone_;
  ::google::protobuf::int32 id_;
  friend void  protobuf_AddDesc_addressbook_2eproto();
  friend void protobuf_AssignDesc_addressbook_2eproto();
  friend void protobuf_ShutdownFile_addressbook_2eproto();

  void InitAsDefaultInstance();
  static Person* default_instance_;
};
// -------------------------------------------------------------------

class AddressBook : public ::google::protobuf::Message {
 public:
  AddressBook();
  virtual ~AddressBook();

  AddressBook(const AddressBook& from);

  inline AddressBook& operator=(const AddressBook& from) {
    CopyFrom(from);
    return *this;
  }

  inline const ::google::protobuf::UnknownFieldSet& unknown_fields() const {
    return _unknown_fields_;
  }

  inline ::google::protobuf::UnknownFieldSet* mutable_unknown_fields() {
    return &_unknown_fields_;
  }

  static const ::google::protobuf::Descriptor* descriptor();
  static const AddressBook& default_instance();

  void Swap(AddressBook* other);

  // implements Message ----------------------------------------------

  AddressBook* New() const;
  void CopyFrom(const ::google::protobuf::Message& from);
  void MergeFrom(const ::google::protobuf::Message& from);
  void CopyFrom(const AddressBook& from);
  void MergeFrom(const AddressBook& from);
  void Clear();
  bool IsInitialized() const;

  int ByteSize() const;
  bool MergePartialFromCodedStream(
      ::google::protobuf::io::CodedInputStream* input);
  void SerializeWithCachedSizes(
      ::google::protobuf::io::CodedOutputStream* output) const;
  ::google::protobuf::uint8* SerializeWithCachedSizesToArray(::google::protobuf::uint8* output) const;
  int GetCachedSize() const { return _cached_size_; }
  private:
  void SharedCtor();
  void SharedDtor();
  void SetCachedSize(int size) const;
  public:
  ::google::protobuf::Metadata GetMetadata() const;

  // nested types ----------------------------------------------------

  // accessors -------------------------------------------------------

  // repeated .tutorial.Person person = 1;
  inline int person_size() const;
  inline void clear_person();
  static const int kPersonFieldNumber = 1;
  inline const ::tutorial::Person& person(int index) const;
  inline ::tutorial::Person* mutable_person(int index);
  inline ::tutorial::Person* add_person();
  inline const ::google::protobuf::RepeatedPtrField< ::tutorial::Person >&
      person() const;
  inline ::google::protobuf::RepeatedPtrField< ::tutorial::Person >*
      mutable_person();

  // @@protoc_insertion_point(class_scope:tutorial.AddressBook)
 private:

  ::google::protobuf::UnknownFieldSet _unknown_fields_;

  ::google::protobuf::uint32 _has_bits_[1];
  mutable int _cached_size_;
  ::google::protobuf::RepeatedPtrField< ::tutorial::Person > person_;
  friend void  protobuf_AddDesc_addressbook_2eproto();
  friend void protobuf_AssignDesc_addressbook_2eproto();
  friend void protobuf_ShutdownFile_addressbook_2eproto();

  void InitAsDefaultInstance();
  static AddressBook* default_instance_;
};
// ===================================================================


// ===================================================================

// Person_PhoneNumber

// required string number = 1;
inline bool Person_PhoneNumber::has_number() const {
  return (_has_bits_[0] & 0x00000001u) != 0;
}
inline void Person_PhoneNumber::set_has_number() {
  _has_bits_[0] |= 0x00000001u;
}
inline void Person_PhoneNumber::clear_has_number() {
  _has_bits_[0] &= ~0x00000001u;
}
inline void Person_PhoneNumber::clear_number() {
  if (number_ != &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    number_->clear();
  }
  clear_has_number();
}
inline const ::std::string& Person_PhoneNumber::number() const {
  // @@protoc_insertion_point(field_get:tutorial.Person.PhoneNumber.number)
  return *number_;
}
inline void Person_PhoneNumber::set_number(const ::std::string& value) {
  set_has_number();
  if (number_ == &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    number_ = new ::std::string;
  }
  number_->assign(value);
  // @@protoc_insertion_point(field_set:tutorial.Person.PhoneNumber.number)
}
inline void Person_PhoneNumber::set_number(const char* value) {
  set_has_number();
  if (number_ == &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    number_ = new ::std::string;
  }
  number_->assign(value);
  // @@protoc_insertion_point(field_set_char:tutorial.Person.PhoneNumber.number)
}
inline void Person_PhoneNumber::set_number(const char* value, size_t size) {
  set_has_number();
  if (number_ == &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    number_ = new ::std::string;
  }
  number_->assign(reinterpret_cast<const char*>(value), size);
  // @@protoc_insertion_point(field_set_pointer:tutorial.Person.PhoneNumber.number)
}
inline ::std::string* Person_PhoneNumber::mutable_number() {
  set_has_number();
  if (number_ == &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    number_ = new ::std::string;
  }
  // @@protoc_insertion_point(field_mutable:tutorial.Person.PhoneNumber.number)
  return number_;
}
inline ::std::string* Person_PhoneNumber::release_number() {
  clear_has_number();
  if (number_ == &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    return NULL;
  } else {
    ::std::string* temp = number_;
    number_ = const_cast< ::std::string*>(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
    return temp;
  }
}
inline void Person_PhoneNumber::set_allocated_number(::std::string* number) {
  if (number_ != &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    delete number_;
  }
  if (number) {
    set_has_number();
    number_ = number;
  } else {
    clear_has_number();
    number_ = const_cast< ::std::string*>(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
  }
  // @@protoc_insertion_point(field_set_allocated:tutorial.Person.PhoneNumber.number)
}

// optional .tutorial.Person.PhoneType type = 2 [default = HOME];
inline bool Person_PhoneNumber::has_type() const {
  return (_has_bits_[0] & 0x00000002u) != 0;
}
inline void Person_PhoneNumber::set_has_type() {
  _has_bits_[0] |= 0x00000002u;
}
inline void Person_PhoneNumber::clear_has_type() {
  _has_bits_[0] &= ~0x00000002u;
}
inline void Person_PhoneNumber::clear_type() {
  type_ = 1;
  clear_has_type();
}
inline ::tutorial::Person_PhoneType Person_PhoneNumber::type() const {
  // @@protoc_insertion_point(field_get:tutorial.Person.PhoneNumber.type)
  return static_cast< ::tutorial::Person_PhoneType >(type_);
}
inline void Person_PhoneNumber::set_type(::tutorial::Person_PhoneType value) {
  assert(::tutorial::Person_PhoneType_IsValid(value));
  set_has_type();
  type_ = value;
  // @@protoc_insertion_point(field_set:tutorial.Person.PhoneNumber.type)
}

// -------------------------------------------------------------------

// Person

// required string name = 1;
inline bool Person::has_name() const {
  return (_has_bits_[0] & 0x00000001u) != 0;
}
inline void Person::set_has_name() {
  _has_bits_[0] |= 0x00000001u;
}
inline void Person::clear_has_name() {
  _has_bits_[0] &= ~0x00000001u;
}
inline void Person::clear_name() {
  if (name_ != &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    name_->clear();
  }
  clear_has_name();
}
inline const ::std::string& Person::name() const {
  // @@protoc_insertion_point(field_get:tutorial.Person.name)
  return *name_;
}
inline void Person::set_name(const ::std::string& value) {
  set_has_name();
  if (name_ == &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    name_ = new ::std::string;
  }
  name_->assign(value);
  // @@protoc_insertion_point(field_set:tutorial.Person.name)
}
inline void Person::set_name(const char* value) {
  set_has_name();
  if (name_ == &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    name_ = new ::std::string;
  }
  name_->assign(value);
  // @@protoc_insertion_point(field_set_char:tutorial.Person.name)
}
inline void Person::set_name(const char* value, size_t size) {
  set_has_name();
  if (name_ == &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    name_ = new ::std::string;
  }
  name_->assign(reinterpret_cast<const char*>(value), size);
  // @@protoc_insertion_point(field_set_pointer:tutorial.Person.name)
}
inline ::std::string* Person::mutable_name() {
  set_has_name();
  if (name_ == &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    name_ = new ::std::string;
  }
  // @@protoc_insertion_point(field_mutable:tutorial.Person.name)
  return name_;
}
inline ::std::string* Person::release_name() {
  clear_has_name();
  if (name_ == &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    return NULL;
  } else {
    ::std::string* temp = name_;
    name_ = const_cast< ::std::string*>(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
    return temp;
  }
}
inline void Person::set_allocated_name(::std::string* name) {
  if (name_ != &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    delete name_;
  }
  if (name) {
    set_has_name();
    name_ = name;
  } else {
    clear_has_name();
    name_ = const_cast< ::std::string*>(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
  }
  // @@protoc_insertion_point(field_set_allocated:tutorial.Person.name)
}

// required int32 id = 2;
inline bool Person::has_id() const {
  return (_has_bits_[0] & 0x00000002u) != 0;
}
inline void Person::set_has_id() {
  _has_bits_[0] |= 0x00000002u;
}
inline void Person::clear_has_id() {
  _has_bits_[0] &= ~0x00000002u;
}
inline void Person::clear_id() {
  id_ = 0;
  clear_has_id();
}
inline ::google::protobuf::int32 Person::id() const {
  // @@protoc_insertion_point(field_get:tutorial.Person.id)
  return id_;
}
inline void Person::set_id(::google::protobuf::int32 value) {
  set_has_id();
  id_ = value;
  // @@protoc_insertion_point(field_set:tutorial.Person.id)
}

// optional string email = 3;
inline bool Person::has_email() const {
  return (_has_bits_[0] & 0x00000004u) != 0;
}
inline void Person::set_has_email() {
  _has_bits_[0] |= 0x00000004u;
}
inline void Person::clear_has_email() {
  _has_bits_[0] &= ~0x00000004u;
}
inline void Person::clear_email() {
  if (email_ != &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    email_->clear();
  }
  clear_has_email();
}
inline const ::std::string& Person::email() const {
  // @@protoc_insertion_point(field_get:tutorial.Person.email)
  return *email_;
}
inline void Person::set_email(const ::std::string& value) {
  set_has_email();
  if (email_ == &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    email_ = new ::std::string;
  }
  email_->assign(value);
  // @@protoc_insertion_point(field_set:tutorial.Person.email)
}
inline void Person::set_email(const char* value) {
  set_has_email();
  if (email_ == &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    email_ = new ::std::string;
  }
  email_->assign(value);
  // @@protoc_insertion_point(field_set_char:tutorial.Person.email)
}
inline void Person::set_email(const char* value, size_t size) {
  set_has_email();
  if (email_ == &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    email_ = new ::std::string;
  }
  email_->assign(reinterpret_cast<const char*>(value), size);
  // @@protoc_insertion_point(field_set_pointer:tutorial.Person.email)
}
inline ::std::string* Person::mutable_email() {
  set_has_email();
  if (email_ == &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    email_ = new ::std::string;
  }
  // @@protoc_insertion_point(field_mutable:tutorial.Person.email)
  return email_;
}
inline ::std::string* Person::release_email() {
  clear_has_email();
  if (email_ == &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    return NULL;
  } else {
    ::std::string* temp = email_;
    email_ = const_cast< ::std::string*>(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
    return temp;
  }
}
inline void Person::set_allocated_email(::std::string* email) {
  if (email_ != &::google::protobuf::internal::GetEmptyStringAlreadyInited()) {
    delete email_;
  }
  if (email) {
    set_has_email();
    email_ = email;
  } else {
    clear_has_email();
    email_ = const_cast< ::std::string*>(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
  }
  // @@protoc_insertion_point(field_set_allocated:tutorial.Person.email)
}

// repeated .tutorial.Person.PhoneNumber phone = 4;
inline int Person::phone_size() const {
  return phone_.size();
}
inline void Person::clear_phone() {
  phone_.Clear();
}
inline const ::tutorial::Person_PhoneNumber& Person::phone(int index) const {
  // @@protoc_insertion_point(field_get:tutorial.Person.phone)
  return phone_.Get(index);
}
inline ::tutorial::Person_PhoneNumber* Person::mutable_phone(int index) {
  // @@protoc_insertion_point(field_mutable:tutorial.Person.phone)
  return phone_.Mutable(index);
}
inline ::tutorial::Person_PhoneNumber* Person::add_phone() {
  // @@protoc_insertion_point(field_add:tutorial.Person.phone)
  return phone_.Add();
}
inline const ::google::protobuf::RepeatedPtrField< ::tutorial::Person_PhoneNumber >&
Person::phone() const {
  // @@protoc_insertion_point(field_list:tutorial.Person.phone)
  return phone_;
}
inline ::google::protobuf::RepeatedPtrField< ::tutorial::Person_PhoneNumber >*
Person::mutable_phone() {
  // @@protoc_insertion_point(field_mutable_list:tutorial.Person.phone)
  return &phone_;
}

// -------------------------------------------------------------------

// AddressBook

// repeated .tutorial.Person person = 1;
inline int AddressBook::person_size() const {
  return person_.size();
}
inline void AddressBook::clear_person() {
  person_.Clear();
}
inline const ::tutorial::Person& AddressBook::person(int index) const {
  // @@protoc_insertion_point(field_get:tutorial.AddressBook.person)
  return person_.Get(index);
}
inline ::tutorial::Person* AddressBook::mutable_person(int index) {
  // @@protoc_insertion_point(field_mutable:tutorial.AddressBook.person)
  return person_.Mutable(index);
}
inline ::tutorial::Person* AddressBook::add_person() {
  // @@protoc_insertion_point(field_add:tutorial.AddressBook.person)
  return person_.Add();
}
inline const ::google::protobuf::RepeatedPtrField< ::tutorial::Person >&
AddressBook::person() const {
  // @@protoc_insertion_point(field_list:tutorial.AddressBook.person)
  return person_;
}
inline ::google::protobuf::RepeatedPtrField< ::tutorial::Person >*
AddressBook::mutable_person() {
  // @@protoc_insertion_point(field_mutable_list:tutorial.AddressBook.person)
  return &person_;
}


// @@protoc_insertion_point(namespace_scope)

}  // namespace tutorial

#ifndef SWIG
namespace google {
namespace protobuf {

template <> struct is_proto_enum< ::tutorial::Person_PhoneType> : ::google::protobuf::internal::true_type {};
template <>
inline const EnumDescriptor* GetEnumDescriptor< ::tutorial::Person_PhoneType>() {
  return ::tutorial::Person_PhoneType_descriptor();
}

}  // namespace google
}  // namespace protobuf
#endif  // SWIG

// @@protoc_insertion_point(global_scope)

#endif  // PROTOBUF_addressbook_2eproto__INCLUDED

 

生成的文件中有如下方法： 

// name
  inline bool has_name() const;
  inline void clear_name();
  inline const ::std::string& name() const;
  inline void set_name(const ::std::string& value);
  inline void set_name(const char* value);
  inline ::std::string* mutable_name();

  // id
  inline bool has_id() const;
  inline void clear_id();
  inline int32_t id() const;
  inline void set_id(int32_t value);

  // email
  inline bool has_email() const;
  inline void clear_email();
  inline const ::std::string& email() const;
  inline void set_email(const ::std::string& value);
  inline void set_email(const char* value);
  inline ::std::string* mutable_email();

  // phone
  inline int phone_size() const;
  inline void clear_phone();
  inline const ::google::protobuf::RepeatedPtrField< ::tutorial::Person_PhoneNumber >& phone() const;
  inline ::google::protobuf::RepeatedPtrField< ::tutorial::Person_PhoneNumber >* mutable_phone();
  inline const ::tutorial::Person_PhoneNumber& phone(int index) const;
  inline ::tutorial::Person_PhoneNumber* mutable_phone(int index);
  inline ::tutorial::Person_PhoneNumber* add_phone();

4、枚举与嵌套类

 

生成的代码包含一个PhoneType枚举。Person::PhoneType, Person:MOBILE, Person::HOME, Person:WORK.

 

编译器生成的嵌套类称为Person::PhoneNumber. 实际生成类为Person_PhoneNumber.

 

5、标准方法

 

bool IsInitialized() const:                确认required字段是否被设置

string DebugString() const:                返回消息的可读表示，用于调试

void CopyFrom(const Person& from):         使用给定消息值copy

void Clear():                              清除所有元素为空状态

6、解析与序列化

 

bool SerializeToString(string* output) const:        序列化消息，将存储字节的以string方式输出。注意字节是二进制，而非文本；

bool ParseFromString(const string& data):            解析给定的string     

bool SerializeToOstream(ostream* output) const:      写消息给定的c++  ostream中

bool ParseFromIstream(istream* input):               从给定的c++ istream中解析出消息

7、protobuf和 oo设计

不要继承生成类并在此基础上添加相应的行为

 

8、写消息

 

示例：它从一个文件中读取AddressBook，基于io添加一个新的Person，并将新的AddressBook写回文件。

#include <iostream>
#include <fstream>
#include <string>
#include "addressbook.pb.h"
using namespace std;

// This function fills in a Person message based on user input.
void PromptForAddress(tutorial::Person* person) {
  cout << "Enter person ID number: ";
  int id;
  cin >> id;
  person->set_id(id);
  cin.ignore(256, '\n');

  cout << "Enter name: ";
  getline(cin, *person->mutable_name());

  cout << "Enter email address (blank for none): ";
  string email;
  getline(cin, email);
  if (!email.empty()) {
    person->set_email(email);
  }

  while (true) {
    cout << "Enter a phone number (or leave blank to finish): ";
    string number;
    getline(cin, number);
    if (number.empty()) {
      break;
    }

    tutorial::Person::PhoneNumber* phone_number = person->add_phone();
    phone_number->set_number(number);

    cout << "Is this a mobile, home, or work phone? ";
    string type;
    getline(cin, type);
    if (type == "mobile") {
      phone_number->set_type(tutorial::Person::MOBILE);
    } else if (type == "home") {
      phone_number->set_type(tutorial::Person::HOME);
    } else if (type == "work") {
      phone_number->set_type(tutorial::Person::WORK);
    } else {
      cout << "Unknown phone type.  Using default." << endl;
    }
  }
}

// Main function:  Reads the entire address book from a file,
//   adds one person based on user input, then writes it back out to the same
//   file.
int main(int argc, char* argv[]) {
  // Verify that the version of the library that we linked against is
  // compatible with the version of the headers we compiled against.
  GOOGLE_PROTOBUF_VERIFY_VERSION;

  if (argc != 2) {
    cerr << "Usage:  " << argv[0] << " ADDRESS_BOOK_FILE" << endl;
    return -1;
  }

  tutorial::AddressBook address_book;

  {
    // Read the existing address book.
    fstream input(argv[1], ios::in | ios::binary);
    if (!input) {
      cout << argv[1] << ": File not found.  Creating a new file." << endl;
    } else if (!address_book.ParseFromIstream(&input)) {
      cerr << "Failed to parse address book." << endl;
      return -1;
    }
  }

  // Add an address.
  PromptForAddress(address_book.add_person());

  {
    // Write the new address book back to disk.
    fstream output(argv[1], ios::out | ios::trunc | ios::binary);
    if (!address_book.SerializeToOstream(&output)) {
      cerr << "Failed to write address book." << endl;
      return -1;
    }
  }

  // Optional:  Delete all global objects allocated by libprotobuf.
  google::protobuf::ShutdownProtobufLibrary();

  return 0;
}

 g++ addPerson.cpp  addressbook.pb.cc -o addPerson   -lpthread  -l protobuf

生成addPerson.

运行./addPerson addressbook1

 

注意使用GOOGLE_PROTOBUF_VERIFY_VERSION宏。每一个.pb.cc文件在启动时都将自动调用该宏。

 

注意在程序结尾处调用ShutdownProtobufLibrary()。

 

9、读消息 

#include <iostream>
#include <fstream>
#include <string>
#include "addressbook.pb.h"
using namespace std;

// Iterates though all people in the AddressBook and prints info about them.
void ListPeople(const tutorial::AddressBook& address_book) {
  for (int i = 0; i < address_book.person_size(); i++) {
    const tutorial::Person& person = address_book.person(i);

    cout << "Person ID: " << person.id() << endl;
    cout << "  Name: " << person.name() << endl;
    if (person.has_email()) {
      cout << "  E-mail address: " << person.email() << endl;
    }

    for (int j = 0; j < person.phone_size(); j++) {
      const tutorial::Person::PhoneNumber& phone_number = person.phone(j);

      switch (phone_number.type()) {
        case tutorial::Person::MOBILE:
          cout << "  Mobile phone #: ";
          break;
        case tutorial::Person::HOME:
          cout << "  Home phone #: ";
          break;
        case tutorial::Person::WORK:
          cout << "  Work phone #: ";
          break;
      }
      cout << phone_number.number() << endl;
    }
  }
}

// Main function:  Reads the entire address book from a file and prints all
//   the information inside.
int main(int argc, char* argv[]) {
  // Verify that the version of the library that we linked against is
  // compatible with the version of the headers we compiled against.
  GOOGLE_PROTOBUF_VERIFY_VERSION;

  if (argc != 2) {
    cerr << "Usage:  " << argv[0] << " ADDRESS_BOOK_FILE" << endl;
    return -1;
  }

  tutorial::AddressBook address_book;

  {
    // Read the existing address book.
    fstream input(argv[1], ios::in | ios::binary);
    if (!address_book.ParseFromIstream(&input)) {
      cerr << "Failed to parse address book." << endl;
      return -1;
    }
  }

  ListPeople(address_book);

  // Optional:  Delete all global objects allocated by libprotobuf.
  google::protobuf::ShutdownProtobufLibrary();

  return 0;
}

g++ readPerson.cpp  addressbook.pb.cc -o readPerson   -lpthread  -l protobuf

运行:

./readPerson addressbook1
Person ID: 1
Name: suming
E-mail address: gz
Mobile phone #: 13631279712
Home phone #: 4578
Work phone #: 963
Work phone #: 65

10、扩展protobuf

 

如果希望向后兼容，必须遵循：

a、不必更改tag数

b、不必添加或删除任何required字段

c、可以删除optional或repeated字段

d、可以添加新的optional或repeated字段，但你必须使用新的tag数。

 

11、优化

c++的protobuf库，已经极大地优化了。合理使用可以改善性能。

a、如果可能，复用message对象。

b、关于多线程的内存分配器

 

12、高级用法

 

protobuf的消息类的一个关键特性是，反射(reflection)。可以使用xml或json来实现。参考。

 

 

================================================================

常见问题：

1、undefined reference to `pthread_once' 

使用-lpthread:

 

2、error while loading shared libraries: libprotobuf.so.7: cannot open shared object file: No such file or directory

使用-Wl,-Bstatic -lprotobuf -Wl,-Bdynamic -lpthread

 

 

参考：http://blog.youkuaiyun.com/zmzsoftware/article/details/17356199

 

一个简单的例子：

helloworld.proto

package hw;
message helloworld
{
    required int32 id=1;//id
    required string str=2;//str
    optional int32  opt=3;//opt

}

protoc -I=. --cpp_out=.   helloworld.proto

写序列化消息的进程

#include"helloworld.pb.h"
#include<iostream>
#include<fstream>
using namespace std;

int main()
{
    hw::helloworld msg1;
    msg1.set_id(101);
    msg1.set_str("hello");
    
    fstream output("./log",ios::out| ios::trunc | ios::binary);
    if(! msg1.SerializeToOstream(&output))
    {
        cerr<<"Failed to write msg!"<<endl;
        return -1;
    }
    
    return 0;
}

编译 write.cc 

 g++  msg.pb.cc write.cc -o write  `pkg-config --cflags --libs protobuf` -lpthread

 

执行write 

./write， 可以看到生成了log文件

root@iZ23onhpqvwZ:~/ms/protobuf/helloworld# xxd log 查看log二进制
0000000: 0865 1205 6865 6c6c 6f .e..hello

 

 

写反序列化的进程

reader.cc

#include"helloworld.pb.h"
#include<iostream>
#include<fstream>
using namespace std;

void ListMsg(const hw::helloworld &msg)
{
    cout<<msg.id()<<endl;
    cout<<msg.str()<<endl;
}

int main(int argc,char **argv)
{
    hw::helloworld msg1;
    msg1.set_id(101);
    msg1.set_str("hello");
    
    fstream input("./log",ios::in | ios::binary);
    if(!msg1.ParseFromIstream(&input))
    {
       cerr<<"failed to parsed address book!";
       return -1;
    }
    
    ListMsg(msg1);
    return 0;
}

编译：g++  msg.pb.cc reader.cc -o reader  `pkg-config --cflags --libs protobuf` -lpthread

执行./reader 输出 ：

101

hello

 

makefile文件：

all:write reader

clean:
    rm -f write reader helloworld.*.cc helloworld.*.h *.o log
    
proto_msg:
    protoc -I=. --cpp_out=.  helloworld.proto
    
write:helloworld.pb.cc write.cpp 
    g++ $^ -o  $@ -l protobuf -lpthread
reader:helloworld.pb.cc reader.cpp
    g++ $^ -o  $@ -l protobuf -lpthread
    

参考了:http://www.cppblog.com/colorful/archive/2012/05/05/173761.html

 $@--目标文件，$^--所有的依赖文件，$<--第一个依赖文件。

protobuf 官方只有java、c++、Python的支持。

 

 ----------------------

一个例子：

关于Windows环境下protobuf初步学习指南

http://wenku.baidu.com/link?url=yAY8KF5lLV1LJa_yFwTygoizdUAZDB-l2bLa6IUN79q-xiogW8se1VKew9DIsSAa9o02m7F2XJPFananREd4jrxuUaVhan34Aw7qwGVr61K

 

讲解如何配置vs的：

VS2008下创建一个工程ProtoBuf，需要添加protobuf的头文件和lib文件。 
A．添加头文件操作：右击项目属性配置属性C/C++常规，右边附加包含目录。具体路径：H:\protobuf-2.4.1\protobuf-2.4.1\src 
B．添加库文件（lib）操作：右击项目属性配置属性链接器常规，右边附加库目录。具体路径：H:\protobuf-2.4.1\protobuf-2.4.1\vsprojects\Debug 
把person.pb.h和person.ph.cc放到工程ProtoBuf相应的头文件夹和源文件夹中

 

#include<iostream>
#include"helloworld.pb.h"

#pragma comment(lib,"libprotobuf.lib")
#pragma comment(lib,"libprotoc.lib")

using namespace std;
using namespace Im;


int main(int argc, char **argv)
{
    helloworld msg1;
    msg1.set_id(100);
    msg1.set_str("sd");

    cout << msg1.id();
    cout << msg1.str();

}

如果不想写

#pragma comment(lib,"libprotobuf.lib")
#pragma comment(lib,"libprotoc.lib")

有一种办法，项目配置-》链接器-》输入-》附加依赖性，增加

libprotobuf.lib

libprotoc.lib 也行。

http://my.oschina.net/cxh3905/blog/293000

http://blog.youkuaiyun.com/wangji163163/article/details/4455085

 

 

http://blog.sina.com.cn/s/blog_559f6ffc0101bo7u.html

protobuf socket:http://blog.youkuaiyun.com/monkey_d_meng/article/details/5894910