protobuf在go中的應用

時間  2019-12-07
標籤 protobuf 應用 欄目 微服務 简体版
原文   原文鏈接

protobuf是一個跨語言的傳輸協議格式,其功能和json相似. protobuf和json不一樣的是proto使用二進制進行傳輸,速度上會比json效率高. 可是在可讀性上比json差.javascript

protobuf底層使用C++實現的.但如今已經支持不少的語言使用了.目前支持:C++,java,python,objective-c,c#, javascript, ruby, go, php, Dart. 在這裏講protobuf在go中的使用.我使用的環境是ubuntu 16.04php

在使用以前須要安裝proto的基礎包.基礎包是C++編寫的，因此須要用到編譯Ｃ++一些常規的環境，這裏不具體介紹．java

安裝go的環境python

再者獲取go相關的插件包：go get -u github.com/golang/protobufgit

獲取以後進入相應的文件夾，使用go build , go install進行編譯和安裝．使用命令：proto --version測試是否成功安裝．github

chenmei@bogon:~/go/src/test/protobuf$ protoc --version 
libprotoc 2.6.1

下面咱們就看一個使用的例子，先寫一個proto的原文件,這裏以學生以及和學生管理的考試成績爲例子:golang

syntax = "proto2";
package pb;

message Course {
    required string name = 1;
    required int32 score = 2;
}
message Student {
    required int32 UUID = 1;
    required string Username = 2;
    repeated Course courses = 3;
}

message Studentlist {
    repeated Student students = 1;
}

上面就定義了課程,學生,以及學生的列表這幾個結構.objective-c

使用命令進行轉換:json

protoc --go_out=. Studentlist.proto

當轉換完成會生成以下的文件:ubuntu

// Code generated by protoc-gen-go. DO NOT EDIT.
// source: Studentlist.proto

package pb

import (
	fmt "fmt"
	proto "github.com/golang/protobuf/proto"
	math "math"
)

// Reference imports to suppress errors if they are not otherwise used.
var _ = proto.Marshal
var _ = fmt.Errorf
var _ = math.Inf

// This is a compile-time assertion to ensure that this generated file
// is compatible with the proto package it is being compiled against.
// A compilation error at this line likely means your copy of the
// proto package needs to be updated.
const _ = proto.ProtoPackageIsVersion3 // please upgrade the proto package

type Course struct {
	Name                 *string  `protobuf:"bytes,1,req,name=name" json:"name,omitempty"`
	Score                *int32   `protobuf:"varint,2,req,name=score" json:"score,omitempty"`
	XXX_NoUnkeyedLiteral struct{} `json:"-"`
	XXX_unrecognized     []byte   `json:"-"`
	XXX_sizecache        int32    `json:"-"`
}

func (m *Course) Reset()         { *m = Course{} }
func (m *Course) String() string { return proto.CompactTextString(m) }
func (*Course) ProtoMessage()    {}
func (*Course) Descriptor() ([]byte, []int) {
	return fileDescriptor_14fc7c21f335a148, []int{0}
}

func (m *Course) XXX_Unmarshal(b []byte) error {
	return xxx_messageInfo_Course.Unmarshal(m, b)
}
func (m *Course) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
	return xxx_messageInfo_Course.Marshal(b, m, deterministic)
}
func (m *Course) XXX_Merge(src proto.Message) {
	xxx_messageInfo_Course.Merge(m, src)
}
func (m *Course) XXX_Size() int {
	return xxx_messageInfo_Course.Size(m)
}
func (m *Course) XXX_DiscardUnknown() {
	xxx_messageInfo_Course.DiscardUnknown(m)
}

var xxx_messageInfo_Course proto.InternalMessageInfo

func (m *Course) GetName() string {
	if m != nil && m.Name != nil {
		return *m.Name
	}
	return ""
}

func (m *Course) GetScore() int32 {
	if m != nil && m.Score != nil {
		return *m.Score
	}
	return 0
}

type Student struct {
	UUID                 *int32    `protobuf:"varint,1,req,name=UUID" json:"UUID,omitempty"`
	Username             *string   `protobuf:"bytes,2,req,name=Username" json:"Username,omitempty"`
	Courses              []*Course `protobuf:"bytes,3,rep,name=courses" json:"courses,omitempty"`
	XXX_NoUnkeyedLiteral struct{}  `json:"-"`
	XXX_unrecognized     []byte    `json:"-"`
	XXX_sizecache        int32     `json:"-"`
}

func (m *Student) Reset()         { *m = Student{} }
func (m *Student) String() string { return proto.CompactTextString(m) }
func (*Student) ProtoMessage()    {}
func (*Student) Descriptor() ([]byte, []int) {
	return fileDescriptor_14fc7c21f335a148, []int{1}
}

func (m *Student) XXX_Unmarshal(b []byte) error {
	return xxx_messageInfo_Student.Unmarshal(m, b)
}
func (m *Student) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
	return xxx_messageInfo_Student.Marshal(b, m, deterministic)
}
func (m *Student) XXX_Merge(src proto.Message) {
	xxx_messageInfo_Student.Merge(m, src)
}
func (m *Student) XXX_Size() int {
	return xxx_messageInfo_Student.Size(m)
}
func (m *Student) XXX_DiscardUnknown() {
	xxx_messageInfo_Student.DiscardUnknown(m)
}

var xxx_messageInfo_Student proto.InternalMessageInfo

func (m *Student) GetUUID() int32 {
	if m != nil && m.UUID != nil {
		return *m.UUID
	}
	return 0
}

func (m *Student) GetUsername() string {
	if m != nil && m.Username != nil {
		return *m.Username
	}
	return ""
}

func (m *Student) GetCourses() []*Course {
	if m != nil {
		return m.Courses
	}
	return nil
}

type Studentlist struct {
	Students             []*Student `protobuf:"bytes,1,rep,name=students" json:"students,omitempty"`
	XXX_NoUnkeyedLiteral struct{}   `json:"-"`
	XXX_unrecognized     []byte     `json:"-"`
	XXX_sizecache        int32      `json:"-"`
}

func (m *Studentlist) Reset()         { *m = Studentlist{} }
func (m *Studentlist) String() string { return proto.CompactTextString(m) }
func (*Studentlist) ProtoMessage()    {}
func (*Studentlist) Descriptor() ([]byte, []int) {
	return fileDescriptor_14fc7c21f335a148, []int{2}
}

func (m *Studentlist) XXX_Unmarshal(b []byte) error {
	return xxx_messageInfo_Studentlist.Unmarshal(m, b)
}
func (m *Studentlist) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
	return xxx_messageInfo_Studentlist.Marshal(b, m, deterministic)
}
func (m *Studentlist) XXX_Merge(src proto.Message) {
	xxx_messageInfo_Studentlist.Merge(m, src)
}
func (m *Studentlist) XXX_Size() int {
	return xxx_messageInfo_Studentlist.Size(m)
}
func (m *Studentlist) XXX_DiscardUnknown() {
	xxx_messageInfo_Studentlist.DiscardUnknown(m)
}

var xxx_messageInfo_Studentlist proto.InternalMessageInfo

func (m *Studentlist) GetStudents() []*Student {
	if m != nil {
		return m.Students
	}
	return nil
}

func init() {
	proto.RegisterType((*Course)(nil), "pb.Course")
	proto.RegisterType((*Student)(nil), "pb.Student")
	proto.RegisterType((*Studentlist)(nil), "pb.Studentlist")
}

func init() { proto.RegisterFile("Studentlist.proto", fileDescriptor_14fc7c21f335a148) }

var fileDescriptor_14fc7c21f335a148 = []byte{
	// 158 bytes of a gzipped FileDescriptorProto
	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0xe2, 0x12, 0x0c, 0x2e, 0x29, 0x4d,
	0x49, 0xcd, 0x2b, 0xc9, 0xc9, 0x2c, 0x2e, 0xd1, 0x2b, 0x28, 0xca, 0x2f, 0xc9, 0x17, 0x62, 0x2a,
	0x48, 0x52, 0x52, 0xe5, 0x62, 0x73, 0xce, 0x2f, 0x2d, 0x2a, 0x4e, 0x15, 0xe2, 0xe1, 0x62, 0xc9,
	0x4b, 0xcc, 0x4d, 0x95, 0x60, 0x54, 0x60, 0xd2, 0xe0, 0x14, 0xe2, 0xe5, 0x62, 0x2d, 0x4e, 0xce,
	0x2f, 0x4a, 0x95, 0x60, 0x52, 0x60, 0xd2, 0x60, 0x55, 0x72, 0xe3, 0x62, 0x87, 0xea, 0x07, 0xa9,
	0x0b, 0x0d, 0xf5, 0x74, 0x01, 0xab, 0x63, 0x15, 0x12, 0xe0, 0xe2, 0x08, 0x2d, 0x4e, 0x2d, 0x02,
	0xeb, 0x64, 0x02, 0xeb, 0x94, 0xe6, 0x62, 0x4f, 0x06, 0x9b, 0x58, 0x2c, 0xc1, 0xac, 0xc0, 0xac,
	0xc1, 0x6d, 0xc4, 0xa5, 0x57, 0x90, 0xa4, 0x07, 0xb1, 0x44, 0x49, 0x87, 0x8b, 0x1b, 0xc9, 0x1d,
	0x42, 0xb2, 0x5c, 0x1c, 0xc5, 0x10, 0x6e, 0xb1, 0x04, 0x23, 0x58, 0x31, 0x37, 0x48, 0x31, 0x54,
	0x09, 0x20, 0x00, 0x00, 0xff, 0xff, 0x66, 0x6d, 0x7d, 0x4c, 0xb4, 0x00, 0x00, 0x00,
}

下面看main.go的寫法,在main裏面先對數據進行序列化,而後再反序列化.

package main

import (
    "fmt"
    "test/protobuf/pb"
    "github.com/golang/protobuf/proto"
)

func main() {
    course11 := pb.Course{
        Name: proto.String("math"),
        Score: proto.Int32(99),
    }
    course12 := pb.Course {
        Name: proto.String("english"),
        Score: proto.Int32(90),
    }

    course21 := pb.Course{
        Name: proto.String("math"),
        Score: proto.Int32(94),
    }
    course22 := pb.Course {
        Name: proto.String("english"),
        Score: proto.Int32(95),
    }

    student1 := pb.Student {
        UUID: proto.Int32(1),
        Username: proto.String("mei.chen"),
        Courses: []*pb.Course{&course11, &course12},
    }
    student2 := pb.Student {
        UUID: proto.Int32(2),
        Username: proto.String("he.he"),
        Courses: []*pb.Course{&course21, &course22},
    }

    students := pb.Studentlist {
        Students: []*pb.Student{&student1,&student2},
    }
    //序列化:
    data, err := proto.Marshal(&students)
    if err != nil {
        fmt.Println("marshal error", err)
    }
    fmt.Println("marshal data:",data)

    //反序列化
    var list pb.Studentlist
    err = proto.Unmarshal(data, &list)
    if err != nil {
        fmt.Println("unmarshal error:",err)
    }
    for _, student := range list.Students {
        fmt.Println("------------------------------------------")
        fmt.Println("sudent name: ",student.GetUsername())
        for _, course := range student.Courses {
            fmt.Println("course: ",course.GetName())
            fmt.Println("score: ",course.GetScore())
        }

    }
}

輸出結果以下:

marshal data: [10 35 8 1 18 8 109 101 105 46 99 104 101 110 26 8 10 4 109 97 116 104 16 99 26 11 10 7 101 110 103 108 105 115 104 16 90 10 32 8 2 18 5 104 101 46 104 101 26 8 10 4 109 97 116 104 16 94 26 11 10 7 101 110 103 108 105 115 104 16 95]
------------------------------------------
sudent name:  mei.chen
course:  math
score:  99
course:  english
score:  90
------------------------------------------
sudent name:  he.he
course:  math
score:  94
course:  english
score:  95

這裏須要注意的地方:

1.在proto文件中定義的字段若是首字母是小寫,那麼在轉換的時候會變成大寫.

2.在proto中定義的類型其實都是指針,例如string,須要使用proto.String轉爲指針類型. 這個你能夠在轉換後的文件中能夠看到.

做者：amei 連接：http://114.116.145.166:5897/blogs/amei/articles/2019/04/02/1554195518207

相關文章
相關標籤/搜索
每日一句
    每一个你不满意的现在，都有一个你没有努力的曾经。
本站公眾號
   歡迎關注本站公眾號,獲取更多信息
聯繫我們 最近搜索 最新文章 沪ICP备13005482号-10 MyBatis教程 SQL 教程 MySQL教程 Java 教程 Thymeleaf 教程 Hibernate教程 Spring教程 Redis教程