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

protobuf底層使用C++實現的.但現在已經支持很多的語言使用了.目前支持:C++,java,python,objective-c,c#, javascript, ruby, go, php, Dart. 在這里講protobuf在go中的使用.我使用的環境是ubuntu 16.04

在使用之前需要安裝proto的基礎包.基礎包是C++編寫的，所以需要用到編譯Ｃ++一些常規的環境，這里不具體介紹．

安裝go的環境

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

獲取之后進入相應的文件夾，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．

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

下面我們就看一個使用的例子，先寫一個proto的原文件,這里以學生以及和學生管理的考試成績為例子:

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.

使用命令進行轉換:

protoc --go_out=. Studentlist.proto

當轉換完成會生成如下的文件:

// Code generated by protoc-gen-go. DO NOT EDIT. // source: Studentlist.protopackage pbimport (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 packagetype 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.InternalMessageInfofunc (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.InternalMessageInfofunc (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.InternalMessageInfofunc (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 FileDescriptorProto0x1f, 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里面先對數據進行序列化,然后再反序列化.

package mainimport ("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.Studentlisterr = 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())}} }

輸出結果如下:

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

這里需要注意的地方:

1.在proto文件中定義的字段如果首字母是小寫,那么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,需要使用proto.String轉為指針類型. 這個你可以在轉換后的文件中可以看到.

作者：amei 鏈接：http://114.116.145.166:5897/blogs/amei/articles/2019/04/02/1554195518207

轉載于:https://my.oschina.net/u/1013544/blog/3031466

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