protocol buffers是谷歌的语言中立、平台中立、可扩展的结构化数据序列化机制——XML，但更小、更快、更简单。您可以一次定义数据的结构化方式，然后可以使用特殊生成的源代码轻松地使用各种语言（C++/ C#/ Dart/ Go/ Java/ Kotlin/ Python）在各种数据流中写入和读取结构化数据。
最简单的方式：
sudo apt install protobuf-compiler
如果你想使用最新版，安装教程可以参考C++ Installation官网
我用的是WSL，对于Linux类似，如果环境上有问题可以参考：【从零开始】在Windows中使用Linux——在WSL使用CLion、IDEA、PyCharm（安装到建立工程）——更新于2021.12
我们从官网下载最新的Download Protocol Buffers（官方用例）作为例子如下：
首先打开IDEA创建工程：
在当前目录创建文件addressbook.proto：
// See README.txt for information and build instructions.
//
// Note: START and END tags are used in comments to define sections used in
// tutorials. They are not part of the syntax for Protocol Buffers.
//
// To get an in-depth walkthrough of this file and the related examples, see:
// https://developers.google.com/protocol-buffers/docs/tutorials
// [START declaration]
syntax = "proto3";
package tutorial;
import "google/protobuf/timestamp.proto";
// [END declaration]
// [START java_declaration]
option java_multiple_files = true;
option java_package = "com.example.tutorial.protos";
option java_outer_classname = "AddressBookProtos";
// [END java_declaration]
// [START csharp_declaration]
option csharp_namespace = "Google.Protobuf.Examples.AddressBook";
// [END csharp_declaration]
// [START go_declaration]
option go_package = "../tutorial";
// [END go_declaration]
// [START messages]
message Person {
string name = 1;
int32 id = 2; // Unique ID number for this person.
string email = 3;
enum PhoneType {
MOBILE = 0;
HOME = 1;
WORK = 2;
}
message PhoneNumber {
string number = 1;
PhoneType type = 2;
}
repeated PhoneNumber phones = 4;
google.protobuf.Timestamp last_updated = 5;
}
// Our address book file is just one of these.
message AddressBook {
repeated Person people = 1;
}
// [END messages]
在src目录下创建：
文件AddPerson.java：
// See README.txt for information and build instructions.
import com.example.tutorial.protos.AddressBook;
import com.example.tutorial.protos.Person;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.IOException;
import java.io.PrintStream;
class AddPerson {
// This function fills in a Person message based on user input.
static Person PromptForAddress(BufferedReader stdin, PrintStream stdout) throws IOException {
Person.Builder person = Person.newBuilder();
stdout.print("Enter person ID: ");
person.setId(Integer.valueOf(stdin.readLine()));
stdout.print("Enter name: ");
person.setName(stdin.readLine());
stdout.print("Enter email address (blank for none): ");
String email = stdin.readLine();
if (email.length() > 0) {
person.setEmail(email);
}
while (true) {
stdout.print("Enter a phone number (or leave blank to finish): ");
String number = stdin.readLine();
if (number.length() == 0) {
break;
}
Person.PhoneNumber.Builder phoneNumber =
Person.PhoneNumber.newBuilder().setNumber(number);
stdout.print("Is this a mobile, home, or work phone? ");
String type = stdin.readLine();
if (type.equals("mobile")) {
phoneNumber.setType(Person.PhoneType.MOBILE);
} else if (type.equals("home")) {
phoneNumber.setType(Person.PhoneType.HOME);
} else if (type.equals("work")) {
phoneNumber.setType(Person.PhoneType.WORK);
} else {
stdout.println("Unknown phone type. Using default.");
}
person.addPhones(phoneNumber);
}
return person.build();
}
// 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.
public static void main(String[] args) throws Exception {
if (args.length != 1) {
System.err.println("Usage: AddPerson ADDRESS_BOOK_FILE");
System.exit(-1);
}
AddressBook.Builder addressBook = AddressBook.newBuilder();
// Read the existing address book.
try {
FileInputStream input = new FileInputStream(args[0]);
try {
addressBook.mergeFrom(input);
} finally {
try {
input.close();
} catch (Throwable ignore) {
}
}
} catch (FileNotFoundException e) {
System.out.println(args[0] + ": File not found. Creating a new file.");
}
// Add an address.
addressBook.addPeople(
PromptForAddress(new BufferedReader(new InputStreamReader(System.in)),
System.out));
// Write the new address book back to disk.
FileOutputStream output = new FileOutputStream(args[0]);
try {
addressBook.build().writeTo(output);
} finally {
output.close();
}
}
}
文件ListPeople.java：
// See README.txt for information and build instructions.
import com.example.tutorial.protos.AddressBook;
import com.example.tutorial.protos.Person;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.PrintStream;
class ListPeople {
// Iterates though all people in the AddressBook and prints info about them.
static void Print(AddressBook addressBook) {
for (Person person : addressBook.getPeopleList()) {
System.out.println("Person ID: " + person.getId());
System.out.println(" Name: " + person.getName());
if (!person.getEmail().isEmpty()) {
System.out.println(" E-mail address: " + person.getEmail());
}
for (Person.PhoneNumber phoneNumber : person.getPhonesList()) {
switch (phoneNumber.getType()) {
case MOBILE:
System.out.print(" Mobile phone #: ");
break;
case HOME:
System.out.print(" Home phone #: ");
break;
case WORK:
System.out.print(" Work phone #: ");
break;
default:
System.out.println(" Unknown phone #: ");
break;
}
System.out.println(phoneNumber.getNumber());
}
}
}
// Main function: Reads the entire address book from a file and prints all
// the information inside.
public static void main(String[] args) throws Exception {
if (args.length != 1) {
System.err.println("Usage: ListPeople ADDRESS_BOOK_FILE");
System.exit(-1);
}
// Read the existing address book.
AddressBook addressBook =
AddressBook.parseFrom(new FileInputStream(args[0]));
Print(addressBook);
}
}
在IDEA左下角打开Terminal：
输入：
protoc -I=./ --java_out=./src addressbook.proto
这时候我们会发现生成了以下文件：
我们需要导入一下protobuf的jar包，这里可以使用maven：
<dependency>
<groupId>com.google.protobuf</groupId>
<artifactId>protobuf-java</artifactId>
<version>3.19.1</version>
</dependency>
也可以从这里下载com/google/protobuf/protobuf-java/3.19.1
下载完成后放入lib文件夹：
在IDEA里，File | Project Structure | Project Settings | Modules | Dependencies：
这样也可以导入jar包。
之后，Run | Edit configuration 里添加 Application
我们点选run：
然后在Run窗口里输入你想存入的数据：
同样的，Run | Edit configuration 里添加 Application：
我们点选run：
在Run窗口中会打印出我们刚才存入的数据：
