Spring Boot项目中使用Protobuf序列化
1. Protobuf 简介与优势
Protocol Buffers(Protobuf)是 Google 推出的一种语言无关、平台无关、可扩展 的二进制序列化协议。相比 JSON/XML,它通常可将数据体积压缩 50% 以上 (极端场景达 90%),解析速度比反射式 JSON 解析器快 5-10 倍 ,同时内置 Schema Evolution 机制,确保新旧服务无缝升级。特别适用于微服务通信、消息队列、IoT 与移动端等对性能及带宽敏感的场景。
2. 项目结构与依赖配置
2.1 项目结构说明
bash
src
│ ├── main
│ │ ├── java
│ │ │ └── cn
│ │ │ └── protobuf
│ │ │ ├── demo
│ │ │ │ └── UserProtosSamples.java # 示例代码
│ │ │ ├── proto
│ │ │ │ └── UserProtos.java # 编译生成的类
│ │ │ └── ProtobufApplication.java # Spring Boot入口
│ │ ├── proto
│ │ │ └── user.proto # Protobuf schema定义
│ │ └── resources
│ │ └── bootstrap.yml # 配置文件
│ └── test
│ └── java
pom.xml
2.2 Maven 依赖与插件配置
xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.example</groupId>
<artifactId>springboot-protobuf</artifactId>
<version>1.0-SNAPSHOT</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>3.0.2</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<maven.compiler.source>17</maven.compiler.source>
<maven.compiler.target>17</maven.compiler.target>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<spring-boot.version>3.0.2</spring-boot.version>
<spring-cloud.version>2022.0.0</spring-cloud.version>
<spring-cloud-alibaba.version>2022.0.0.0</spring-cloud-alibaba.version>
<protobuf.version>3.25.6</protobuf.version>
<protobuf-plugin.version>0.6.1</protobuf-plugin.version>
</properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>${spring-boot.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-alibaba-dependencies</artifactId>
<version>${spring-cloud-alibaba.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-bootstrap</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<!--任何使用protobuf的项目都必须引入-->
<dependency>
<groupId>com.google.protobuf</groupId>
<artifactId>protobuf-java</artifactId>
<version>${protobuf.version}</version>
</dependency>
<!--需要把protobuf对象直接转成JSON、或接收JSON再转回protobuf时使用-->
<dependency>
<groupId>com.google.protobuf</groupId>
<artifactId>protobuf-java-util</artifactId>
<version>${protobuf.version}</version>
</dependency>
</dependencies>
<build>
<finalName>springboot-protobuf</finalName>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.10.1</version>
<configuration>
<source>17</source>
<target>17</target>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>${spring-boot.version}</version>
<configuration>
<mainClass>cn.protobuf.ProtobufApplication</mainClass>
</configuration>
<executions>
<execution>
<id>repackage</id>
<goals>
<goal>repackage</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.xolstice.maven.plugins</groupId>
<artifactId>protobuf-maven-plugin</artifactId>
<version>0.6.1</version>
<configuration>
<!--告诉插件去哪里找 .proto 源文件${basedir}就是Maven项目的根目录,因此它会扫描 <项目根>/src/main/proto/*.proto-->
<protoSourceRoot>${basedir}/src/main/proto</protoSourceRoot>
<!--自动下载并调用 protoc 编译器-->
<protocArtifact>com.google.protobuf:protoc:${protobuf.version}:exe:${os.detected.classifier}</protocArtifact>
<!--自动下载gRPC Java 插件(protoc-gen-grpc-java)用于根据 .proto 中的 service 定义生成 gRPC 服务端/客户端的接口和桩代码(Stub) 同样根据操作系统自动选可执行文件-->
<pluginArtifact>io.grpc:protoc-gen-grpc-java:1.43.1:exe:${os.detected.classifier}</pluginArtifact>
<!--生成的 Java 源码输出目录 这里设为 src/main/java, 生成的类会跟手写代码放在一起;IDE 刷新后即可直接引用 -->
<outputDirectory>src/main/java</outputDirectory>
<!--构建前不清空输出目录,避免误删你已有的源码 设为 true 则每次都会先删再生成-->
<clearOutputDirectory>false</clearOutputDirectory>
<!--给gRPC插件起一个内部id,protobuf-maven-plugin 用它区分不同自定义插件,可保持默认即可-->
<pluginId>grpc-java</pluginId>
</configuration>
<executions>
<execution>
<goals>
<goal>compile</goal>
<goal>compile-custom</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
<resources>
<resource>
<directory>src/main/java</directory>
<excludes>
<exclude>**/*.java</exclude>
</excludes>
</resource>
<resource>
<directory>src/main/resources</directory>
</resource>
</resources>
<!--
让 Maven 在构建最开始时自动检测当前操作系统和 CPU 架构,并生成一组以 os.detected.* 开头的属性,供后续插件或依赖使用
为了 protobuf-maven-plugin 里的这两行占位符${os.detected.classifier}
没有 os-maven-plugin,${os.detected.classifier} 无法解析.Maven 就会报错找不到对应平台的可执行文件
-->
<extensions>
<extension>
<groupId>kr.motd.maven</groupId>
<artifactId>os-maven-plugin</artifactId>
<version>1.7.1</version>
</extension>
</extensions>
</build>
</project>
2.3 其他文件代码
① user.proto
ini
syntax = "proto3"; //声明proto3语法版本(最新主流版本)
package cn.proto.demo; //proto层面的包名,主要用于避免不同,proto文件里消息重名
option java_package = "cn.protobuf.proto"; //Java真正生成的包路径,编译后生成的类都在这个Java包下
option java_outer_classname = "UserProtos"; //生成的最外层Java类名,默认会把所有消息放在UserProtos.java里
//定义一个地址结构体,含3个字符串字段。
//数字1、2、3 是字段编号(二进制里用来识别字段,必须唯一且尽量小)
message Address {
string street = 1;
string city = 2;
string zip = 3;
}
message User {
//基本标量类型:int64、string、int32
int64 id = 1;
string name = 2;
string email = 3;
int32 age = 4;
//repeated → 表示数组/List 在Java中会变成List<Address>
repeated Address addresses = 5;
//同样是数组,但加了[packed = true]:把所有int64打包成紧凑二进制,节省空间Java中仍是List<Long>
repeated int64 scores = 6 [packed = true];
//map类型,等价于Java的 Map<String, String> map<string, string> ext = 7;
}
② ProtobufApplication.java
java
package cn.protobuf;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class ProtobufApplication {
public static void main(String[] args) {
SpringApplication.run(ProtobufApplication.class, args);
}
}
③ bootstrap.yml
yml
server:
port: 10001
2.4 编译生成 UserProtos.java
在上面代码准备就绪后执行 执行 mvn compile
命令 , 就可以生成 UserProtos.java,
我这里生成的UserProtos.java, 有2912行, 就不放代码了
2.5 测试 UserProtos.java
UserProtosSamples.java
java
package cn.protobuf.demo;
import cn.protobuf.proto.UserProtos;
import com.google.protobuf.util.JsonFormat;
public final class UserProtosSamples {
public static void main(String[] args) throws Exception {
UserProtos.User user = buildSampleUser(); // ① 构造
byte[] bytes = serialize(user); // ② 序列化
UserProtos.User parsed = deserialize(bytes); // ③ 反序列化
printUser(parsed); // ④ 打印内容
String json = toJson(parsed); // ⑤ protobuf → JSON UserProtos.User fromJson = fromJson(json); // ⑥ JSON → protobuf printUser(fromJson); // ⑦ 再打印一次
}
// ① 构造示例 User public static UserProtos.User buildSampleUser() {
return UserProtos.User.newBuilder()
.setId(1L)
.setName("Tom")
.setEmail("tom@example.com")
.setAge(18)
.addAddresses(UserProtos.Address.newBuilder()
.setStreet("中关村大街")
.setCity("北京")
.setZip("100080")
.build())
.addScores(90L)
.addScores(95L)
.putExt("vip", "true")
.build();
}
// ② 序列化:User → byte[]
public static byte[] serialize(UserProtos.User user) {
return user.toByteArray();
}
// ③ 反序列化:byte[] → User
public static UserProtos.User deserialize(byte[] bytes) throws Exception {
return UserProtos.User.parseFrom(bytes);
}
// ④ 打印 User 的字段、地址列表、扩展 map public static void printUser(UserProtos.User user) {
System.out.println("----- User -----");
System.out.printf("id=%d, name=%s, email=%s, age=%d%n",
user.getId(), user.getName(), user.getEmail(), user.getAge());
for (UserProtos.Address addr : user.getAddressesList()) {
System.out.printf(" address: %s, %s, %s%n",
addr.getStreet(), addr.getCity(), addr.getZip());
}
user.getExtMap().forEach((k, v) ->
System.out.printf(" ext[%s]=%s%n", k, v));
}
// ⑤ protobuf → JSON public static String toJson(UserProtos.User user) throws Exception {
return JsonFormat.printer().print(user);
}
// ⑥ JSON → protobuf public static UserProtos.User fromJson(String json) throws Exception {
UserProtos.User.Builder builder = UserProtos.User.newBuilder();
JsonFormat.parser().merge(json, builder);
return builder.build();
}
private UserProtosSamples() {} // 防止实例化
}
执行后输出:
sql
----- User -----
id=1, name=Tom, email=tom@example.com, age=18
address: 中关村大街, 北京, 100080
ext[vip]=true
----- User -----
id=1, name=Tom, email=tom@example.com, age=18
address: 中关村大街, 北京, 100080
ext[vip]=true
Process finished with exit code 0