用Maven实现一个protobuf的Java例子

注：试验环境在Mac Idea环境下

1. 介绍Protocol Buffers

Protocal Buffers(简称protobuf)是谷歌的一项技术，用于结构化的数据序列化、反序列化，常用于RPC 系统（Remote Procedure Call Protocol System）和持续数据存储系统。

其类似于XML生成和解析，但protobuf的效率高于XML，不过protobuf生成的是字节码，可读性比XML差，类似的还有json、Java的Serializable等。

很适合做数据存储或 RPC 数据交换格式。可用于通讯协议、数据存储等领域的语言无关、平台无关、可扩展的序列化结构数据格式。

2. Idea 安装protobuf插件

安装插件protobuf Support，之后重启

3. 配置依赖

pom.xml添加

<dependencies>
        <dependency>
            <groupId>com.google.protobuf</groupId>
            <artifactId>protobuf-java</artifactId>
            <version>3.4.0</version>
        </dependency>
</dependencies>
<build>
        <extensions>
            <extension>
                <groupId>kr.motd.maven</groupId>
                <artifactId>os-maven-plugin</artifactId>
                <version>1.4.1.Final</version>
            </extension>
        </extensions>
        <plugins>
            <plugin>
                <groupId>org.xolstice.maven.plugins</groupId>
                <artifactId>protobuf-maven-plugin</artifactId>
                <version>0.5.0</version>
                <configuration>
                    <protocArtifact>
                        com.google.protobuf:protoc:3.1.0:exe:${os.detected.classifier}
                    </protocArtifact>
                    <pluginId>grpc-java</pluginId>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>compile</goal>
                            <goal>compile-custom</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
</build>

4. 书写proto文件

syntax = "proto3";
option java_package = "com.jihite";
option java_outer_classname = "PersonModel";

message Person {
     int32 id = 1;
     string name = 2;
     string email = 3;
}

5. 转化成Java文件

6. 测试

把生成的类考的代码路径下，用下面测试用例测试

package com.jihite;

import com.google.protobuf.InvalidProtocolBufferException;
import org.junit.Test;
public class protobufTest {
    @Test
    public void testN() throws InvalidProtocolBufferException {
        PersonModel.Person.Builder builder = PersonModel.Person.newBuilder();
        builder.setId(1);
        builder.setName("jihite");
        builder.setEmail("jihite@jihite.com");

        PersonModel.Person person = builder.build();
        System.out.println("before:" + person);

        System.out.println("===Person Byte:");
        for (byte b : person.toByteArray()) {
            System.out.print(b);
        }
        System.out.println("================");

        byte[] byteArray = person.toByteArray();
        PersonModel.Person p2 = PersonModel.Person.parseFrom(byteArray);
        System.out.println("after id:" + p2.getId());
        System.out.println("after name:" + p2.getName());
        System.out.println("after email:" + p2.getEmail());

    }
}

结果

before:id: 1
name: "jihite"
email: "jihite@jihite.com"

===Person Byte:
811861061051041051161012617106105104105116101641061051041051161014699111109================
after id:1
after name:jihite
after email:jihite@jihite.com