protobuf－java入门指南
2017-05-03 本文已影响0人
liujianhuiouc
简介
protobuf是google提出的一种于语言无关的序列化协议，经常用于RPC之间的通信协议，其具有简单、编解码高效、空间占用率低等特点深受广大用户的喜好，其已经广泛应用于诸多的开源软件中，详情请参考protobuff。
protobuf性能对比图
序列化大小
序列化耗时
具体的数字
安装步骤
window环境
- 下载protobuf，解压。
- 下载protobuf-2.5.0-windows.zip。
- 解压protobuf-2.5.0-windows.zip，把protoc.exe放在Protobuf安装目录下的src里。（其实放哪都可以）
- 将protoc.exe的位置信息加入到PATH变量中
配置PATH
mac环境
- 通过brew进行安装，brew install protobuf250
-
protoc --version验证是否安装成功
环境验证
创建maven工程
- pom文件如下所示，添加对protobuf的依赖，同时在build中添加hadoop-maven-plugins保证在generate-sources的时候生成java源代码。
<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>com.aliyun.sts.sample</groupId>
<artifactId>sts-sdk-sample</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<name>sts-sdk-sample</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<actVer>5.22.0</actVer>
<protobuf.version>2.5.0</protobuf.version>
<protoc.path>${env.HADOOP_PROTOC_PATH}</protoc.path>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.google.protobuf</groupId>
<artifactId>protobuf-java</artifactId>
<version>2.5.0</version>
</dependency>
</dependencies>
<build>
<plugins>
<!-- Maven Assembly Plugin -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>2.4.1</version>
<configuration>
<!-- get all project dependencies -->
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
<!-- MainClass in mainfest make a executable jar -->
<archive>
<manifest>
<mainClass>com.aliyun.sts.sample.OnboardingRequest</mainClass>
</manifest>
</archive>
</configuration>
<executions>
<execution>
<id>make-assembly</id>
<!-- bind to the packaging phase -->
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-maven-plugins</artifactId>
<executions>
<execution>
<id>compile-protoc</id>
<phase>generate-sources</phase>
<goals>
<goal>protoc</goal>
</goals>
<configuration>
<protocVersion>${protobuf.version}</protocVersion>
<protocCommand>${protoc.path}</protocCommand>
<imports>
<param>${basedir}/src/main/java/com/aliyun/sts/sample/proto</param>
</imports>
<source>
<directory>${basedir}/src/main/java/com/aliyun/sts/sample/proto</directory>
<includes>
<include>mobile.proto</include>
</includes>
</source>
<output>${project.build.directory}/generated-sources/java</output>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
-
maven工程组织结构参考下图
工程结构图
-
构建mobile.proto文件，定义消息类的格式信息。
option java_package = "com.aliyun.sts.sample.proto";
option java_outer_classname = "Mobile";
option java_generate_equals_and_hash = true;
package com.liujianhui;
message MobilePhone{
required string brand = 1 ;
required Hardware hardware = 2;
repeated string software = 3;
}
message Hardware {
required int32 rom = 1;
required int32 ram = 2;
required int32 size = 3 ;
}
4.测试类，完成序列化和反序列化操作
package com.aliyun.sts.sample.proto;
import com.google.protobuf.InvalidProtocolBufferException;
/**
* Created by liujianhui on 17/5/3.
*/
public class MobieTest {
public static void main(String[] args) throws InvalidProtocolBufferException {
Mobile.MobilePhone.Builder builder = Mobile.MobilePhone.newBuilder();
Mobile.Hardware.Builder hardware = Mobile.Hardware.newBuilder();
hardware.setRam(2).setRom(16).setSize(5);
builder.setHardware(hardware)
.setBrand("Apple")
.addSoftware("camera")
.addSoftware("tecent")
.addSoftware("browser")
.addSoftware("player");
byte[] messageBody = builder.build().toByteArray();
int headerLen = 1;
byte[] message = new byte[headerLen+messageBody.length];
message[0] = (byte)messageBody.length;
System.arraycopy(messageBody, 0, message, 1, messageBody.length);
System.out.println("msg len:"+message.length);
Mobile.MobilePhone phone = Mobile.MobilePhone.parseFrom(messageBody);
System.out.println("Receive:");
System.out.println(phone.toString());
}
}
5.测试结果，首先直接maven clean compile生成相关代码，然后运行MobileTest
msg len:49
Receive:
brand: "Apple"
hardware {
rom: 16
ram: 2
size: 5
}
software: "camera"
software: "tecent"
software: "browser"
software: "player"
6.生成的源代码结构如下图所示
生成的源文件
