在《在不同操作系统上自动生成Protocol Buffers的Java语言包的方法》中我们使用了protobuf-maven-plugin插件来给Proto文件生成Java语言版代码。本文我们将使用一种更简单的插件来完成这个功能。
本文实验的操作系统和代码库都和《在不同操作系统上自动生成Protocol Buffers的Java语言包的方法》一样。区别仅仅是pom.xml文件。

protoc-jar-maven-plugin

本章我们使用的是protoc-jar-maven-plugin。它相较于protobuf-maven-plugin的优点是：自动识别操作系统，不用引入os-maven-plugin来新增对${os.detected.classifier}的识别。这样我们就可以用更简单的pom.xml来完成相同的功能。

<build><plugins><plugin><groupId>com.github.os72</groupId><artifactId>protoc-jar-maven-plugin</artifactId><version>3.11.4</version><executions><execution><phase>generate-sources</phase><goals><goal>run</goal></goals><configuration><protocArtifact>com.google.protobuf:protoc:${protobuf-java.version}</protocArtifact><inputDirectories><include>src/main/proto</include></inputDirectories><outputDirectory>src/main/java/protojava</outputDirectory></configuration></execution></executions></plugin></plugins>
</build>

protocArtifact用于指定protoc生成的Java依赖的版本。
inputDirectories用于指定proto文件的位置。
outputDirectory用于指定产出的文件位置。
完整文件如下

<?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>proto-message-gen</artifactId><version>1.0-SNAPSHOT</version><properties><maven.compiler.source>21</maven.compiler.source><maven.compiler.target>21</maven.compiler.target><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><protobuf-java.version>4.26.1</protobuf-java.version></properties><dependencies><dependency><groupId>com.google.protobuf</groupId><artifactId>protobuf-java</artifactId><version>${protobuf-java.version}</version></dependency><dependency><groupId>com.google.protobuf</groupId><artifactId>protobuf-java-util</artifactId><version>${protobuf-java.version}</version></dependency></dependencies><build><plugins><plugin><groupId>com.github.os72</groupId><artifactId>protoc-jar-maven-plugin</artifactId><version>3.11.4</version><executions><execution><phase>generate-sources</phase><goals><goal>run</goal></goals><configuration><protocArtifact>com.google.protobuf:protoc:${protobuf-java.version}</protocArtifact><inputDirectories><include>src/main/proto</include></inputDirectories><outputDirectory>src/main/java/protojava</outputDirectory></configuration></execution></executions></plugin></plugins></build></project>

protobuf-maven-plugin

这个方案来源于《在不同操作系统上自动生成Protocol Buffers的Java语言包的方法》。贴在这儿供大家比较选择。

<?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>proto-message-gen</artifactId><version>1.0-SNAPSHOT</version><properties><maven.compiler.source>21</maven.compiler.source><maven.compiler.target>21</maven.compiler.target><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><protobuf-java.version>4.26.1</protobuf-java.version></properties><dependencies><dependency><groupId>com.google.protobuf</groupId><artifactId>protobuf-java</artifactId><version>${protobuf-java.version}</version></dependency><dependency><groupId>com.google.protobuf</groupId><artifactId>protobuf-java-util</artifactId><version>${protobuf-java.version}</version></dependency></dependencies><build><extensions><extension><groupId>kr.motd.maven</groupId><artifactId>os-maven-plugin</artifactId><version>1.7.1</version></extension></extensions><plugins><plugin><groupId>org.xolstice.maven.plugins</groupId><artifactId>protobuf-maven-plugin</artifactId><version>0.6.1</version><extensions>true</extensions><executions><execution><goals><goal>compile</goal><goal>test-compile</goal></goals></execution></executions><configuration><protoSourceRoot>${project.basedir}/src/main/proto</protoSourceRoot><outputDirectory>${project.basedir}/src/main/java/protojava</outputDirectory><protocArtifact>com.google.protobuf:protoc:${protobuf-java.version}:exe:${os.detected.classifier}</protocArtifact></configuration></plugin></plugins></build></project>

测试代码

见《在不同操作系统上自动生成Protocol Buffers的Java语言包的方法》

代码

https://github.com/f304646673/proto-gen.git

参考资料

• https://os72.github.io/protoc-jar-maven-plugin/run-mojo.html#inputDirectories
• https://os72.github.io/protoc-jar-maven-plugin/index.html
• https://mvnrepository.com/artifact/com.github.os72/protoc-jar-maven-plugin/3.11.4
• https://github.com/os72/protoc-jar-maven-plugin
• https://medium.com/@lucian.ritan/setup-and-run-a-grpc-project-eda408c8cef0
• https://github.com/grpc/grpc-java/blob/master/examples/pom.xml
• https://stackoverflow.com/questions/35934276/using-grpc-in-maven