protobuf-maven-plugin 配置

`protobuf-maven-plugin` 是一个 Maven 插件，用于将 Protocol Buffers 文件编译成 Java 代码。以下是一个 `protobuf-maven-plugin` 的配置示例：

<build>
  <plugins>
    <plugin>
      <groupId>org.xolstice.maven.plugins</groupId>
      <artifactId>protobuf-maven-plugin</artifactId>
      <version>0.6.1</version>
      <executions>
        <execution>
          <goals>
            <goal>compile</goal>
            <goal>compile-custom</goal>
            <goal>test-compile</goal>
            <goal>test-compile-custom</goal>
          </goals>
        </execution>
      </executions>
      <configuration>
        <protocExecutable>/usr/local/bin/protoc</protocExecutable>
        <inputDirectories>
          <include>src/main/protobuf</include>
        </inputDirectories>
        <outputDirectory>${project.build.directory}/generated-sources</outputDirectory>
        <clearOutputDirectory>true</clearOutputDirectory>
        <includeDirectories>
          <include>/usr/local/include</include>
        </includeDirectories>
        <protoSourceRoot>src/main/protobuf</protoSourceRoot>
        <pluginId>protobuf-maven-plugin</pluginId>
        <pluginArtifactId>protobuf-maven-plugin</pluginArtifactId>
        <pluginVersion>0.6.1</pluginVersion>
        <parameters>
          <param>disable_service_generator=true</param>
        </parameters>
      </configuration>
    </plugin>
  </plugins>
</build>

此配置将在 Maven 构建过程中使用 `protobuf-maven-plugin` 编译 `src/main/protobuf` 目录下的 Protocol Buffers 文件，并将生成的 Java 代码放置在 `${project.build.directory}/generated-sources` 目录下。其中，`<protocExecutable>` 指定了 `protoc` 编译器的路径，`<includeDirectories>` 指定了编译器需要的头文件目录，`<parameters>` 可以指定其他编译器参数。