maven-antrun-plugin: protobuf的生成源不生成Java文件

Question

我的pom.xml中有以下插件，用于生成编译其他项目所需的java文件：

<plugin>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.2</version>
    <configuration>
        <source>${jdk.version}</source>
        <target>${jdk.version}</target>
    </configuration>
</plugin>
<plugin>
    <groupId>org.apache.felix</groupId>
    <artifactId>maven-bundle-plugin</artifactId>
    <extensions>true</extensions>
    <configuration>
        <archive>
            <manifestFile>META-INF/MANIFEST.MF</manifestFile>
        </archive>
    </configuration>
</plugin>
<plugin>
    <artifactId>maven-antrun-plugin</artifactId>
    <executions>
        <execution>
            <id>generate-sources</id>
            <phase>generate-sources</phase>
            <configuration>
                <tasks>
                    <mkdir dir="src-gen" />
                    <exec executable="protoc">
                        <arg value="--java_out=src-gen" />
                        <arg value="proto/ros/RosTime.proto" />
                        <arg value="proto/ros/RosHeader.proto" />
                        <arg value="proto/ros/RosPoint.proto" />
                        <arg value="proto/ros/RosPose.proto" />
                        <arg value="proto/ros/RosPoseStamped.proto" />
                        <arg value="proto/ros/RosQuaternion.proto" />
                        <arg value="proto/U.proto" />
                        <arg value="proto/S.proto" />
                        <arg value="proto/Z.proto" />
                        <arg value="proto/algorithm/A.proto" />
                        <arg value="proto/algorithm/B.proto" />
                        <arg value="proto/algorithm/C.proto" />
                        <arg value="proto/algorithm/D.proto" />
                        <arg value="proto/algorithm/E.proto" />
                        <arg value="proto/algorithm/F.proto" />
                        <arg value="proto/env/G.proto" />
                        <arg value="proto/env/H.proto" />
                        <arg value="proto/env/J.proto" />
                        <arg value="proto/env/K.proto" />
                        <arg value="proto/env/L.proto" />
                    </exec>
                </tasks>
                <sourceRoot>src-gen</sourceRoot>
            </configuration>
            <goals>
                <goal>run</goal>
            </goals>
        </execution>
    </executions>
</plugin>

但是，在src-gen文件夹下，这根本不会生成任何内容。然后我不断地发现错误，比如：

    cannot find symbol
[ERROR] symbol:   class AMsg
[ERROR] location: class project.messages.AFormatter

和

package project.messages.ros.RosHeader does not exist
package project.messages.ros.RosPoint does not exist
package project.messages.ros.RosPose does not exist
package project.messages.ros.RosPoseStamped does not 

基本上，它无法找到必要的文件，自然，并产生错误。我已经安装了2.5.0版本，并且正确定义了依赖项：

<dependency>
    <groupId>com.google.protobuf</groupId>
    <artifactId>protobuf-java</artifactId>
    <version>2.5.0</version>
</dependency>

我的想法用完了。到底是什么让这件事不起作用？

编辑：在mvn install -X的调试输出中引起了我的注意：

Execute:Java13CommandLauncher: Executing 'protoc' with arguments:

'--java_out=src-gen'
'proto/ros/RosTime.proto'
'proto/ros/RosHeader.proto'
'proto/ros/RosPoint.proto'
'proto/ros/RosPose.proto'
'proto/ros/RosPoseStamped.proto'
'proto/ros/RosQuaternion.proto'
 .
 .
 .
 . 
The ' characters around the executable and arguments are
not part of the command.
     [exec] ros/RosTime.proto: File not found.
     [exec] proto/ros/RosHeader.proto: Import "ros/RosTime.proto" was not found or had errors.
     [exec] proto/ros/RosHeader.proto:6:14: "project.messages.ros.RosTimeMsg" seems to be defined in "proto/ros/RosTime.proto", which is not imported by "proto/ros/RosHeader.proto".  To use it here, please add the necessary import.
  .
  .  
  .
     [INFO] --- maven-antrun-plugin:1.3:run (generate-sources) @ X.messages ---
[DEBUG] org.apache.maven.plugins:maven-antrun-plugin:jar:1.3:
[DEBUG]    org.apache.maven:maven-plugin-api:jar:2.0.4:compile
[DEBUG]    org.apache.maven:maven-project:jar:2.0.4:compile
[DEBUG]       org.apache.maven:maven-settings:jar:2.0.4:compile
[DEBUG]       org.apache.maven:maven-profile:jar:2.0.4:compile
[DEBUG]       org.apache.maven:maven-model:jar:2.0.4:compile
[DEBUG]       org.apache.maven:maven-artifact-manager:jar:2.0.4:compile
[DEBUG]          org.apache.maven:maven-repository-metadata:jar:2.0.4:compile
[DEBUG]       org.codehaus.plexus:plexus-container-default:jar:1.0-alpha-9:compile
[DEBUG]          junit:junit:jar:3.8.1:compile
[DEBUG]          classworlds:classworlds:jar:1.1-alpha-2:compile
[DEBUG]    org.apache.maven:maven-artifact:jar:2.0.4:compile
[DEBUG]    org.codehaus.plexus:plexus-utils:jar:1.5.6:compile
[DEBUG]    org.apache.ant:ant-launcher:jar:1.7.1:runtime
[DEBUG]    org.apache.ant:ant:jar:1.7.1:compile
[DEBUG] Created new class realm plugin>org.apache.maven.plugins:maven-antrun-plugin:1.3
[DEBUG] Importing foreign packages into class realm plugin>org.apache.maven.plugins:maven-antrun-plugin:1.3
[DEBUG]   Imported:  < project>runtime_shared:art.util.robot:1.0.0
[DEBUG] Populating class realm plugin>org.apache.maven.plugins:maven-antrun-plugin:1.3
[DEBUG]   Included: org.apache.maven.plugins:maven-antrun-plugin:jar:1.3
[DEBUG]   Included: junit:junit:jar:3.8.1
[DEBUG]   Included: org.codehaus.plexus:plexus-utils:jar:1.5.6
[DEBUG]   Included: org.apache.ant:ant-launcher:jar:1.7.1
[DEBUG]   Included: org.apache.ant:ant:jar:1.7.1
[DEBUG]   Excluded: org.apache.maven:maven-plugin-api:jar:2.0.4
[DEBUG]   Excluded: org.apache.maven:maven-project:jar:2.0.4
[DEBUG]   Excluded: org.apache.maven:maven-settings:jar:2.0.4
[DEBUG]   Excluded: org.apache.maven:maven-profile:jar:2.0.4
[DEBUG]   Excluded: org.apache.maven:maven-model:jar:2.0.4
[DEBUG]   Excluded: org.apache.maven:maven-artifact-manager:jar:2.0.4
[DEBUG]   Excluded: org.apache.maven:maven-repository-metadata:jar:2.0.4
[DEBUG]   Excluded: org.codehaus.plexus:plexus-container-default:jar:1.0-alpha-9
[DEBUG]   Excluded: classworlds:classworlds:jar:1.1-alpha-2
[DEBUG]   Excluded: org.apache.maven:maven-artifact:jar:2.0.4
[DEBUG] Configuring mojo org.apache.maven.plugins:maven-antrun-plugin:1.3:run from plugin realm ClassRealm[plugin>org.apache.maven.plugins:maven-antrun-plugin:1.3, parent: sun.misc.Launcher$AppClassLoader@5c647e05]
[DEBUG] Configuring mojo 'org.apache.maven.plugins:maven-antrun-plugin:1.3:run' with override configurator -->
[DEBUG]   (f) pluginArtifacts = [org.apache.maven.plugins:maven-antrun-plugin:maven-plugin:1.3:, junit:junit:jar:3.8.1:compile, org.codehaus.plexus:plexus-utils:jar:1.5.6:compile, org.apache.ant:ant-launcher:jar:1.7.1:runtime, org.apache.ant:ant:jar:1.7.1:compile]
[DEBUG]   (f) project = MavenProject: runtime_X:X.messages:1.0.0 @ /home/usr/workspace_runtime_X/X.messages/pom.xml
[DEBUG]   (f) sourceRoot = /home/usr/workspace_runtime_X/X.messages/src-gen
[DEBUG]   (f) tasks = 
[DEBUG] -- end configuration --

Answer 1

当对未创建的文件有疑问时，请确保使用绝对路径。在本例中，${basedir}允许我们获得到Maven基本目录(POM位置)的绝对路径：

<mkdir dir="${basedir}/src-gen" />
<exec executable="protoc">
    <arg value="--java_out=${basedir}/src-gen" />
    <arg value="--proto_path=${basedir}" /> <!-- proto_path needs to point to where the proto files are -->
    <arg value="proto/ros/RosTime.proto" />
    <!-- rest of proto files... -->
</exec>

然后，请注意，不推荐maven-antrun-plugin的maven-antrun-plugin参数：

不赞成。使用build maven-plugin绑定源目录。

按照建议，应该使用build-helper-maven-plugin:add-source目标将源文件夹添加到Maven项目中。配置要添加该目标的sources参数的文件夹。

尽管如此，您可能有更好的机会使用org.xolstice.maven.plugins:protobuf-maven-plugin而不是依赖于Ant任务：

Maven协议缓冲区插件使用协议缓冲区编译器(protoc)工具从指定项目的.proto (协议缓冲区定义)文件中生成Java源文件。

compile目标可以用于生成Java源文件。将您的.proto文件放在src/main/proto下(使用protoSourceRoot参数可配置)，插件将在${project.build.directory}/generated-sources/protobuf/java中生成${project.build.directory}/generated-sources/protobuf/java源文件(使用outputDirectory参数进行配置)。

如果protoc可执行文件不在PATH环境变量中，则可以使用protocExecutable参数设置它。