java - 如何将 google.protobuf.Timestamp 与 protoc-jar-maven-plugin 一起使用？

Question

我一直在尝试将 protobuf 类型 google.protobuf.Timestamp 与 protoc-jar-maven-plugin 一起使用，但只收到这些编译时错误:

google/protobuf/timestamp.proto: File not found.
test.proto: Import "google/protobuf/timestamp.proto" was not found or had errors.
test.proto:9:5: "google.protobuf.Timestamp" is not defined.

原型(prototype)文件如下所示:

syntax = "proto3";

import "google/protobuf/timestamp.proto";

package test;
option java_package = "test";

message TestTimestamp {
    google.protobuf.Timestamp liveStartDate = 1;
}

pom文件有以下配置:

<build>
    <plugins>
        <plugin>
            <groupId>com.github.os72</groupId>
            <artifactId>protoc-jar-maven-plugin</artifactId>
            <version>3.6.0.1</version>
            <executions>
                <execution>
                    <id>protoc.main</id>
                    <phase>generate-sources</phase>
                    <goals>
                        <goal>run</goal>
                    </goals>
                    <configuration>
                        <protocVersion>3.6.0</protocVersion>
                        <addSources>main</addSources>
                        <includeDirectories>
                            <include>src/main/protobuf</include>
                        </includeDirectories>
                        <inputDirectories>
                            <include>src/main/protobuf</include>
                        </inputDirectories>
                    </configuration>
                </execution>
            </executions>
        </plugin>

    </plugins>
</build>

据我了解，这种类型是 proto3 的一部分，那么为什么我会收到这些错误？

Answer 1

事实证明，由于这种类型不是标准类型之一，Maven 插件需要额外的配置才能使其工作，即 <includeMavenTypes>direct</includeMavenTypes>参数，如下所示:

<build>
    <plugins>
        <plugin>
            <groupId>com.github.os72</groupId>
            <artifactId>protoc-jar-maven-plugin</artifactId>
            <version>3.6.0.1</version>
            <executions>
                <execution>
                    <id>protoc.main</id>
                    <phase>generate-sources</phase>
                    <goals>
                        <goal>run</goal>
                    </goals>
                    <configuration>
                        <protocVersion>3.6.0</protocVersion>
                        <addSources>main</addSources>
                        <includeMavenTypes>direct</includeMavenTypes>
                        <includeDirectories>
                            <include>src/main/protobuf</include>
                        </includeDirectories>
                        <inputDirectories>
                            <include>src/main/protobuf</include>
                        </inputDirectories>
                    </configuration>
                </execution>
            </executions>
        </plugin>

    </plugins>
</build>

使用此配置，可以编译 proto 文件。