大致就是 工程裡分了 java 程式碼 和 scala 程式碼。

然後在java程式碼中 引用了 scala 的程式碼。 
執行不報錯。 
但是打包就是一直報錯。

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile (default-compile) on project spark-auth: Compilation failure
[ERROR] /Users/hulb/project/dipper/spark-authorizer/spark-auth/src/main/java/org/apache/spark/sql/optimizer/BaseAuthorizeImpl.java:[4,47] 找不到符號
[ERROR] 符號:   類 Authorizer
[ERROR] 位置: 程式包 org.apache.spark.sql.catalyst.optimizer
 

如果直接把java程式碼放在 scala 裡面，編譯時會直接忽略這個類，不參與編譯。

….然後搞了許久，無果。

後來在同事幫助下，在pom 里加了一個外掛，解決了報錯問題。

 <plugin>
                <groupId>net.alchim31.maven</groupId>
                <artifactId>scala-maven-plugin</artifactId>
                <version>3.3.1</version>
                <executions>
                    <execution>
                        <id>scala-compile-first</id>
                        <phase>process-resources</phase>
                        <goals>
                            <goal>add-source</goal>
                            <goal>compile</goal>
                        </goals>
                    </execution>

                    <execution>
                        <phase>compile</phase>
                        <goals>
                            <goal>compile</goal>
                            <goal>testCompile</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <scalaVersion>${scala.version}</scalaVersion>
                </configuration>
            </plugin>
 

完整pom外掛如下：

    <build>
        <plugins>

            <plugin>
                <groupId>net.alchim31.maven</groupId>
                <artifactId>scala-maven-plugin</artifactId>
                <version>3.3.1</version>
                <executions>
                    <execution>
                        <id>scala-compile-first</id>
                        <phase>process-resources</phase>
                        <goals>
                            <goal>add-source</goal>
                            <goal>compile</goal>
                        </goals>
                    </execution>

                    <execution>
                        <phase>compile</phase>
                        <goals>
                            <goal>compile</goal>
                            <goal>testCompile</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <scalaVersion>${scala.version}</scalaVersion>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.scala-tools</groupId>
                <artifactId>maven-scala-plugin</artifactId>
                <executions>
                    <execution>
                        <goals>
                            <goal>compile</goal>
                            <goal>testCompile</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <scalaVersion>${scala.version}</scalaVersion>
                    <args>
                        <arg>-target:jvm-1.8</arg>
                    </args>
                </configuration>
            </plugin>
            <!--<plugin>-->
                <!--<artifactId>maven-assembly-plugin</artifactId>-->
                <!--<configuration>-->
                    <!--<archive>-->
                    <!--</archive>-->
                    <!--<descriptorRefs>-->
                        <!--<descriptorRef>jar-with-dependencies</descriptorRef>-->
                    <!--</descriptorRefs>-->
                <!--</configuration>-->
                <!--<executions>-->
                    <!--<execution>-->
                        <!--<id>make-assembly</id>-->
                        <!--<phase>package</phase>-->
                        <!--<goals>-->
                            <!--<goal>single</goal>-->
                        <!--</goals>-->
                    <!--</execution>-->
                <!--</executions>-->
            <!--</plugin>-->
        </plugins>
    </build>