maven 无法将 .scala文件打入jar包

问题描述:

Maven(打包Scala程序打不进class文件和依赖的解决办法)，新建一个Maven项目，开开心心地写完scala程序，在本地调试没什么问题，要打包部署在spark集群上运行的时候却出错了，说找不到主类。

java.lang.ClassNotFoundException: com.zuo.HelloWorld
        at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:348)
        at org.apache.spark.util.Utils$.classForName(Utils.scala:229)
        at org.apache.spark.deploy.SparkSubmit$.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:700)
        at org.apache.spark.deploy.SparkSubmit$.doRunMain$1(SparkSubmit.scala:187)
        at org.apache.spark.deploy.SparkSubmit$.submit(SparkSubmit.scala:212)
        at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:126)
        at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)

打开使用IDE打好的Jar包，发现里面没有一个.class文件，

原因分析:

原来是使用IDE默认的方式打包Maven项目，不会将.scala文件打不进去

解决方案:

使用插件 maven-scala-plugin来解决

pom.xml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>com.zuo</groupId>
    <artifactId>helloworld</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>


    <properties>
        <scala.version>2.12.8</scala.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.scala-lang</groupId>
            <artifactId>scala-library</artifactId>
            <version>${scala.version}</version>
            <!--<scope>provided</scope>--><!--如果要java -jar运行,需要注释掉这里-->
        </dependency>
    </dependencies>

    <build>
        <finalName>HelloWorld</finalName>
        <plugins>
            <plugin>
                <!--用这个插件来将依赖一块打进jar包-->
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-assembly-plugin</artifactId>
                <version>3.0.0</version>
                <executions>
                    <execution>
                        <id>make-assembly</id>
                        <phase>package</phase>
                        <goals>
                            <goal>single</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <archive>
                        <manifest>
                            <mainClass>com.zuo.HelloWorld</mainClass>
                        </manifest>
                    </archive>
                    <descriptorRefs>
                        <descriptorRef>jar-with-dependencies</descriptorRef>
                    </descriptorRefs>
                </configuration>
            </plugin>
            <plugin>
                <!--scala原始在sbt(类似java maven)上做开发,现可以用这个插件来在maven中进行开发-->
                <groupId>org.scala-tools</groupId>
                <artifactId>maven-scala-plugin</artifactId>
                <version>2.15.2</version>
                <executions>
                    <execution>
                        <id>scala-compile-first</id>
                        <goals>
                            <goal>compile</goal>
                        </goals>
                        <configuration>
                            <includes>
                                <include>**/*.scala</include>
                            </includes>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

结果: