scala开发环境备忘

1. maven管理下java中引用scala时build配置 

项目打包时，默认先编译java，再编译scala，会出现找不到scala中类的问题；可以增加以下maven插件配置，指定编译打包逻辑，但需要注意java和scala不要互相引用

    <build>
        <plugins>
            <plugin>
                <groupId>net.alchim31.maven</groupId>
                <artifactId>scala-maven-plugin</artifactId>
                <version>3.2.0</version>
                <executions>
                    <execution>
                        <id>compile-scala</id>
                        <phase>process-resources</phase>
                        <goals>
                            <goal>add-source</goal>
                            <goal>compile</goal>
                        </goals>
                    </execution>
                    <execution>
                        <id>scala-compile-first</id>
                        <phase>compile</phase>
                        <goals>
                            <goal>add-source</goal>
                            <goal>testCompile</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <scalaVersion>2.11.12</scalaVersion>
                </configuration>
            </plugin>
        </plugins>
    </build>