SpringBoot多Module打包無法找到類

<build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <classifier>exec</classifier>
                </configuration>
            </plugin>
        </plugins>
    </build>

參考：
https://segmentfault.com/q/1010000011151233/a-1020000011151428