參考:https://www.cnblogs.com/zxguan/p/7847105.html
修改maven的配置(解壓目錄的conf\setting.xml文件)
<profile>
<id>jdk1.7</id>
<activation>
<activeByDefault>true</activeByDefault>
<jdk>1.7</jdk>
</activation>
<properties>
<maven.compiler.source>1.7</maven.compiler.source>
<maven.compiler.target>1.7</maven.compiler.target>
<maven.compiler.compilerVersion>1.7</maven.compiler.compilerVersion>
</properties>
</profile>