maven统一配置

<properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <spring.version>4.0</spring.version>
        <java.version>1.8</java.version>
    </properties>

在properties标签里自定义标签，引用时${java.version}