pom.xml中properties作用

可以在properties下声明相应的版本信息，然后在dependency下引用的时候用${spring-version}就可以引入该版本jar包了

<properties>
 
        <spring-version>4.3.7.RELEASE</spring-version>
 
    </properties>
 
 
    <!--dependencies-->
 
 
    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring-version}</version>
        </dependency>
 
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring-version}</version>
        </dependency>
 
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring-version}</version>
        </dependency>
 
    </dependencies>