<parent>

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.2.2.RELEASE</version>
    <relativePath/>
</parent>

<dependencyManagement>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-parent</artifactId>
                <version>2.2.2.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

<parent>：和Java继承一样，只能单继承，具有局限性
<dependencyManagement >：和Java组合一样，推荐使用

相同点：都能实现jar的版本管理
不同点：parent能让子工程继承自己的dependency，而dependencyManagement不行