参考文档：

第1步骤：设置父项目中maven的pom.xml内容

pom.xml文件的基础内容应该包含如下：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.clouddemo</groupId>
    <artifactId>clouddemo</artifactId>
    <packaging>pom</packaging>
    <version>1.0-SNAPSHOT</version>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <spring-cloud.version>Finchley.SR2</spring-cloud.version>
        <spring-cloud-alibaba.version>0.2.1.RELEASE</spring-cloud-alibaba.version>
        <druid-starter.version>1.1.10</druid-starter.version>
        <swagger2.version>2.9.2</swagger2.version>
        <lombok.version>1.16.20</lombok.version>
        <mybatis-plus.version>2.2.0</mybatis-plus.version>
        <tk.mybatis.starter.version>2.0.4</tk.mybatis.starter.version>
        <!--升级SpringBoot2.0.x后出现Which fixed NoSuchMethodError.RedisConnection.set([B[B)V issue
        ，需要解决https://github.com/spring-projects/spring-security-oauth2-boot/issues/27，
        SpringBoot2.1.X已经解决，真是坑啊，所以说不要盲目的升级！！！-->
        <spring-security-oauth.version>2.3.3.RELEASE</spring-security-oauth.version>
        <com.spotify-version>0.4.13</com.spotify-version>
    </properties>
    <!--默认从 Spring Boot继承-->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.8.RELEASE</version>
    </parent>
    <!--指定子模块-->
    <modules>
        <module>oauth2</module>
    </modules>
    <dependencies>

    </dependencies>
    <dependencyManagement>
        <dependencies>

        </dependencies>
    </dependencyManagement>
    <build>
        <plugins>

        </plugins>
    </build>
    <repositories>
        <repository>
            <id>alimaven</id>
            <name>aliyun maven</name>
            <url>http://maven.aliyun.com/nexus/content/groups/public/</url>
        </repository>
    </repositories>
</project>

第2步骤：子项目oauth2中添加springboot启动类

在oauth2项目中添加maven依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>clouddemo</artifactId>
        <groupId>com.clouddemo</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <!--默认从 Spring Boot继承-->
    <modelVersion>4.0.0</modelVersion>
    <artifactId>oauth2</artifactId>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>
</project>

代码如下：

package com.clouddemo.oauth2;
@Controller
@SpringBootApplication
public class AuthCenterApplication {
    @RequestMapping(value ="/home", method = RequestMethod.GET)
    @ResponseBody
    public String home(){
        return "你好，Spring Boot";
    }

    public static void main(String[] args){
        SpringApplication.run(AuthCenterApplication.class, args);
    }
}

这时候会提示我们找不到springboot的依赖类，如下图