问题：主要是在本地仓库未找到jar包

Project build error: Non-resolvable parent POM: Failure to transfer org.springframework.boot:spring-boot-starter-parent:pom:2.2.6.RELEASE from http://repo1.maven.org/maven2 was cached in the 
 local repository, resolution will not be reattempted until the update interval of central has elapsed or updates are forced. Original error: Could not transfer artifact org.springframework.boot:spring-
 boot-starter-parent:pom:2.2.6.RELEASE from/to central (http://repo1.maven.org/maven2): Failed to transfer http://repo1.maven.org/maven2/org/springframework/boot/spring-boot-starter-parent/
 2.2.6.RELEASE/spring-boot-starter-parent-2.2.6.RELEASE.pom. Error code 501, HTTPS Required and 'parent.relativePath' points at no local POM

解决方案：

在maven的配置文件文件库

在conf文件夹下找到setting.xml文件，在文件的<mirrors>标签下添加以下库：

        <!-- 阿里云库 -->
	 <mirror>     
		<id>alimaven</id>      
		<name>aliyun maven</name>      
		<url>http://maven.aliyun.com/nexus/content/groups/public/</url>      
		<mirrorOf>central</mirrorOf>    
	</mirror>  
	<!--华为库 -->
	<mirror>      
		<id>alimaven</id>      
		<name>aliyun maven</name>      
		<url>http://maven.aliyun.com/nexus/content/groups/public/</url>      
		<mirrorOf>central</mirrorOf>    
	</mirror> 

在项目中找到pom.xml文件右键Run us  --> Maven clean或Maven install 下载jar