maven 3.6.3
JDK 1.8
Springboot 2.1.7
Mac环境

通过Intellij的spring initializer建spring boot，每一步都按照老师的步骤来，maven import没有问题，编译正常，但是在运行时报错
查看了下pom的设置也是正常的

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<version>2.1.7.RELEASE</version>
		<artifactId>spring-boot-starter-parent</artifactId>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.imooc</groupId>
	<artifactId>mall</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>mall</name>
	<description>Demo project for Spring Boot</description>

	<properties>
		<java.version>1.8</java.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
			<exclusions>
				<exclusion>
					<groupId>org.junit.vintage</groupId>
					<artifactId>junit-vintage-engine</artifactId>
				</exclusion>
			</exclusions>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

</project>

之后尝试了老师的第三种方法，手动创建maven project，建springboot，可以正常运行，不是很明白为什么第一种和第二种方法都无法在我的IDE里成功运行