Olá,
Tentei realizar o comando de gerar projeto da seguinte maneira:
mvn archetype:generate -DartifactId=produtos -DgroupId=br.com.alura.maven -DinteractiveMode=false -DarchetypeArtifactId=maven-archetype-quickstart
As variáveis de ambiente JAVA_HOME e PATH estão com os caminhos necessários, mas recebo diversos erros na hora de realizar o download (Já tentei com a versão mais atual do Maven, a 3.5.4, e com a versão usada na aula, 3.3.9, mas ambas apresentam as mesmas mensagens):
[INFO] Scanning for projects...
Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-clean-plugin/2.5/maven-clean-plugin-2.5.pom
[WARNING] Failed to retrieve plugin descriptor for org.apache.maven.plugins:maven-clean-plugin:2.5: Plugin org.apache.maven.plugins:maven-clean-plugin:2.5 or one of its
dependencies could not be resolved: Failed to read artifact descriptor for org.apache.maven.plugins:maven-clean-plugin:jar:2.5
Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-install-plugin/2.4/maven-install-plugin-2.4.pom
[WARNING] Failed to retrieve plugin descriptor for org.apache.maven.plugins:maven-install-plugin:2.4: Plugin org.apache.maven.plugins:maven-install-plugin:2.4 or one of
its dependencies could not be resolved: Failed to read artifact descriptor for org.apache.maven.plugins:maven-install-plugin:jar:2.4
Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-deploy-plugin/2.7/maven-deploy-plugin-2.7.pom
[WARNING] Failed to retrieve plugin descriptor for org.apache.maven.plugins:maven-deploy-plugin:2.7: Plugin org.apache.maven.plugins:maven-deploy-plugin:2.7 or one of i
ts dependencies could not be resolved: Failed to read artifact descriptor for org.apache.maven.plugins:maven-deploy-plugin:jar:2.7
Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-site-plugin/3.3/maven-site-plugin-3.3.pom
[WARNING] Failed to retrieve plugin descriptor for org.apache.maven.plugins:maven-site-plugin:3.3: Plugin org.apache.maven.plugins:maven-site-plugin:3.3 or one of its d
ependencies could not be resolved: Failed to read artifact descriptor for org.apache.maven.plugins:maven-site-plugin:jar:3.3
Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-antrun-plugin/1.3/maven-antrun-plugin-1.3.pom
[WARNING] Failed to retrieve plugin descriptor for org.apache.maven.plugins:maven-antrun-plugin:1.3: Plugin org.apache.maven.plugins:maven-antrun-plugin:1.3 or one of i
ts dependencies could not be resolved: Failed to read artifact descriptor for org.apache.maven.plugins:maven-antrun-plugin:jar:1.3
Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-assembly-plugin/2.2-beta-5/maven-assembly-plugin-2.2-beta-5.pom
[WARNING] Failed to retrieve plugin descriptor for org.apache.maven.plugins:maven-assembly-plugin:2.2-beta-5: Plugin org.apache.maven.plugins:maven-assembly-plugin:2.2-
beta-5 or one of its dependencies could not be resolved: Failed to read artifact descriptor for org.apache.maven.plugins:maven-assembly-plugin:jar:2.2-beta-5
Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-dependency-plugin/2.8/maven-dependency-plugin-2.8.pom
[WARNING] Failed to retrieve plugin descriptor for org.apache.maven.plugins:maven-dependency-plugin:2.8: Plugin org.apache.maven.plugins:maven-dependency-plugin:2.8 or
one of its dependencies could not be resolved: Failed to read artifact descriptor for org.apache.maven.plugins:maven-dependency-plugin:jar:2.8