我在netbeans 8.2上工作，所以当我在maven -javafx上创建一个项目时，该项目无法构建，它会给出以下错误。

Failed to execute goal org.apache.maven.plugins:maven-archetype-
plugin:3.0.1:generate (default-cli) on project standalone-pom: 
Execution default-cli of goal org.apache.maven.plugins:maven-archetype-plugin:3.0.1:generate failed:
Plugin org.apache.maven.plugins:maven-archetype-plugin:3.0.1 
or one of its dependencies could not be resolved: 
The following artifacts could not be resolved: org.codehaus.groovy:groovy:jar:1.8.3, 
org.apache.ant:ant:jar:1.8.1: 
Could not transfer artifact org.codehaus.groovy:groovy:jar:1.8.3 from/to central 
(http://repo.maven.apache.org/maven2): repo.maven.apache.org: Unknown host repo.maven.apache.org -> [Help 1]

要查看错误的完整堆栈跟踪，请使用-e开关重新运行Maven。使用-X开关重新运行Maven以启用完整的调试日志记录。

还附上了一张图片，请帮助我解决这个问题。问题的图片