关于配置maven项目出现的问题

小街深巷

出现这样的错误是哪里没有配置好呢?求解答.
[ERROR] Failed to execute goal org.codehaus.mojo:tomcat-maven-plugin:1.1:run (default-cli) on project jeecgos: Execution default-cli of goal org.codehaus.mojo:tomcat-maven-plugin:1.1:run failed: Plugin org.codehaus.mojo:tomcat-maven-plugin:1.1 or one of its dependencies could not be resolved: The following artifacts could not be resolved: org.apache.maven:maven-plugin-api:jar:2.0.8, org.apache.maven:maven-artifact-manager:jar:2.0.8, org.apache.maven.wagon:wagon-provider-api:jar:1.0-alpha-5, org.apache.maven:maven-artifact:jar:2.0.8, org.apache.maven:maven-project:jar:2.0.8, org.apache.maven:maven-archiver:jar:2.2, org.codehaus.plexus:plexus-utils:jar:1.0.4, commons-codec:commons-codec:jar:1.3, org.apache.tomcat:catalina:jar:6.0.29, org.apache.tomcat:catalina-ha:jar:6.0.29, org.apache.tomcat:tribes:jar:6.0.29, org.apache.tomcat:el-api:jar:6.0.29, org.apache.tomcat:jasper:jar:6.0.29, org.apache.tomcat:jasper-el:jar:6.0.29, org.apache.tomcat:jasper-jdt:jar:6.0.29, org.apache.tomcat:jsp-api:jar:6.0.29, org.apache.tomcat:servlet-api:jar:6.0.29, org.apache.tomcat:coyote:jar:6.0.29, org.apache.tomcat:dbcp:jar:6.0.29: Cannot access central (https://repo.maven.apache.org/maven2) in offline mode and the artifact org.apache.maven:maven-plugin-api:jar:2.0.8 has not been downloaded from it before. -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluen ... ResolutionException