编译hadoop2出错了,是什么原因？

[INFO] Apache Hadoop Distribution ........................ SKIPPED
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[INFO] BUILD FAILURE
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[INFO] Total time: 5:02.023s
[INFO] Finished at: Mon Jun 02 18:47:10 CST 2014
[INFO] Final Memory: 34M/121M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.codehaus.mojo:findbugs-maven-plugin:2.3.2:findbugs (default) on project hadoop-project-dist: Execution default of goal org.codehaus.mojo:findbugs-maven-plugin:2.3.2:findbugs failed: Plugin org.codehaus.mojo:findbugs-maven-plugin:2.3.2 or one of its dependencies could not be resolved: The following artifacts could not be resolved: org.codehaus.gmaven:gmaven-mojo:jar:1.3, org.codehaus.gmaven.runtime:gmaven-runtime-api:jar:1.3, org.codehaus.gmaven.feature:gmaven-feature-api:jar:1.3, org.codehaus.gmaven.runtime:gmaven-runtime-1.5:jar:1.3, org.codehaus.gmaven.feature:gmaven-feature-support:jar:1.3, org.codehaus.groovy:groovy-all-minimal:jar:1.5.8, org.apache.ant:ant:jar:1.7.1, org.apache.ant:ant-launcher:jar:1.7.1, jline:jline:jar:0.9.94, org.codehaus.gmaven:gmaven-plugin:jar:1.3, org.codehaus.gmaven.runtime:gmaven-runtime-loader:jar:1.3, org.codehaus.gmaven.runtime:gmaven-runtime-support:jar:1.3, org.sonatype.gshell:gshell-io:jar:2.0, com.thoughtworks.qdox:qdox:jar:1.10, org.apache.maven.shared:file-management:jar:1.2.1, org.apache.maven.shared:maven-shared-io:jar:1.1, org.slf4j:slf4j-api:jar:1.5.10, org.sonatype.gossip:gossip:jar:1.2, org.apache.maven.reporting:maven-reporting-impl:jar:2.1, commons-validator:commons-validator:jar:1.2.0, commons-digester:commons-digester:jar:1.6, commons-logging:commons-logging:jar:1.0.4, xml-apis:xml-apis:jar:1.0.b2, org.codehaus.groovy:groovy-all:jar:1.7.4, org.apache.maven.doxia:doxia-core:jar:1.1.3, org.apache.maven.doxia:doxia-logging-api:jar:1.1.3, org.apache.maven.doxia:doxia-sink-api:jar:1.1.3, org.apache.maven.doxia:doxia-decoration-model:jar:1.1.3, org.apache.maven.doxia:doxia-site-renderer:jar:1.1.3, org.apache.maven.doxia:doxia-module-xhtml:jar:1.1.3, org.apache.maven.doxia:doxia-module-fml:jar:1.1.3, org.apache.maven.shared:maven-doxia-tools:jar:1.2.1, com.google.code.findbugs:findbugs-ant:jar:1.3.9, com.google.code.findbugs:findbugs:jar:1.3.9, com.google.code.findbugs:jsr305:jar:1.3.9, com.google.code.findbugs:jFormatString:jar:1.3.9, com.google.code.findbugs:annotations:jar:1.3.9, dom4j:dom4j:jar:1.6.1, jaxen:jaxen:jar:1.1.1, jdom:jdom:jar:1.0, xom:xom:jar:1.0, xerces:xmlParserAPIs:jar:2.6.2, xalan:xalan:jar:2.6.0, com.ibm.icu:icu4j:jar:2.6.1, asm:asm:jar:3.1, asm:asm-analysis:jar:3.1, asm:asm-commons:jar:3.1, asm:asm-util:jar:3.1, asm:asm-tree:jar:3.1, asm:asm-xml:jar:3.1, jgoodies:plastic:jar:1.2.0, org.codehaus.plexus:plexus-resources:jar:1.0-alpha-4: Could not transfer artifact org.codehaus.gmaven:gmaven-mojo:jar:1.3 from/to central (http://repo.maven.apache.org/maven2): repo.maven.apache.org: Unknown host repo.maven.apache.org -> [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
[ERROR]
[ERROR] After correcting the problems, you can resume the build with the command
[ERROR] mvn <goals> -rf :hadoop-project-dist