maven install 出錯解決

No goals have been specified for this build

今天通過
mvn archetype:create -DgroupId=ricki.cheung.struts
-DartifactId=my_struts -DarchetypeGroupId=org.apache.struts
-DarchetypeArtifactId=struts2-archetype-blank
-DarchetypeVersion=2.0.14-SNAPSHOT
-DremoteRepositories=http://people.apache.org/repo/m2-snapshot-repository
命令又構建了一個Struts2工程並匯入eclipse，按右鍵pom.xml檔案，選擇【Run As】-【Maven build】的時候，報：
[INFO] Scanning for projects…[INFO]
[INFO] BUILD FAILURE[INFO]
[INFO] Total time: 0.109s[INFO] Finished at: Wed Apr 13 11:04:20 CST 2011[INFO] Final Memory: 1M/4M[INFO]
ERROR] No goals have been specified for this build. You must specify a valid lifecycle phase or a goal in the format <plugin-prefix>:<goal> or <plugin-group-id>:<plugin-artifact-id>[:<plugin-version>]:<goal>. Available lifecycle phases are: validate, initialize, generate-sources, process-sources, generate-resources,
process-resources, compile, process-classes, generate-test-sources, process-test-sources, generate-test-resources, process-test-resources, test-compile, process-
test-classes, test, prepare-package, package, pre-integration-test, integration-test, post-integration-test, verify, install, deploy, pre-site, site, post-site, site-deploy,
pre-clean, clean, post-clean. -> [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/confluence/display/MAVEN/NoGoalSpecifiedException 

eclipse安裝的maven外掛程式是m2eclipse，在控制台使用命令mvn compile並未報錯。後在pom.xml檔案<build>標籤後面加 上<defaultGoal>compile</defaultGoal>即可。

其實使用命令列時就已經指定了phase，而使用m2eclipse的【Run As】-【Maven build】時並未為其指定goal或phase，所以才報這個錯誤。