maven 中maven dependencies中依赖出现了项目，无法打包 ，出现的错误如图。说明:依赖的项目为project-dao 打包的项目为project-service 都在project-parent中有依赖。
[INFO] Scanning for projects...
[INFO]
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[INFO] Building project-service 0.0.1-SNAPSHOT
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[INFO] BUILD FAILURE
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[INFO] Total time: 0.507s
[INFO] Finished at: Thu May 22 09:45:55 CST 2014
[INFO] Final Memory: 4M/15M
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[ERROR] Failed to execute goal on project project-service: Could not resolve dependencies for project com.newhero.project:project-service:jar:0.0.1-SNAPSHOT: Failed to collect dependencies for [com.newhero.project:project-dao:jar:0.0.1-SNAPSHOT (compile?)]: Failed to read artifact descriptor for com.newhero.project:project-dao:jar:0.0.1-SNAPSHOT: Could not find artifact com.newhero.project:project-parent:pom:0.0.1-SNAPSHOT -> [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/DependencyResolutionException
解决方法：需要把parent工程，也就是project-parent工程先install一下，再试一下能不能打包project-service，不行的话再看看ERROR里的描述，找到描述语句的最后一个工程，把它install，这样就能打包project-service了。