1、五大核心
groupId:artifactId:packaging:classifier:version.
2、三核心
groupId:artifactId:version are all required fields. The three fields act much like an address and timestamp in one. This marks a specific place in a repository, acting like a coordinate system for Maven projects.
3、版本关系
One powerful aspect of Maven is in its handling of project relationships; that includes dependencies (and transitive dependencies), inheritance, and aggregation (multi-module projects)
原文：http://www.cnblogs.com/shunliu-java/p/4691376.html