Maven项目中报错?：Cannot upgrade/downgrade to Dynamic Web Module 3.0 facet. It is incompatibile with already installed facets: Java 1.6. Please modify project configuration.
解决:项目右键-->properties-->Project Facets-->Java-->修改成1.7或更高版本
Maven错误解决
原文：http://blog.51cto.com/59465168/2330871
