描述
Maven3下的项目结构，target目录下会有一个m2e-wtp文件夹，删除掉会自动生成，有什么作用呢？
wtp解释
WTP：Web Tools Project
Maven集成WTP
The Maven Integration for WTP project, also known as m2e-wtp, aims at providing a tight integration between Maven Integration for Eclipse (a.k.a m2e) and the Eclipse Web Tools Project (WTP).
WTP项目的Maven集成，也称为M2e-WTP，旨在为Eclipse的Maven集成（又名M2e）和Eclipse Web工具项目（WTP）提供一个紧凑的集成。
m2e-wtp的作用
m2e-wtp provides a set of m2e connectors used for the configuration of Java EE projects in WTP, brings unique Maven features to your Eclipse IDE and helps you convert your Eclipse projects to Maven.
m2e-wtp提供一套用于在WTP java EE项目配置的m2e连接器，给你的Eclipse IDE带来独特的Maven的功能，可以帮助你把Eclipse项目转换成Maven项目。
m2e-wtp的功能
- war project configuration : adds the Java and Dynamic Web Facets
- ejb project configuration : adds the Java and EJB Facets.
- ear project configuration : adds the EAR Facet. Supports application.xml and jboss.xml file generation
- rar project configuration : adds the Java and Connector Facets.
- app-client project configuration : adds the Java and Application Client Facets.
- jar dependency project configuration : adds the Java and Utility Facets.
- web-fragment project configuration : adds the Java and Web Fragment Facets if a web-fragment.xml file is detected.
- Optional configurators for JSF, JPA and JAX-RS Facets
- war overlays of workspace dependencies and .war archives, with incremental deployment on server
- dynamic resource filtering with incremental deployment on server
- Eclipse to Maven project conversion : maps Eclipse settings to their equivalent maven plugin configuration. Available for all Java EE projects.
Maven项目project facet示例
项目右键—>Properties 
参考来源：http://www.eclipse.org/m2e-wtp/
转自：https://blog.csdn.net/fengyunhaitan/article/details/51765254