web.xml is missing and <failOnMissingWebXml> is set to true

新建maven project后可能会报错：web.xml is missing and <failOnMissingWebXml> is set to true

解决办法：

1. 右键点击Project Explorer中的Deployment Descriptor
2. 选择Generate Deployment Descriptor Stub

项目自动生成src/main/webapp/WEB-INF/web.xml文件。