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

1. 第一种解决方案
   右击项目——>Java EE Tools——>Generate Deployment Descriptor Stub.然后系统会在src/main/webapp/WEB_INF文件加下创建web.xml文件。错误解决！
2. 第二种解决方案

<build>  <plugins>   <plugin>    <groupId>org.apache.maven.plugins</groupId>    <artifactId>maven-war-plugin</artifactId>    <version>2.6</version>    <configuration>     <failOnMissingWebXml>false</failOnMissingWebXml>    </configuration>   </plugin>  </plugins> </build>