Error assembling WAR: webxml attribute is required (or pre-existing WEB-INF/web.xml if executing in update mode)

springBoot项目，报错内容：
Failed to execute goal org.apache.maven.plugins:maven-war-plugin:2.2:war (default-war) on project xxxx: Error assembling WAR: webxml attribute is required (or pre-existing WEB-INF/web.xml if executing in update mode)
方法一 pom文件中添加：
<properties> <failOnMissingWebXml>false</failOnMissingWebXml> </properties>
方法二 pom文件中添加：
<build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-war-plugin</artifactId> <version>3.0.0</version> </plugin> </plugins> </build>
方法三：
手动创建 web.xml