添加tomcat7支持

在POM.xml中添加<dependency>
<groupId>org.apache.tomcat</groupId>
<artifactId>tomcat-servlet-api</artifactId>
<version>7.0.30</version>
<scope>provided</scope>
</dependency>和修改plugin为
<plugin>
<groupId>org.apache.tomcat.maven</groupId>
<artifactId>tomcat7-maven-plugin</artifactId>
<version>2.0</version>
</plugin>