<packaging>war</packaging>

  <dependencyManagement>
 <dependencies>
  <dependency>
  <!-- Import dependency management from Spring Boot -->
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-dependencies</artifactId>
  <version>1.5.6.RELEASE</version>
  <type>pom</type>
  <scope>import</scope>
  </dependency>
 </dependencies>
 </dependencyManagement>

    <dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-web</artifactId>
  <exclusions>
  <exclusion>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-tomcat</artifactId>
  </exclusion>
  </exclusions>
 </dependency>

  <build>
 <plugins>
  <plugin>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-maven-plugin</artifactId>
  </plugin>
 </plugins>
 </build>

/**
 * WAR application
 */
@SpringBootApplication
public class WarApplication extends SpringBootServletInitializer {
 
 public static void main(String[] args) {
 SpringApplication.run(WarApplication.class, args);
 }
}

$mvn clean package

  /**
 * Configure the application. Normally all you would need to do is to add sources
 * (e.g. config classes) because other settings have sensible defaults. You might
 * choose (for instance) to add default command line arguments, or set an active
 * Spring profile.
 * @param builder a builder for the application context
 * @return the application builder
 * @see SpringApplicationBuilder
 */
 protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
 return builder;
 }