竟然这样操作！springcloud微服务多模块打包war部署到tomcat

父工程的pom.xml中的 <packaging>pom</packaging>
spring boot项目应用中pom.xml中的 <packaging>war<packaging>
<!--在父工程的pom.xml里，去除springboot web自带的tomcat，自己添加tomcat、servlet-api 依赖-->
    <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>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <scope>provided</scope>
    </dependency>

@SpringBootApplication
public class DemoApplication extends SpringBootServletInitializer {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication .class, args);
    }
    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
        // 注意这里要指向原先用main方法执行的Application启动类
        return builder.sources(DemoApplication .class);
    }
}