springboot父子类项目，打war包不成功，打包成功后放到Tomcat中不启动

今天打包父子项目，起先包如下错误

[ERROR] Plugin org.apache.maven.plugins:maven-jar-plugin:2.4 or one of its dependencies could not be resolved: Failure to find org.apache.maven.plugins:maven-jar-plugin:jar:2.4 in http://localhost:8081/nexus/content/groups/public was cached in the local repository, resolution will not be reattempted until the update interval of nexus has elapsed or updates are forced -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/PluginResolutionException

之类的错误

解决办法：在idea中，或者在cmd命令窗口，切换到项目路径下执行

1、执行 mvn clean,之后执行 mvn install

2、成功后，会在target目录下创建 所打的包.war和.war.original

3、打开cmd命令窗口，切换到war包所在路径，输入 java -jar war包，启动项目

4、发现war包在Tomcat中不能启动，Tomcat可以正常运行，不启动项目

原因：springboot项目没有启动类，

解决办法：在springboot启动类同目录下，新建如下类

import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;

/**
 * 修改启动类，继承 SpringBootServletInitializer 并重写 configure 方法
 */
public class SpringBootStartApplication extends SpringBootServletInitializer {
 
    @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(AdminApplication.class);
    }

}

*其他原因可参考https://yq.aliyun.com/articles/58273