同事问了，打成war不能执行，报错，找了好久找不到原因，今天自己也碰到这个问题，一样的。

原因是servlet关联没有，二是启动时调用原始的启动类

解决方案如下：

pom.xml

1、打war

<packaging>war</packaging>

2、去掉关联，可选步骤

<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId><!-- 移除嵌入式tomcat插件 --><exclusions><exclusion><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-tomcat</artifactId></exclusion></exclusions></dependency>

3、添加servlet-api的依赖（下面任一）

<!--要放到tomcat中运行，war的方式，加这个，否则不用加--><dependency><groupId>javax.servlet</groupId><artifactId>javax.servlet-api</artifactId><version>3.1.0</version><scope>provided</scope></dependency>

<dependency><groupId>org.apache.tomcat</groupId><artifactId>tomcat-servlet-api</artifactId><version>8.0.36</version><scope>provided</scope></dependency>

4、增加启动再调用原始的main类

若原始的启动类是：AdminApplication，那么在同包中，增加如下的文件

import org.springframework.boot.builder.SpringApplicationBuilder;import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;/*** 增加这个类，修改启动类，继承 SpringBootServletInitializer 并重写 configure 方法*/public class SpringBootStartApplication extends SpringBootServletInitializer {@Overrideprotected 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);}}

或者启动类改成

import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.boot.builder.SpringApplicationBuilder;import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;@SpringBootApplicationpublic class AdminApplication extends SpringBootServletInitializer {@Overrideprotected 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);}public static void main(String[] args) {SpringApplication.run(AdminApplication.class, args);}}