SpringBoot2.x打包成war（看这篇就够了）

springboot默认打包成jar，如果想打包成war，则需要做以下三步。

1.修改pom.xml文件

　　a.将jar改成war

1 <groupId>com.test</groupId>
2 <artifactId>01-springboot-HelloWorld</artifactId>
3 <version>0.0.1-SNAPSHOT</version>
4 <packaging>war</packaging>

　　b.移除spring-boot-starter-web中嵌入式tomcat插件

 1 <!-- Add typical dependencies for a web application -->
 2 <dependency>
 3     <groupId>org.springframework.boot</groupId>
 4     <artifactId>spring-boot-starter-web</artifactId>
 5     <!-- 移除嵌入式tomcat插件 -->
 6     <exclusions>
 7         <exclusion>
 8             <groupId>org.springframework.boot</groupId>
 9             <artifactId>spring-boot-starter-tomcat</artifactId>
10         </exclusion>
11     </exclusions>
12 </dependency>

　　c.增加servlet引用

1 <dependency>
2     <groupId>javax.servlet</groupId>
3     <artifactId>javax.servlet-api</artifactId>
4     <scope>provided</scope>
5 </dependency>

2.增加启动类

 1 import org.springframework.boot.builder.SpringApplicationBuilder;
 2 import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
 3 
 4 
 5 /**
 6  * 修改启动类，继承 SpringBootServletInitializer 并重写 configure 方法
 7  */
 8 public class SpringBootStartApplication extends SpringBootServletInitializer {
 9 
10     @Override
11     protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
12          // 注意这里要指向原先用main方法执行的App启动类
13         return builder.sources(App.class);
14     }
15     
16 }