步骤一: 修改pox.xml文件
1.首先将 <packaging>jar</packaging>修改为 <packaging>war</packaging>

2.在dependencies里面添加以下代码:
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.2</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>3.4</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.datatype</groupId>
<artifactId>jackson-datatype-joda</artifactId>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.module</groupId>
<artifactId>jackson-module-parameter-names</artifactId>
</dependency>
步骤二:修改SpringBoot中的启动文件

步骤三: 操作步骤应该是在IDEA上面中找到 Build--》Build Artifacts--》点击生成war包

备注: 打包修改完后不要运行该项目,会报错的。
因为这个是为打包而设计的方案,如果大家想要运行项目的话,一定要把spring-boot-starter-tomcat中 <scope>provided</scope>注释掉才可以运行,不然肯定会出错,这点大家一定要注意。
正确的操作步骤应该是在IDEA中找到Build--》Build Artifacts--》点击生成war包,这样利用IDEA将SpringBoot的项目打包成war文件的所有步骤就完成了。