idea使用外置tomcat配置springboot详细步骤

 创建一个maven项目
导入springboot依赖，注意底下注释部分

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.znsd.springboot</groupId>
    <artifactId>springboot-jsp</artifactId>
    <version>1.0-SNAPSHOT</version>
    
    
    <!-- 一定要声明war包 -->
    <packaging>war</packaging>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.12.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- 去除springboot默认tomcat依赖,让其在生成war包时无效， -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <!--在编译和测试有效，生成war包时无效-->
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

完成下图操作保存即可

配置tomcat启动项

配置视图解析器

创建一个springboot主程序

@SpringBootApplication
public class SpringBootMain {
    public static void main(String[] args) {
        SpringApplication.run(SpringBootMain.class,args);
    }
}

必须编写一个SpringBootServletInitializer的子类，并调用configure方法里面的固定写法

public class ServletInitializer extends SpringBootServletInitializer {
    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        //传入SpringBoot的主程序，
        return application.sources(SpringBootMain.class);
    }
}

然后启动tomcat，控制台输出了spring就启动成功了