SpringBoot打包war部署到tomcat

项目结构：

pom.xml：

<!--① 指定打包成war-->
<packaging>war</packaging>

<dependencies>
    <!-- starter-web：spring-webmvc + autoconfigure + logback + yaml + tomcat -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
        <!-- ② 移除嵌入式tomcat插件 -->
        <exclusions>
            <exclusion>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-tomcat</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>3.1.0</version>
        <scope>provided</scope>
    </dependency>
</dependencies>

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-dependencies</artifactId>
            <!-- <version>2.1.6.RELEASE</version> -->
            <version>2.3.3.RELEASE</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <version>2.3.3.RELEASE</version>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>2.5</version>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
                <encoding>UTF-8</encoding>
            </configuration>
        </plugin>
        <plugin>
            <artifactId>maven-war-plugin</artifactId>
            <version>2.6</version>
            <configuration>
                <!-- ③ 如果想在没有web.xml文件的情况下构建WAR，请设置为false。-->
                <failOnMissingWebXml>false</failOnMissingWebXml>
            </configuration>
        </plugin>
    </plugins>
</build>

打包成war后，放到tomcat安装目录的webapps文件夹，重启tomcat，访问http://localhost:8080/helloworld/index.html，页面404，表示静态资源找不到。

重写应用启动类的configure方法后就可以了。

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

    // 不重写打包war部署到tomcat接口会报404
    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(MainClass.class);
    }
}