参考视频链接：SpringBoot学习整合_哔哩哔哩_bilibili

一、整合Servlet

1.SpringBoot整合Servlet方式一：通过注解扫描完成Servlet组件的注册

package com.example.demo.files;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * @author:
 * @date:2022/2/10
 * @description: SpringBoot整合Servlet方式一
 */
/**
 *
 *  SpringBoot整合Servlet方式一：通过注解扫描完成Servlet组件的注册  
 *  早期在web.xml中的servlet配置
 *  <servlet>
 *      <servelt-name>FirstServlet</servelt-name>
 *      <servlet-class>com.example.demo.files.FirstServelt</servlet-class>
 *  </servlet>
 *  <servlet-mapping>
 *      <servlet-name>FirstServlet</servlet-name>
 *      <url-pattern>/first</url-pattern>
 *  </servlet-mapping>
 * */
@WebServlet(name="FirstServlet",urlPatterns = "/first")
public class FirstServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doGet(req, resp);
    }
}

与之对应的启动类

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;

@SpringBootApplication
@ServletComponentScan //TODO 在SpringBoot启动时会扫描@WebServlet的类，并将该类实例化
public class DemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

2.SpringBoot整合Servlet方式二：通过方法完成Servlet组件的注册

package com.example.demo.files;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
/**
 * @author:
 * @date:2022/2/10
 * @description: SpringBoot整合Servlet方式二：通过方法完成Servlet组件的注册
 */
public class SecondServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("second servlet................");
    }
}

与之对应的启动类

package com.example.demo;
import com.example.demo.files.SecondServlet;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
/**
 * @author:
 * @date:2022/2/10
 * @description: SpringBoot整合Servlet方式二：通过方法完成Servlet组件的注册
 */
@SpringBootApplication
public class DemoApplication2 {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
    /**
     *@param: []
     *@return: org.springframework.boot.web.servlet.ServletRegistrationBean
     *@description: ServletRegistrationBean是注册servlet的一个对象
     */
    @Bean
    public ServletRegistrationBean getServletRegistrationBean(){
        ServletRegistrationBean bean=new ServletRegistrationBean(new SecondServlet());
        bean.addUrlMappings("/second");
        return bean;
    }
}

二、整合Filter

SpringBoot整合Filter方式一：通过注解完成Filter组件的注册

package com.example.demo.files;
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import java.io.IOException;
// TODO SpringBoot整合Filter方式
/**
*   SpringBoot整合Filter方式一：通过注解完成Filter组件的注册
 *   早期的web.xml配置Filter
 *   <filter>
 *       <filter-name>FirstFilter</filter-name>
 *       <filter-class>com.example.demo.files.FirstFilter</filter-class>
 *   </filter>
 *   <filter-mapping>
 *      <filter-name>FirstFilter</filter-name>
 *      <url-pattern>/first</url-pattern>
 *   </filter-mapping>
*
*/
//@WebFilter(filterName = "FirstFilter" ,urlPatterns = {"*.do","*.jsp"})//为一个filter配置多个url，对应String数组中的元素
@WebFilter(filterName = "FirstFilter" ,urlPatterns = "/first")
public class FirstFilter  implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }
    @Override
    public void destroy() {
    }
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("进入filter");
    }
}

与之对应的启动类

package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;
@SpringBootApplication
@ServletComponentScan
public class DemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

SpringBoot整合Filter方式二：通过方法完成Filter组件的注册

package com.example.demo.files;
import javax.servlet.*;
import java.io.IOException;
// TODO SpringBoot整合Filter方式
/**
 *   SpringBoot整合Filter方式二：通过方法完成Filter组件的注册
 */
public class SecondFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }
    @Override
    public void destroy() {
    }
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("进入filter");
    }
}

与之对应的启动类

@SpringBootApplication
public class DemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
    /**     SpringBoot整合Filter方式二：通过方法完成Filter组件的注册  */
    @Bean
    public FilterRegistrationBean getFilterRegistrationBean(){
        FilterRegistrationBean bean = new FilterRegistrationBean(new SecondFilter());
        //bean.addUrlPatterns(new String[]{"*.do","*.jsp"});
        bean.addUrlPatterns("/second");
        return bean;
    }
}

三、整合Listener

SpringBoot整合Listener方式一：通过注解完成Listener组件的注册

package com.example.demo.files;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;
/**
 * @author:
 * @date:2022/2/10
 * @description: SpringBoot整合Listener
 */

/**
 *
 *     SpringBoot整合Listener方式一：通过注解方式完成Listener的注册
 *
 *    早期web.xml中对Listener的配置
 *    <listener>
 *        <listener-class>com.example.demo.files.FirstListener</listener-class>
 *    </listener>
 *
 *
 * */
@WebListener
public class FirstListener implements ServletContextListener {
    @Override
    public void contextInitialized(ServletContextEvent sce) {
    }
    @Override
    public void contextDestroyed(ServletContextEvent sce) {
    }
}

与之对应的启动类

package com.example.demo;

import com.example.demo.files.SecondFilter;
import com.example.demo.files.SecondServlet;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletComponentScan;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;

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

SpringBoot整合Listener方式二：通过方法完成Listener组件的注册

package com.example.demo.files;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
/**
 * @author:
 * @date:2022/2/10
 * @description:
 */
public class SecondListener implements ServletContextListener {
    @Override
    public void contextInitialized(ServletContextEvent sce) {
    }
    @Override
    public void contextDestroyed(ServletContextEvent sce) {
    }
}

与之对应的启动类

@SpringBootApplication
public class DemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
    /**
     * @param:
     * @return:
     * @description: SpringBoot整合Listener方式二：通过方法完成Listener组件的注册
     */
    public ServletListenerRegistrationBean<SecondListener> getServletListenerRegistrationBean() {
        ServletListenerRegistrationBean<SecondListener> bean = new ServletListenerRegistrationBean<SecondListener>(new SecondListener());
        return bean;
    }
}

四、访问静态资源

springboot的静态资源目录必须是在classpath下的static目录

方式一：

方式二：

ServletContext根目录下

加入项目目录中没有webapp目录，就在src/main/webapp手动创建一个webapp,目录名称必须是叫webapp

再创建一个static存放静态文件

五、文件上传

源码：

package com.example.demo.Control;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
/**
 * @author:
 * @date:2022/2/10
 * @description:
 */
//@Controller +@ResponseBody
@RestController//方法上不用加@ResponseBody
public class controller {
    //@GetMapping("/hello")
    @RequestMapping(path = "/hello", method = RequestMethod.GET)
    public String method() {
        return "hello everyone";
    }
    //@GetMapping("/get")  //处理GET请求
    @PostMapping("/fileUpload") //处理POST请求
    public Map<String, Object> fileUpload(MultipartFile filename) throws IOException {
        //打印上传的文件名称
        System.out.println(filename.getOriginalFilename());
        //filename.transferTo(new File("e:/" + filename.getOriginalFilename()));
        Map<String, Object> map = new HashMap<>();
        map.put("msg", "ok");
        return map;
    }
}

六、整合jsp

spring并不推荐用jsp，但是也是支持的

controller层代码：

package com.example.demo.Control;
import com.example.demo.Entity.User;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
 * @author:
 * @date:2022/2/10
 * @description:
 */
//@Controller +@ResponseBody
@RestController//方法上不用加@ResponseBody
public class controller {
    //@GetMapping("/hello")
    @RequestMapping(path = "/hello", method = RequestMethod.GET)
    public String method() {
        return "hello everyone";
    }
    //@GetMapping("/get")  //处理GET请求
    @PostMapping("/fileUpload") //处理POST请求
    public Map<String, Object> fileUpload(MultipartFile filename) throws IOException {
        //打印上传的文件名称
        System.out.println(filename.getOriginalFilename());
        //filename.transferTo(new File("e:/" + filename.getOriginalFilename()));
        Map<String, Object> map = new HashMap<>();
        map.put("msg", "ok");
        return map;
    }


    /**
    *@param: [model]
    *@return: java.lang.String
    *@description: springboot 整合jsp
    */
    @RequestMapping("/showUser")
    public String showUser(Model model){
        List<User> list = new ArrayList<>();
        list.add(new User(1,"张三",20));
        list.add(new User(1,"冷少",30));
        list.add(new User(1,"王五",30));
        //需要一个model对象
        model.addAttribute("list", list);
        //跳转视图,跳转到userList.jsp
        return "userList";
    }
}

application.properties

userList.jsp

<%--
  Created by IntelliJ IDEA.
  User: Admin
  Date: 2022/2/10
  Time: 17:24
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%--导入jstl的核心标签库,通过C标签库配合EL表达式，把传过来的数据在页面中做出一个展示--%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>hello world Jsp</title>
</head>
<body>
<table border="1" align="center" width="50%">
    <tr>
        <th>ID</th>
        <th>Name</th>
        <th>Age</th>
    </tr>
    <c:forEach items="${list}" var="user">
        <tr>
            <td>${user.userid}</td>
            <td>${user.username}</td>
            <td>${user.userage}</td>
        </tr>
    <c:forEach>
</table>
</body>
</html>

七、整合freemarker

        <!--freemarker启动依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-freemarker</artifactId>
        </dependency>

打开HBuilder打开刚才的Eclipse工程-新建目录resources/templates，注意新建的目录名必须为templates

templates目录下存放*.ftl文件（ftl格式的文件编写和html语法类似）

回到Eclipse工程刷新一下，刚才resources目录下的操作会同步过来。

假如在templates下新加你一个userList.ftl文件里面是html代码，在contorler层最后直接 return userList; 便可实现视图的跳转

八、整合Thymeleaf

Thymeleaf - 使用方法及国际化(超详细)_江南烟雨却痴缠丶-CSDN博客_thymeleaf

thymeleaf资源加载问题（从Controller跳转）_清晨的第一抹阳光a的博客-CSDN博客

在springboot整合thymeleaf模板引擎中@Controller和@RestController不同注解的跳转页面方法 - 海龟先生吖 - 博客园

在springboot整合thymeleaf模板引擎中@Controller和@RestController不同注解的跳转页面方法_╱℡❄＆▓的博客-CSDN博客

thymeleaf表达式爆红问题 - 1456710017 - 博客园

IDEA开发springBoot 使用 thymeleaf 模板$表达式报红波浪线解决方案_H_233的博客-CSDN博客

thymeleaf从后台获取值（获取不到值的解决方法）_zhao13106920109的博客-CSDN博客_thymeleaf取不到model值

thymeleaf从后台获取值，分为两种情况
第一，后台是转发情况
第二，后台是重定向情况

引入pom依赖

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.3</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <!--JDK版本-->
        <java.version>1.8</java.version>
        <!--Thymeleaf版本3.0.2RELEASE 3.0的版本检查就没有那么严格了，对于编辑器自动生成不合法的标签也可以通过了-->
        <thymeleaf.version>3.0.2.RELEASE</thymeleaf.version>
        <!--2.0以上就可以了-->
        <thymeleaf-layout-dialect.version>2.0.4</thymeleaf-layout-dialect.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!--freemarker启动依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-freemarker</artifactId>
        </dependency>
        <!--Thymeleaf启动器-->
        <dependency>
            <!--需要配合spring-boot-starter-web依赖-->
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

在resources目录下新建templates目录，该目录是安全的，该目录下的内容是不允许外界直接访问的。

如果需要访问，请在application.properties中加入

#spring.resources.static-locations=classpath:/templates/,classpath:/static/
spring.web.resources.static-locations=classpath:/templates/,classpath:/static/

1 Thymeleaf的基本使用

Thymeleaf是通过特定的语法对html的标记做渲染

controller.java

    @RequestMapping("/show")
    public String showInfo(Model model) {
        model.addAttribute("msg","Thymeleaf第一个案例");
        return "thymeleaf";
    }

thymeleaf.html

<!DOCTYPE html>
<!--suppress ALL-->
<html lang="en" xmlns="http://www.w3.org/1999/xhtml"
      xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>Thymeleaf</title>
</head>
<body>
<h3></h3>
<hr/>
<p>如果你在html中书写thymeleaf表达式，表达式飘红，那么可以在html开头加上suppress ALL</p>
<p></p>
<hr/>
<p>th:text是Thymeleaf的一个标签，它可以向页面中输出一个信息，初次使用thymeleaf标签可以用快捷键导入xmlns:th=""</p>
<span th:text="Hello"></span>
<hr/>
<p>使用thymeleaf的类似于一个el表达式的语法去取数据，传入下面的span标签</p>
<span th:text="${msg}">我将来会被Thymeleaf语法动态的替换掉</span>
</body>
</html>

<html lang="en" xmlns="http://www.w3.org/1999/xhtml" xmlns:th="http://www.thymeleaf.org">
这个是我Alt+Enter导入的，老师讲的过程中没有导入这句语句。

运行结果

假如在控制台报错

解决方法一：

meta标签是编辑器自动生成的，没有结束标记，自己手动敲上一个即可。

clean一下编辑器，重启程序。

解决方法二：

pom引用

为什么成这样了呢？
控制台也没报错，返回页面就一个字符串。
答：不要让controller.java中出现@ResponseBody，否则无法跳转，会导致直接把字符串返回到页面上

Thymeleaf中th:text=“${msg}“属性标签报错无法解析变量_靠奶茶续命-CSDN博客

2 Thymeleaf字符串操作

3 日期转换操作

4 条件判断

5 迭代遍历

6 获取作用域对象中的数据

7 URL表达式

九、SpringBoot热部署

方法一-pom.xml中引入SpringLoader

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.3</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <!--<packaging>war</packaging>-->
    <name>demo</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <!--JDK版本-->
        <java.version>1.8</java.version>
        <!--Thymeleaf版本3.0.2RELEASE 3.0的版本检查就没有那么严格了，对于编辑器自动生成不合法的标签也可以通过了-->
        <thymeleaf.version>3.0.2.RELEASE</thymeleaf.version>
        <!--2.0以上就可以了-->
        <thymeleaf-layout-dialect.version>2.0.4</thymeleaf-layout-dialect.version>
    </properties>

    <profiles>
        <!--开发环境-设置为默认-->
        <profile>
            <id>dev</id>
            <activation>
                <activeByDefault>true</activeByDefault>
            </activation>
            <properties>
                <environment>dev</environment>
            </properties>
        </profile>
        <!--生产环境-关闭-->
        <profile>
            <id>prod</id>
            <activation>
                <activeByDefault>false</activeByDefault>
            </activation>
            <properties>
                <environment>prod</environment>
            </properties>
        </profile>
    </profiles>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!--Thymeleaf启动器-->
        <dependency>
            <!--需要配合spring-boot-starter-web依赖-->
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
            <!--剔除和现有依赖有冲突的包-->
            <exclusions>
                <exclusion>
                    <groupId>org.thymeleaf</groupId>
                    <artifactId>thymeleaf-spring5</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
    </dependencies>

    <build>
        <resources>
            <!--排除配置文件-->
            <resource>
                <directory>src/main/resources</directory>
                <!--先排除所有配置文件-->
                <excludes>
                    <exclude>application*.yml</exclude>
                </excludes>
            </resource>
            <!--根据激活条件引入包所需的配置和文件-->
            <resource>
                <directory>src/main/resources</directory>
                <!--引入所需环境的配置文件-->
                <filtering>true</filtering>
                <includes>
                    <include>application.yml</include>
                    <!--根据maven选择环境导入配置文件,取前面environment标签中的字段-->
                    <include>application-${environment}.yml</include>
                </includes>
            </resource>
        </resources>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>

        </plugins>
    </build>
    <!--springloader插件（springboot热部署）-->
    <build>
        <plugins>
            <plugin>
                <groupID>org.springframework.boot</groupID>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <dependencies>
                    <dependency>
                        <groupId>org.springframework</groupId>
                        <artifactId>springloaded</artifactId>
                        <version>1.2.5.RELEASE</version>
                    </dependency>
                </dependencies>
            </plugin>
        </plugins>
    </build>
</project>

缺点：java代码做部署处理，面对页面无能为力，对于修改.html页面文件不会自动热部署

注意：这种方式的缺点是springloader热部署程序是在系统后台以进程形式运行，当项目停以后，进程需要手动关闭

方法二-springboot项目中使用jar包形式去运行

下载springloaded-1.2.5RELEASE.jar放到项目中新建的lib目录下

右键项目-Run Configuration-arguments-VM arguments-配置上参数：

-javaagent:.\lib\springloaded-1.2.5RELEASE.jar -noverify

这样插件的启动和关闭相对于第一种方法比较容器一些，并且没有端口抢占现象。

方法三-springboot热部署通过dev-tools

springloader是热部署方式：对于修改.html页面文件不会自动热部署

devtools是采用重新部署方式：
具体表现之一就是我在controller层稍微修改一处地方，控制台的打印信息就重新开始打印一遍项目的启动信息

pom文件引入dev-tools依赖即可

        <!--dev-tools依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <!--有其他项目继承的时候，当前的依赖不向下传递的-->
            <optional>true</optional>
        </dependency>

原文链接：https://blog.csdn.net/qq_44885775/article/details/122853878