SpringBoot修改代码或配置文件不生效，需要每次mvn clean mvn install

核心问题：缺少.iml文件

在idea中点击Terminal，输入mvn idea:module 生成 项目名称.iml文件，即可解决问题
如果生成失败，提示Error parsing existing IML file什么的，直接进文件夹删掉.iml文件，重新生成，再不行就关掉idea，删掉.iml文件，重新打开，生成，即可解决问题。

iml文件内容

<?xml version="1.0" encoding="UTF-8"?>
<module org.jetbrains.idea.maven.project.MavenProjectsManager.isMavenModule="true" type="JAVA_MODULE" version="4">
  <component name="FacetManager">
    <facet type="web" name="Web">
      <configuration>
        <webroots />
        <sourceRoots>
          <root url="file://$MODULE_DIR$/src/main/java" />
          <root url="file://$MODULE_DIR$/src/main/resources" />
        </sourceRoots>
      </configuration>
    </facet>
    <facet type="Spring" name="Spring">
      <configuration />
    </facet>
  </component>
  <component name="NewModuleRootManager" LANGUAGE_LEVEL="JDK_1_8">
    <output url="file://$MODULE_DIR$/target/classes" />
    <output-test url="file://$MODULE_DIR$/target/test-classes" />
    <content url="file://$MODULE_DIR$">
      <sourceFolder url="file://$MODULE_DIR$/src/main/java" isTestSource="false" />
      <sourceFolder url="file://$MODULE_DIR$/src/main/resources" type="java-resource" />
      <sourceFolder url="file://$MODULE_DIR$/src/test/java" isTestSource="true" />
      <excludeFolder url="file://$MODULE_DIR$/target" />
    </content>
    <orderEntry type="inheritedJdk" />
    <orderEntry type="sourceFolder" forTests="false" />
    <orderEntry type="library" name="Maven: org.springframework.boot:spring-boot-starter-web:2.5.3" level="project" />
    <orderEntry type="library" name="Maven: org.springframework.boot:spring-boot-starter:2.5.3" level="project" />
    <orderEntry type="library" name="Maven: org.springframework.boot:spring-boot:2.5.3" level="project" />
    <orderEntry type="library" name="Maven: org.springframework.boot:spring-boot-autoconfigure:2.5.3" level="project" />
    <orderEntry type="library" name="Maven: org.springframework.boot:spring-boot-starter-logging:2.5.3" level="project" />
    <orderEntry type="library" name="Maven: ch.qos.logback:logback-classic:1.2.4" level="project" />
    <orderEntry type="library" name="Maven: ch.qos.logback:logback-core:1.2.4" level="project" />
    <orderEntry type="library" name="Maven: org.apache.logging.log4j:log4j-to-slf4j:2.14.1" level="project" />
    <orderEntry type="library" name="Maven: org.apache.logging.log4j:log4j-api:2.14.1" level="project" />
    <orderEntry type="library" name="Maven: org.slf4j:jul-to-slf4j:1.7.32" level="project" />
    <orderEntry type="library" name="Maven: jakarta.annotation:jakarta.annotation-api:1.3.5" level="project" />
    <orderEntry type="library" name="Maven: org.yaml:snakeyaml:1.28" level="project" />
    <orderEntry type="library" name="Maven: org.springframework.boot:spring-boot-starter-json:2.5.3" level="project" />
    <orderEntry type="library" name="Maven: com.fasterxml.jackson.core:jackson-databind:2.12.4" level="project" />
    <orderEntry type="library" name="Maven: com.fasterxml.jackson.core:jackson-annotations:2.12.4" level="project" />
    <orderEntry type="library" name="Maven: com.fasterxml.jackson.core:jackson-core:2.12.4" level="project" />
    <orderEntry type="library" name="Maven: com.fasterxml.jackson.datatype:jackson-datatype-jdk8:2.12.4" level="project" />
    <orderEntry type="library" name="Maven: com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.12.4" level="project" />
    <orderEntry type="library" name="Maven: com.fasterxml.jackson.module:jackson-module-parameter-names:2.12.4" level="project" />
    <orderEntry type="library" name="Maven: org.springframework.boot:spring-boot-starter-tomcat:2.5.3" level="project" />
    <orderEntry type="library" name="Maven: org.apache.tomcat.embed:tomcat-embed-core:9.0.50" level="project" />
    <orderEntry type="library" name="Maven: org.apache.tomcat.embed:tomcat-embed-el:9.0.50" level="project" />
    <orderEntry type="library" name="Maven: org.apache.tomcat.embed:tomcat-embed-websocket:9.0.50" level="project" />
    <orderEntry type="library" name="Maven: org.springframework:spring-web:5.3.9" level="project" />
    <orderEntry type="library" name="Maven: org.springframework:spring-beans:5.3.9" level="project" />
    <orderEntry type="library" name="Maven: org.springframework:spring-webmvc:5.3.9" level="project" />
    <orderEntry type="library" name="Maven: org.springframework:spring-aop:5.3.9" level="project" />
    <orderEntry type="library" name="Maven: org.springframework:spring-context:5.3.9" level="project" />
    <orderEntry type="library" name="Maven: org.springframework:spring-expression:5.3.9" level="project" />
    <orderEntry type="library" name="Maven: org.projectlombok:lombok:1.18.20" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: org.springframework.boot:spring-boot-starter-test:2.5.3" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: org.springframework.boot:spring-boot-test:2.5.3" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: org.springframework.boot:spring-boot-test-autoconfigure:2.5.3" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: com.jayway.jsonpath:json-path:2.5.0" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: net.minidev:json-smart:2.4.7" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: net.minidev:accessors-smart:2.4.7" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: org.ow2.asm:asm:9.1" level="project" />
    <orderEntry type="library" name="Maven: org.slf4j:slf4j-api:1.7.32" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: jakarta.xml.bind:jakarta.xml.bind-api:2.3.3" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: jakarta.activation:jakarta.activation-api:1.2.2" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: org.assertj:assertj-core:3.19.0" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: org.hamcrest:hamcrest:2.2" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: org.junit.jupiter:junit-jupiter:5.7.2" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: org.junit.jupiter:junit-jupiter-api:5.7.2" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: org.apiguardian:apiguardian-api:1.1.0" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: org.opentest4j:opentest4j:1.2.0" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: org.junit.platform:junit-platform-commons:1.7.2" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: org.junit.jupiter:junit-jupiter-params:5.7.2" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: org.junit.jupiter:junit-jupiter-engine:5.7.2" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: org.junit.platform:junit-platform-engine:1.7.2" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: org.mockito:mockito-core:3.9.0" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: net.bytebuddy:byte-buddy:1.10.22" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: net.bytebuddy:byte-buddy-agent:1.10.22" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: org.objenesis:objenesis:3.2" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: org.mockito:mockito-junit-jupiter:3.9.0" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: org.skyscreamer:jsonassert:1.5.0" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: com.vaadin.external.google:android-json:0.0.20131108.vaadin1" level="project" />
    <orderEntry type="library" name="Maven: org.springframework:spring-core:5.3.9" level="project" />
    <orderEntry type="library" name="Maven: org.springframework:spring-jcl:5.3.9" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: org.springframework:spring-test:5.3.9" level="project" />
    <orderEntry type="library" scope="TEST" name="Maven: org.xmlunit:xmlunit-core:2.8.2" level="project" />
  </component>
</module>