项目小的话每次重新部署服务还能接受，但是项目体量大起来之后每次都要重新部署简直太折磨了，也造成了不必要的资源浪费；ok，那我们使用热部署之后，它会监督spring项目修改点，把修改点的java文件编译成class文件，然后替换掉修改前的class文件，不用再去重新部署了。（另外给大家以及我自己提醒，热部署在开发环境用即可，禁止在生产环境使用，不然能把你坑死）
配置步骤1、首先给我们的项目导入devtools依赖，可以在maven中央仓库 https://mvnrepository.com 搜索devtools，然后选择版本。
添加到我们的项目，Reload一下
2、打开idea左上角File->Settings->搜索Compiler，勾上红框里的选择，Apply
启动问题我们配置完成之后可能会出现以下报错：
java.lang.IllegalArgumentException: Unresolvable class definition for class [org.springframework.boot.devtools.autoconfigure.DevToolsDataSourceAutoConfiguration$DatabaseShutdownExecutorEntityManagerFactoryDependsOnPostProcessor] at org.springframework.util.ClassUtils.resolveClassName(ClassUtils.java:324) ~[spring-core-5.2.2.RELEASE.jar:5.2.2.RELEASE] at org.springframework.core.annotation.TypeMappedAnnotation.adapt(TypeMappedAnnotation.java:483) ~[spring-core-5.2.2.RELEASE.jar:5.2.2.RELEASE] at org.springframework.core.annotation.TypeMappedAnnotation.getValue(TypeMappedAnnotation.java:403) ~[spring-core-5.2.2.RELEASE.jar:5.2.2.RELEASE] at org.springframework.core.annotation.TypeMappedAnnotation.asMap(TypeMappedAnnotation.java:288) ~[spring-core-5.2.2.RELEASE.jar:5.2.2.RELEASE] at org.springframework.core.annotation.AbstractMergedAnnotation.asAnnotationAttributes(AbstractMergedAnnotation.java:193) ~[spring-core-5.2.2.RELEASE.jar:5.2.2.RELEASE] at org.springframework.core.type.AnnotatedTypeMetadata.getAnnotationAttributes(AnnotatedTypeMetadata.java:106) ~[spring-core-5.2.2.RELEASE.jar:5.2.2.RELEASE] at org.springframework.context.annotation.AnnotationConfigUtils.attributesFor(AnnotationConfigUtils.java:285) ~[spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE] at org.springframework.context.annotation.AnnotationBeanNameGenerator.determineBeanNameFromAnnotation(AnnotationBeanNameGenerator.java:100) ~[spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE] at org.springframework.context.annotation.AnnotationBeanNameGenerator.generateBeanName(AnnotationBeanNameGenerator.java:79) ~[spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE] at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.registerBeanDefinitionForImportedConfigurationClass(ConfigurationClassBeanDefinitionReader.java:160) ~[spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE] at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForConfigurationClass(ConfigurationClassBeanDefinitionReader.java:141) ~[spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE] at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitions(ConfigurationClassBeanDefinitionReader.java:120) ~[spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE] at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:337) ~[spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE] at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:242) ~[spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE] at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:275) ~[spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE] at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:95) ~[spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE] at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:706) ~[spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE] at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:532) ~[spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE] at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE] at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) [spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE] at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) [spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) [spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) [spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) [spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE] at com.cl.springcloud.PaymentMain8001.main(PaymentMain8001.java:10) [classes/:na] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_311] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_311] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_311] at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_311] at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-2.6.7.jar:2.6.7] Caused by: java.lang.NoClassDefFoundError: org/springframework/boot/autoconfigure/orm/jpa/EntityManagerFactoryDependsOnPostProcessor at java.lang.ClassLoader.defineClass1(Native Method) ~[na:1.8.0_311] at java.lang.ClassLoader.defineClass(ClassLoader.java:756) ~[na:1.8.0_311] at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) ~[na:1.8.0_311] at java.net.URLClassLoader.defineClass(URLClassLoader.java:473) ~[na:1.8.0_311] at java.net.URLClassLoader.access$100(URLClassLoader.java:74) ~[na:1.8.0_311] at java.net.URLClassLoader$1.run(URLClassLoader.java:369) ~[na:1.8.0_311] at java.net.URLClassLoader$1.run(URLClassLoader.java:363) ~[na:1.8.0_311] at java.security.AccessController.doPrivileged(Native Method) ~[na:1.8.0_311] at java.net.URLClassLoader.findClass(URLClassLoader.java:362) ~[na:1.8.0_311] at java.lang.ClassLoader.loadClass(ClassLoader.java:418) ~[na:1.8.0_311] at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:355) ~[na:1.8.0_311] at java.lang.ClassLoader.loadClass(ClassLoader.java:351) ~[na:1.8.0_311] at java.lang.Class.forName0(Native Method) ~[na:1.8.0_311] at java.lang.Class.forName(Class.java:348) ~[na:1.8.0_311] at org.springframework.boot.devtools.restart.classloader.RestartClassLoader.loadClass(RestartClassLoader.java:145) ~[spring-boot-devtools-2.6.7.jar:2.6.7] at java.lang.ClassLoader.loadClass(ClassLoader.java:351) ~[na:1.8.0_311] at java.lang.Class.forName0(Native Method) ~[na:1.8.0_311] at java.lang.Class.forName(Class.java:348) ~[na:1.8.0_311] at org.springframework.util.ClassUtils.forName(ClassUtils.java:277) ~[spring-core-5.2.2.RELEASE.jar:5.2.2.RELEASE] at org.springframework.util.ClassUtils.resolveClassName(ClassUtils.java:317) ~[spring-core-5.2.2.RELEASE.jar:5.2.2.RELEASE] ... 29 common frames omitted Caused by: java.lang.ClassNotFoundException: org.springframework.boot.autoconfigure.orm.jpa.EntityManagerFactoryDependsOnPostProcessor at java.net.URLClassLoader.findClass(URLClassLoader.java:387) ~[na:1.8.0_311] at java.lang.ClassLoader.loadClass(ClassLoader.java:418) ~[na:1.8.0_311] at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:355) ~[na:1.8.0_311] at java.lang.ClassLoader.loadClass(ClassLoader.java:351) ~[na:1.8.0_311] ... 49 common frames omitted
这里可以看到选择的版本和springboot不一致，可能会出现问题，把版本统一就好了。
修改前：
修改后：
我这里是做了版本统一管理，方便后续迭代，在自己的版本处修改即可。
测试
