spring boot 和spring mvc 最大得不同是jar包和war包得区别，war包会解压，jar包不会，所以war包能找到文件，jar包不行，报错如下：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'kafkaMsgConsumer': Invocation of init method failed; nested exception is java.io.FileNotFoundException: file:\C:\thor\thor-service\thor-bus\target\classes\rr-hitube-firebase-adminsdk-ivopy-0743e9a8b3.json (文件名、目录名或卷标语法不正确。)
    at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:139) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:416) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1691) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:573) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:495) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:759) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:869) ~[spring-context-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.boot.web.reactive.context.ReactiveWebServerApplicationContext.refresh(ReactiveWebServerApplicationContext.java:61) ~[spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:780) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:412) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:333) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1277) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1265) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
    at tv.rr.thor.bus.ThorBusApplication.main(ThorBusApplication.java:12) [classes/:na]
Caused by: java.io.FileNotFoundException: file:\C:\thor\thor-service\thor-bus\target\classes\rr-hitube-firebase-adminsdk-ivopy-0743e9a8b3.json (文件名、目录名或卷标语法不正确。)
    at java.io.FileInputStream.open0(Native Method) ~[na:1.8.0_144]
    at java.io.FileInputStream.open(FileInputStream.java:195) ~[na:1.8.0_144]
    at java.io.FileInputStream.<init>(FileInputStream.java:138) ~[na:1.8.0_144]
    at java.io.FileInputStream.<init>(FileInputStream.java:93) ~[na:1.8.0_144]
    at tv.rr.thor.bus.kafka.consumer.KafkaMsgConsumer.initFireBase(KafkaMsgConsumer.java:54) ~[classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_144]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_144]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_144]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_144]
    at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleElement.invoke(InitDestroyAnnotationBeanPostProcessor.java:366) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata.invokeInitMethods(InitDestroyAnnotationBeanPostProcessor.java:309) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:136) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    ... 18 common frames omitted

解决办法是不要转换为File对象，File对象会报路径找不到错误，直接转换为InputStream对象，

错误写法：

        File file = new ClassPathResource("rr-hitube-firebase-adminsdk-ivopy-0743e9a8b3.json").getInputStream();

        FileInputStream serviceAccount = new FileInputStream(googleJson.getInputStream());

正确写法

 @Value(value = "classpath:rr-hitube-firebase-adminsdk-ivopy-0743e9a8b3.json")
    private Resource googleJson;

-----
  FileInputStream serviceAccount = new FileInputStream(googleJson.getInputStream());

jpa 中update 得操作，一般会加上@Modifying，如下

@Modifying
@Query(value = "update t_user_msg_count set REWARD_MSG_COUNT = 0 where user_id = ?1", nativeQuery = true)
@Transactional
Void clearRewardMsgByUserId(Long userId);

不加modifying和加了得区别，和save 和saveaAndFlush 得区别一样，就是告诉Entity Manager做响应得刷新操作

不加可能报以下错误

Caused by: javax.persistence.TransactionRequiredException: Executing an update/delete query
    at org.hibernate.query.internal.AbstractProducedQuery.executeUpdate(AbstractProducedQuery.java:1496) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_144]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_144]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_144]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_144]
    at org.springframework.orm.jpa.SharedEntityManagerCreator$DeferredQueryInvocationHandler.invoke(SharedEntityManagerCreator.java:380) ~[spring-orm-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at com.sun.proxy.$Proxy247.executeUpdate(Unknown Source) ~[na:na]
    at org.springframework.data.jpa.repository.query.JpaQueryExecution$ModifyingExecution.doExecute(JpaQueryExecution.java:256) ~[spring-data-jpa-2.0.10.RELEASE.jar:2.0.10.RELEASE]
    at org.springframework.data.jpa.repository.query.JpaQueryExecution.execute(JpaQueryExecution.java:91) ~[spring-data-jpa-2.0.10.RELEASE.jar:2.0.10.RELEASE]
    at org.springframework.data.jpa.repository.query.AbstractJpaQuery.doExecute(AbstractJpaQuery.java:136) ~[spring-data-jpa-2.0.10.RELEASE.jar:2.0.10.RELEASE]
    at org.springframework.data.jpa.repository.query.AbstractJpaQuery.execute(AbstractJpaQuery.java:125) ~[spring-data-jpa-2.0.10.RELEASE.jar:2.0.10.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:602) ~[spring-data-commons-2.0.10.RELEASE.jar:2.0.10.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:590) ~[spring-data-commons-2.0.10.RELEASE.jar:2.0.10.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:59) ~[spring-data-commons-2.0.10.RELEASE.jar:2.0.10.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:294) ~[spring-tx-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) ~[spring-tx-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) ~[spring-tx-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    ... 174 common frames omitted

idea 没有像eclipse那样close project，但是有一种做法效果类似：

Mark Directory As ->Excluded

这样虽然不会像eclipse 那样close掉，但是会去掉java项目识别，仅仅作为文件夹显示。如果像恢复，

点击---Prject structure----modules ----重新add回来就好

java引用和C++的指针作用是一样的，除了使用语法之外，还有如下两个主要不同

java 引用的可操作性较差，不能像指针那样加减，只能通过他获取对象和修改对象内容，比如C++的指针+3，java是不行的

java 的引用是强类型的，C++的指针可以转换成任何类型，和Java的Object很像，java只能转为基类类型使用。

可以理解为java的引用是阉割了功能的C++指针吧。

eureka 默认开启自我保护模式，导致已经不存在的实例还是会显示再eureka上，并继续提供服务。关闭方法如下：

eureka.server.enable-self-preservation= false

这种情况下，eureka会在一段时间内没有接收到心跳，就删除注册的实例