서버 실행시에 이런 오류가 뜨는 이유가 무엇이며 해결법을 알고싶습니다! export 'default' (imported as 'VueRouter') was not found in 'vue-router' 컴파일 오류인데 왜일까요ㅜㅜ>?? 원인::     package.json ::   vue 버전 ::  

어플리케이션 포트는 0~65535까지라고 하는데, 만약 구글서버에서 동시에 100만명의 접속자가 들어오면 클라이언트별로 포트를 다 할당하나요? 그러면 100만명을 수용 못할거 같은데 어떻게 처리하는지 궁금합니다. 만약 포트는 동일한 포트를 쓰고 app단에서 사용자 처리를 한다면 app에서는 100만명의 주소와 포트를 다 관리하는 것인지요?   감사합니다.

영상 23분 36초에 나오는 MyStatComponent.cpp의 OnAttacked(float DamageAmount) 함수에서 DamageAmount 변수는 따로 10이라고 설정해준 적이 없는데 기능 구현되는 것을 보면 10씩 깎이더라구요.  이건 왜 이렇게 되는지 알 수 있을까요? 

궁금해서 질문드립니다. 전세계에서 사용하는 ip주소가 점점 포화상태에 이르고 있잖아요? 스마트폰, 태블릿도 보급되고 서버도 늘어나고 IoT도 점점 늘어나고 있고,,, 아직까지는 ip주소가 넉넉한지 궁금합니다. 그리고 현시점의 ipv6 보급률? 은 어느정도인지, 궁금합니다. 마지막으로 만약 구형 IoT나 네트워크 장비라서 ipv4밖에 인식을 못하는 장비가 있고 마침 전세계 ipv4가 포화되었다고 가정하면 어떻게 이 장비를 네트웍에 연결시킬수 있는지도 궁금하구요.   감사합니다.

c 가 이렇게 선언 되어있어서, 0번째를 출력하고자 해서 출력하면, KeyError: 0 이라고 뜨네요 그리고 만약 c의 'arr'에서 어떠한 원소를 출력하고자 하면 어떻게 작성해야하나요?

플러터와 <php,DB(mysql)>을 사용하여 로그인&회원가입을 구현했습니다.  로그인을 하면 닉네임을 표시하고 싶은데 DB에서 ID에 해당하는 닉네임 값을 어떻게 가져와야할지 모르겠습니다.  로그인하면 로그인유지는 shared_preferences 사용하여 (id,pw)를 저장했습니다.  

위와 같이 calloc을 이용해서 buf를 선언할 경우 read() fail 문제가 발생하는데, 교수님의 코드와 같이 정적 어레이로 선언하면 코드가 정상적으로 돌아가는 것을 확인했습니다. 혹시 calloc으로 설정하면 안되는 이유가 있는지 여쭤보고 싶습니다. 

먼저 좋은 강좌 감사드립니다. 해당 블로그 접속이 되지 않아요.  확인부탁드립니다.

학습하는 분들께 도움이 되고, 더 좋은 답변을 드릴 수 있도록 질문전에 다음을 꼭 확인해 Consider defining a bean of type 'javax.persistence.EntityManagerFactory' in your configuration. 2022-08-17 10:08:40.790 ERROR 13280 --- [           main] o.s.test.context.TestContextManager      : Caught exception while allowing TestExecutionListener [org.springframework.test.context.web.ServletTestExecutionListener@5be49b60] to prepare test instance [repository.MemberRepositoryTest@19f040ba] java.lang.IllegalStateException: Failed to load ApplicationContext    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:132) ~[spring-test-5.3.22.jar:5.3.22]    at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:124) ~[spring-test-5.3.22.jar:5.3.22]    at org.springframework.test.context.web.ServletTestExecutionListener.setUpRequestContextIfNecessary(ServletTestExecutionListener.java:190) ~[spring-test-5.3.22.jar:5.3.22]    at org.springframework.test.context.web.ServletTestExecutionListener.prepareTestInstance(ServletTestExecutionListener.java:132) ~[spring-test-5.3.22.jar:5.3.22]    at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:248) ~[spring-test-5.3.22.jar:5.3.22]    at org.springframework.test.context.junit.jupiter.SpringExtension.postProcessTestInstance(SpringExtension.java:138) ~[spring-test-5.3.22.jar:5.3.22]    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$invokeTestInstancePostProcessors$8(ClassBasedTestDescriptor.java:363) ~[junit-jupiter-engine-5.8.2.jar:5.8.2]    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.executeAndMaskThrowable(ClassBasedTestDescriptor.java:368) ~[junit-jupiter-engine-5.8.2.jar:5.8.2]    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$invokeTestInstancePostProcessors$9(ClassBasedTestDescriptor.java:363) ~[junit-jupiter-engine-5.8.2.jar:5.8.2]    at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:197) ~[na:na]    at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:179) ~[na:na]    at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1625) ~[na:na]    at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509) ~[na:na]    at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499) ~[na:na]    at java.base/java.util.stream.StreamSpliterators$WrappingSpliterator.forEachRemaining(StreamSpliterators.java:310) ~[na:na]    at java.base/java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:735) ~[na:na]    at java.base/java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:734) ~[na:na]    at java.base/java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:762) ~[na:na]    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.invokeTestInstancePostProcessors(ClassBasedTestDescriptor.java:362) ~[junit-jupiter-engine-5.8.2.jar:5.8.2]    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$instantiateAndPostProcessTestInstance$6(ClassBasedTestDescriptor.java:283) ~[junit-jupiter-engine-5.8.2.jar:5.8.2]    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.instantiateAndPostProcessTestInstance(ClassBasedTestDescriptor.java:282) ~[junit-jupiter-engine-5.8.2.jar:5.8.2]    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$testInstancesProvider$4(ClassBasedTestDescriptor.java:272) ~[junit-jupiter-engine-5.8.2.jar:5.8.2]    at java.base/java.util.Optional.orElseGet(Optional.java:364) ~[na:na]    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$testInstancesProvider$5(ClassBasedTestDescriptor.java:271) ~[junit-jupiter-engine-5.8.2.jar:5.8.2]    at org.junit.jupiter.engine.execution.TestInstancesProvider.getTestInstances(TestInstancesProvider.java:31) ~[junit-jupiter-engine-5.8.2.jar:5.8.2]    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$prepare$0(TestMethodTestDescriptor.java:102) ~[junit-jupiter-engine-5.8.2.jar:5.8.2]    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.prepare(TestMethodTestDescriptor.java:101) ~[junit-jupiter-engine-5.8.2.jar:5.8.2]    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.prepare(TestMethodTestDescriptor.java:66) ~[junit-jupiter-engine-5.8.2.jar:5.8.2]    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$prepare$2(NodeTestTask.java:123) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.NodeTestTask.prepare(NodeTestTask.java:123) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:90) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at java.base/java.util.ArrayList.forEach(ArrayList.java:1511) ~[na:na]    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at java.base/java.util.ArrayList.forEach(ArrayList.java:1511) ~[na:na]    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:35) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:54) ~[junit-platform-engine-1.8.2.jar:1.8.2]    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:107) ~[junit-platform-launcher-1.8.2.jar:1.8.2]    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:88) ~[junit-platform-launcher-1.8.2.jar:1.8.2]    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.lambda$execute$0(EngineExecutionOrchestrator.java:54) ~[junit-platform-launcher-1.8.2.jar:1.8.2]    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.withInterceptedStreams(EngineExecutionOrchestrator.java:67) ~[junit-platform-launcher-1.8.2.jar:1.8.2]    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:52) ~[junit-platform-launcher-1.8.2.jar:1.8.2]    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:114) ~[junit-platform-launcher-1.8.2.jar:1.8.2]    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:86) ~[junit-platform-launcher-1.8.2.jar:1.8.2]    at org.junit.platform.launcher.core.DefaultLauncherSession$DelegatingLauncher.execute(DefaultLauncherSession.java:86) ~[junit-platform-launcher-1.8.2.jar:1.8.2]    at org.junit.platform.launcher.core.SessionPerRequestLauncher.execute(SessionPerRequestLauncher.java:53) ~[junit-platform-launcher-1.8.2.jar:1.8.2]    at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:57) ~[junit5-rt.jar:na]    at com.intellij.rt.junit.IdeaTestRunner$Repeater$1.execute(IdeaTestRunner.java:38) ~[junit-rt.jar:na]    at com.intellij.rt.execution.junit.TestsRepeater.repeat(TestsRepeater.java:11) ~[idea_rt.jar:na]    at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:35) ~[junit-rt.jar:na]    at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:235) ~[junit-rt.jar:na]    at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54) ~[junit-rt.jar:na]Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'memberRepository': Injection of persistence dependencies failed; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'javax.persistence.EntityManagerFactory' available    at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor.postProcessProperties(PersistenceAnnotationBeanPostProcessor.java:351) ~[spring-orm-5.3.22.jar:5.3.22]    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1431) ~[spring-beans-5.3.22.jar:5.3.22]    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:619) ~[spring-beans-5.3.22.jar:5.3.22]    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.22.jar:5.3.22]    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.22.jar:5.3.22]    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.22.jar:5.3.22]    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.22.jar:5.3.22]    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.22.jar:5.3.22]    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:955) ~[spring-beans-5.3.22.jar:5.3.22]    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:918) ~[spring-context-5.3.22.jar:5.3.22]    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) ~[spring-context-5.3.22.jar:5.3.22]    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:734) ~[spring-boot-2.7.2.jar:2.7.2]    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:408) ~[spring-boot-2.7.2.jar:2.7.2]    at org.springframework.boot.SpringApplication.run(SpringApplication.java:308) ~[spring-boot-2.7.2.jar:2.7.2]    at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:132) ~[spring-boot-test-2.7.2.jar:2.7.2]    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:99) ~[spring-test-5.3.22.jar:5.3.22]    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:124) ~[spring-test-5.3.22.jar:5.3.22]    ... 71 common frames omittedCaused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'javax.persistence.EntityManagerFactory' available    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveNamedBean(DefaultListableBeanFactory.java:1221) ~[spring-beans-5.3.22.jar:5.3.22]    at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor.findDefaultEntityManagerFactory(PersistenceAnnotationBeanPostProcessor.java:565) ~[spring-orm-5.3.22.jar:5.3.22]    at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor.findEntityManagerFactory(PersistenceAnnotationBeanPostProcessor.java:528) ~[spring-orm-5.3.22.jar:5.3.22]    at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor$PersistenceElement.resolveEntityManager(PersistenceAnnotationBeanPostProcessor.java:696) ~[spring-orm-5.3.22.jar:5.3.22]    at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor$PersistenceElement.getResourceToInject(PersistenceAnnotationBeanPostProcessor.java:669) ~[spring-orm-5.3.22.jar:5.3.22]    at org.springframework.beans.factory.annotation.InjectionMetadata$InjectedElement.inject(InjectionMetadata.java:228) ~[spring-beans-5.3.22.jar:5.3.22]    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:119) ~[spring-beans-5.3.22.jar:5.3.22]    at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor.postProcessProperties(PersistenceAnnotationBeanPostProcessor.java:348) ~[spring-orm-5.3.22.jar:5.3.22]    ... 87 common frames omitted java.lang.IllegalStateException: Failed to load ApplicationContext     at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:132)    at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:124)    at org.springframework.test.context.web.ServletTestExecutionListener.setUpRequestContextIfNecessary(ServletTestExecutionListener.java:190)    at org.springframework.test.context.web.ServletTestExecutionListener.prepareTestInstance(ServletTestExecutionListener.java:132)    at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:248)    at org.springframework.test.context.junit.jupiter.SpringExtension.postProcessTestInstance(SpringExtension.java:138)    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$invokeTestInstancePostProcessors$8(ClassBasedTestDescriptor.java:363)    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.executeAndMaskThrowable(ClassBasedTestDescriptor.java:368)    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$invokeTestInstancePostProcessors$9(ClassBasedTestDescriptor.java:363)    at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:197)    at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:179)    at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1625)    at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509)    at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)    at java.base/java.util.stream.StreamSpliterators$WrappingSpliterator.forEachRemaining(StreamSpliterators.java:310)    at java.base/java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:735)    at java.base/java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:734)    at java.base/java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:762)    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.invokeTestInstancePostProcessors(ClassBasedTestDescriptor.java:362)    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$instantiateAndPostProcessTestInstance$6(ClassBasedTestDescriptor.java:283)    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.instantiateAndPostProcessTestInstance(ClassBasedTestDescriptor.java:282)    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$testInstancesProvider$4(ClassBasedTestDescriptor.java:272)    at java.base/java.util.Optional.orElseGet(Optional.java:364)    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$testInstancesProvider$5(ClassBasedTestDescriptor.java:271)    at org.junit.jupiter.engine.execution.TestInstancesProvider.getTestInstances(TestInstancesProvider.java:31)    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$prepare$0(TestMethodTestDescriptor.java:102)    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.prepare(TestMethodTestDescriptor.java:101)    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.prepare(TestMethodTestDescriptor.java:66)    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$prepare$2(NodeTestTask.java:123)    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)    at org.junit.platform.engine.support.hierarchical.NodeTestTask.prepare(NodeTestTask.java:123)    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:90)    at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41)    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155)    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)    at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41)    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155)    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:35)    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)    at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:54)    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:107)    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:88)    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.lambda$execute$0(EngineExecutionOrchestrator.java:54)    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.withInterceptedStreams(EngineExecutionOrchestrator.java:67)    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:52)    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:114)    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:86)    at org.junit.platform.launcher.core.DefaultLauncherSession$DelegatingLauncher.execute(DefaultLauncherSession.java:86)    at org.junit.platform.launcher.core.SessionPerRequestLauncher.execute(SessionPerRequestLauncher.java:53)    at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:57)    at com.intellij.rt.junit.IdeaTestRunner$Repeater$1.execute(IdeaTestRunner.java:38)    at com.intellij.rt.execution.junit.TestsRepeater.repeat(TestsRepeater.java:11)    at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:35)    at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:235)    at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'memberRepository': Injection of persistence dependencies failed; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'javax.persistence.EntityManagerFactory' available    at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor.postProcessProperties(PersistenceAnnotationBeanPostProcessor.java:351)    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1431)    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:619)    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542)    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335)    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333)    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208)    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:955)    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:918)    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583)    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:734)    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:408)    at org.springframework.boot.SpringApplication.run(SpringApplication.java:308)    at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:132)    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:99)    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:124)    ... 71 moreCaused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'javax.persistence.EntityManagerFactory' available    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveNamedBean(DefaultListableBeanFactory.java:1221)    at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor.findDefaultEntityManagerFactory(PersistenceAnnotationBeanPostProcessor.java:565)    at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor.findEntityManagerFactory(PersistenceAnnotationBeanPostProcessor.java:528)    at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor$PersistenceElement.resolveEntityManager(PersistenceAnnotationBeanPostProcessor.java:696)    at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor$PersistenceElement.getResourceToInject(PersistenceAnnotationBeanPostProcessor.java:669)    at org.springframework.beans.factory.annotation.InjectionMetadata$InjectedElement.inject(InjectionMetadata.java:228)    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:119)    at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor.postProcessProperties(PersistenceAnnotationBeanPostProcessor.java:348)    ... 87 more Process finished with exit code -1       에제보고 따라해봤는데 왜 빈을 못찾을까요.?

선생님 안녕하세요   현재 머신러닝강의부터 CNN강의까지 선생님강의를 듣고잇는 열혈팬입니다 ㅎ 선생님강의중에 SQL, spark등도 잇던데, 이에관해서는 아는게 전혀 없어서 조언받고 싶어서 이 사이트에서 질문을 드립니다. 알고싶은것은 각각의SQL, spark의 역할입니다 ㅎ(앞으로 강의 들을 생각이라서....)   1) SQL은 데이터 분석용이고 실제 목표값을 예측할수는 없고 목표값을 예측하기위해서는 머신러닝을 이해해야한다고 이해를 해도 되는지요?   2) spark 은 기업에서실제 빅데이터를 이용할경우 사용하는 도구로서 spark을 활용해서 머신러닝을 구현해야 한다고 이해를 해도 되는지요? (물론 데이터가 적을경우 엑셀파일로 받아서 파이썬으로 머신러닝을 구현하면 되지만...)   3) 데이터분석가로서는 최종목표를 spark등을 이용한 머신러닝을 구축하는것이 최종목표로 잡아도 되는지요?   바쁘시겟지만, 시간나실때 답변부탁드리겟습니다 ㅎ      

등록은 되는데 리스트에서 조회가 되지 않습니다.   MemberController.java package hello.hellospring.controller;import hello.hellospring.domain.Member;import hello.hellospring.service.MemberService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Controller;import org.springframework.ui.Model;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.PostMapping;import java.util.List;@Controller// memberController객체를 생성해서 Spring에 넣어둠public class MemberController {private final MemberService memberService;@Autowired//생성자에 Autowired라고 되어 있으면 memberService를 Spring 컨테이너에 연결public MemberController(MemberService memberService) {this.memberService = memberService;}@GetMapping("/members/new")public String createForm(){return "members/createMemberForm";}@PostMapping("/members/new")public String create(MemberForm form){Member member = new Member();member.setName(form.getName());//System.out.println("member = " + member.getName());memberService.join(member);return "redirect:/";}@GetMapping("/members")public String list(Model model){List<Member> members = memberService.findMembers();//Model들을 다 가져올 수 있음model.addAttribute("members", members);return "members/memberList";}}memberList.html <!DOCTYPE HTML><html xmlns:th="http://www.thymeleaf.org"><body><div class="container"><div><table><thead><tr><th>#</th><th>이름</th></tr></thead><tbody><tr th:each="member : ${members}"><td th:text="${member.id}"></td><td th:text="${member.name}"></td></tr></tbody></table></div></div> <!-- /container --></body></html>     해당 질문이 좀 많은 거 봐서 나중에 보완을 하시면 더 좋을 거 같다는 생각도 듭니다

저는 ServletAppContext.java 파일에서 에러가 납니다. The type ServletAppContext must implement the inherited abstract method WebMvcConfigurer.configureMessageConverters(List<HttpMessageConverter<?>>)   Cannot directly invoke the abstract method configureViewResolvers(ViewResolverRegistry) for the type WebMvcConfigurer   위 두가지 에러가 나옵니다. 어떻게 해결해야하나요?  

강사님 안녕하세요, js와 node를 같이 공부중인데요.. 교재에서 궁금한 부분이 생겨 질문드립니다.   const parseCookies = (cookie = '') => cookie .split(';') .map(v=>v.split('=')) .....   상기 코드에서 (cookie='')를 (cookie) 로 넘겨주어도 되던데, 코드에서 (cookie='')로 작성하신 이유가 궁금합니다.   감사합니다.

- 인프런 아이디 : superdols37 - 인프런 이메일 : superdols37@gmail.com - 깃헙 아이디 : superdols37@gmail.com - 깃헙 Username : superdols

15일 전에 질문을 작성하였는데 못 보신 것 같아서 다시 글 올립니다. 밑의 글은 예전 글을 그대로 가져왔습니다.   순환참조를 해결하기 위해서 forwardRef를 사용하는 것은 알겠습니다. 그런데 어떻게 동작하길래 이 함수가 순환참조 문제를 해결할 수 있는 것인가요? 이름만 들어서는 참조를 앞으로 한다는 것 같은데 구체적으로 어떻게 동작하는지 궁금합니다.

@charset "utf-8"; body {     margin: 0;     background-color: #ffffff;     color: #333333;     font-size: 15px; } a {     color: #333333;     text-decoration: none; } .container {} .header-inner {     border: 1px solid blueviolet; } header {     height: 100px;     width: 1200px;     margin: auto; } header > div {     border: 1px solid green;     height: 100px; } .header-logo {     width: 200px;     float: left; } .navi {     width: 800px;     float: right; } .content-inner {} .slide {     width: 1200px;     margin: auto; } .slide > div {     border: 1px solid red;     height: 300px; } .items {} .items > div {} .news {} .gallery {} .banner {} .footer-inner {} footer {} footer > div {} .copyright {} .copyright > div {} .family-site {}   레이아웃을 짜고 있는데 slide 높이값을 주니까 header-inner 의 보더값이 그대로 커집니다. 그래서 header-inner 에 height : 100px; 을 주니까 정상적으로 되는데. 이렇게 해도 문제가 없는지요? 근데 왜 똑같이 했는데 제건 header-inner 에 높이값을 줘야지만 정상작동 되는지 궁금합니다ㅠㅠ    

안녕하세요, 영한님 제가 오해하고 있는건지, 강의 내용 중 tomcat이 웹서버라 표현이 되어있습니다 혹시 tomcat 이 WEB 서버가 아니라, WAS 서버 가 아니였는지요.... WEB 서버 따로, WAS 서버 따로 라고 알고 있었는데.. 제가 잘 몰라서 이렇게 질문 남깁니다..  

강의에서 OptionalInt같은 primitive type에서 사용할 수 있는 Optional 클래스들을 언급해 주셨는데, 이러한 타입을 사용하는 이유는 무엇일까요? 제 생각에는 Optional로 감싸는 것 또한 Integer로 박싱-언박싱하는 것과 비슷해 보이기도 하고, 또 primitive type은 null이 될 수 없지만 OptionalInt 자체가 null인 경우가 발생한다던지.. 여러가지 문제가 발생할 수 있을 것 같거든요 그런데도 primitive type에 Optional 클래스를 만들어둔 이유가 있을까요?

String::compareToIgnoreCase를 변수에 할당하면 BiFunction<String, String, Integer> 타입이 될 줄 알았는데, intellij의 자동완성 기능을 써보니 Comparator<String> 타입이 나왔습니다.  반대로 Comparator타입 변수에 BiFunction은 할당하지 못하는 걸로 봐서 Comparator가 BiFunction을 상속받고 있는 것 같은데, 실제 코드를 보면 상속과 관련된 부분이 없는 것 같네요. @FunctionalInterface 어노테이션이 상속관계를 만들어주는 것인지, 아니면 다른 상속 방법이 있는 것인지 궁금합니다.

 db.User.belongsToMany(db.User, {       through: "Follow",       as: "Followers",       foreignKey: "FollowingId",     });   이 부분에 해당하는 테이블에서 through가 중간 테이블 이름을 나타내고, foreignKey가 row 요소가 되었고, as는 안 쓰였습니다.   db.Post.belongsTo(db.Post, { as: "Retweet" }); 에서는 as가 사용되었는데 왜 이 때만 사용되었는지 모르겠습니다.   혹시 belongsTo에서 row를 넣을 때는 as를, belongsToMany에서 row를 넣을 때는 foreignKey를 사용해야 하나요?