org.springframework.web.util.NestedServletException：请求处理失败;嵌套异常是org.springframework.dao.InvalidDataAccessApiUsageException：目标对象不能为null;嵌套异常是java.lang.IllegalArgumentException异常：目标对象不能在org.springframework.web.servlet.FrameworkServlet.processRequest（FrameworkServlet.java:982）在org.springframework.web.servlet.FrameworkServlet.doPost（FrameworkServlet.java为空：872）在javax.servlet.http.HttpServlet.service（HttpServlet.java:648）在org.springframework.web.servlet.FrameworkServlet.service（FrameworkServlet.java:846）在javax.servlet.http.HttpServlet.service（ HttpServlet.java:729）维持在org.apache.tomcat在org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:165 org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:230）） org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:192）中的.websocket.server.WsFilter.doFilter（WsFilter.java:52）位于org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java） ：165）在org.springframework.security.web.FilterChainProxy $ Vir位于org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter的org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke（FilterSecurityInterceptor.java:127）中的tualFilterChain.doFilter（FilterChainProxy.java:317） FilterOcurityInterceptor.java：91）org.springframework.security.web.FilterChainProxy $ VirtualFilterChain.doFilter（FilterChainProxy.java:331）atg.springframework.security.web.access.ExceptionTranslationFilter.doFilter（ExceptionTranslationFilter.java:115）at org位于org.springframework.security.web.FilterChainProxy的org.springframework.security.web.session.SessionManagementFilter.doFilter（SessionManagementFilter.java:137）中的.springframework.security.web.FilterChainProxy $ VirtualFilterChain.doFilter（FilterChainProxy.java:331） $ VirtualFilterChain.doFilter（FilterChainProxy.java:331）在org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter（AnonymousAuthenticationFilter.java:111）在org.springframework位于org.springframework.security.web.FilterChainProxy的org.springframework.security.web.authentication.rememberme.RememberMeAuthenticationFilter.doFilter（RememberMeAuthenticationFilter.java:150）上的.security.web.FilterChainProxy $ VirtualFilterChain.doFilter（FilterChainProxy.java:331）位于org.springframework.security.web.FilterChainProxy $ VirtualFilterChain.doFilter（FilterChainProxy.java）的org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter（SecurityContextHolderAwareRequestFilter.java:169）上的$ VirtualFilterChain.doFilter（FilterChainProxy.java:331） ：331）在org.springframework的org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter（RequestCacheAwareFilter.java:63）org.springframework.security.web.FilterChainProxy $ VirtualFilterChain.doFilter（FilterChainProxy.java:331） . org.springframework.security.web.Fi上的security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter（AbstractAuthenticationProcessingFilter.java:200） lterChainProxy $ VirtualFilterChain.doFilter（FilterChainProxy.java:331）org.springframework.security.web.authentication.logout.LogoutFilter.doFilter（LogoutFilter.java:121）org.springframework.security.web.FilterChainProxy $ VirtualFilterChain.doFilter（ FilterChainProxy.java:331）org.springframework上的org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal（HeaderWriterFilter.java:66）org.springframework.web.filter.OncePerRequestFilter.doFilter（OncePerRequestFilter.java:107） org.springframework.security.web.FilterChainProxy $ VirtualFilterChain上的.security.web.FilterChainProxy $ VirtualFilterChain.doFilter（FilterChainProxy.java:331）org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter（SecurityContextPersistenceFilter.java:105） .doFilter（FilterChainProxy.java:331）在org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal（WebAsyncManagerIntegrationFilter.java:56）在org.springframework位于org.springframework.security.web.FilterChainProxy.doFilterInternal（FilterChainProxy）的org.springframework.security.web.FilterChainProxy $ VirtualFilterChain.doFilter（FilterChainProxy.java:331）中的.web.filter.OncePerRequestFilter.doFilter（OncePerRequestFilter.java:107）的.java：214）在org.springframework.security.web.FilterChainProxy.doFilter（FilterChainProxy.java:177）在org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate（DelegatingFilterProxy.java:346）在org.springframework.web . filter.DelegatingFilterProxy.doFilter（DelegatingFilterProxy.java:262）atg.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:192）atorg.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:165）org.springframework.web.filter.RequestContextFilter.doFilterInternal（RequestContextFilter.java:99）at org.springframework.web.filter.OncePerRequestFilter.doFilter（ OncePerRequestFilter.java:107）维持在org.springframework.web在org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:165 org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:192）） .filter.HttpPutFormContentFilter.doFilterInternal（HttpPutFormContentFilter.java:89）org.apringframework.web.filter.OncePerRequestFilter.doFilter（OncePerRequestFilter.java:107）org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:192） ）在在org.springf在org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal（HiddenHttpMethodFilter.java:77 org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:165）） orme.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:192）中的ramework.web.filter.OncePerRequestFilter.doFilter（OncePerRequestFilter.java:107）位于org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain . Java的：165）在org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal（CharacterEncodingFilter.java:197）在org.springframework.web.filter.OncePerRequestFilter.doFilter（OncePerRequestFilter.java:107）在org.apache.catalina.core .ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:192）在org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:165）在com.userfront.config.RequestFilter.doFilter（RequestFilter.java:31）在有机apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:192）在org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:165）在org.apache.catalina.core.StandardWrapperValve.invoke（STANDAR dWrapperValve.java:198）在org.apache.catalina.core.StandardContextValve.invoke（StandardContextValve.java:108）在org.apache.catalina.authenticator.AuthenticatorBase.invoke（AuthenticatorBase.java:472）在org.apache.catalina .core.StandardHostValve.invoke（StandardHostValve.java:140）在org.apache.catalina.valves.ErrorReportValve.invoke（ErrorReportValve.java:79）在org.apache.catalina.core.StandardEngineValve.invoke（StandardEngineValve.java:87 ）在org.apache.catalina.connector.CoyoteAdapter.service（CoyoteAdapter.java:349）在org.apache.coyote.http11.Http11Processor.service（Http11Processor.java:784）在org.apache.coyote.AbstractProcessorLight.process（ AbstractProcessorLight.java:66）在org.apache.coyote.AbstractProtocol $ ConnectionHandler.process（AbstractProtocol.java:802）在org.apache.tomcat.util.net.NioEndpoint $ SocketProcessor.doRun（NioEndpoint.java:1410）在组织java.util.concurrent.ThreadPoolExecutor.runWorker中的.apache.tomcat.util.net.SocketProcessorBase.run（SocketProcessorBase.java:49） （来源不明）在java.util.concurrent.ThreadPoolExecutor中的$ Worker.run（来源不明）在org.apache.tomcat.util.threads.TaskThread $ WrappingRunnable.run（TaskThread.java:61）在java.lang.Thread中 . run（Unknown Source）引起：org.springframework.dao.InvalidDataAccessApiUsageException：目标对象不能为null;嵌套异常是java.lang.IllegalArgumentException：在org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible（HibernateJpaDialect）的org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible（EntityManagerFactoryUtils.java:384）中，目标对象不能为null . .java：246）atg.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible（AbstractEntityManagerFactoryBean.java:491）org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible（ChainedPersistenceExceptionTranslator.java：59）org.springframework.dao . 位于org.springframework.aop.framework.ReflectiveMethodInvocation.proceed（ReflectiveMethodInvocation.java:179）的org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke（PersistenceExceptionTranslationInterceptor.java:147）中的support.DataAccessUtils.translateIfNecessary（DataAccessUtils.java:213）在org.springframework.data.jpa.repos位于org.springframework.aop.framework.ReflectiveMethodInvocation.proceed（ReflectiveMethodInvocation.java:179）org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke（ExposeInvocationInterceptor . ）中的itory.support.CrudMethodMetadataPostProcessor $ CrudMethodMetadataPopulatingMethodInterceptor.invoke（CrudMethodMetadataPostProcessor.java：133） . Java的：92）在org.springframework.aop.framework.ReflectiveMethodInvocation.proceed（ReflectiveMethodInvocation.java:179）在org.springframework.aop.framework.JdkDynamicAopProxy.invoke（JdkDynamicAopProxy.java:213）在com.sun.proxy $ Proxy96.save（未知来源）atcom.userfront.service.UserServiceImpl.UserServiceImpl.createUser（UserServiceImpl.java:61）at com.userfront.service.UserServiceImpl.UserServiceImpl $$ FastClassBySpringCGLIB $$ 30f0fe10.invoke（）at org.springframework.cglib.proxy.MethodProxy.invoke （MethodProxy.java:204）org.springframework.aop.framework.CglibAopProxy $ CglibMethodInvocation.invokeJoinpoint（CglibAopProxy.java:720）org.springframework.aop.framework.ReflectiveMethodInvocation.proceed（ReflectiveMethodInvocation.java:157）at org . springframework.transaction.interceptor.TransactionInterceptor $ 1.proceedWithInvocation（TransactionInterceptor.java:99）在org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction（TransactionAspectSupport.java:281）在org.springframework.transaction.interceptor.TransactionInterceptor.invoke（TransactionInterceptor .java：96）在org.springframework.aop.framework的org.springframework.aop.framework.ReflectiveMethodInvocation.proceed（ReflectiveMethodInvocation.java:179） . CglibAopProxy $ DynamicAdvisedInterceptor.intercept（CglibAopProxy.java:655）在com.userfront.service.UserServiceImpl.UserServiceImpl $$ EnhancerBySpringCGLIB $$ f80e75a3.createUser（）在com.userfront.controller.HomeController.signupPost（HomeController.java:70）在sun.reflect.NativeMethodAccessorImpl.invoke0（Native Method）at sun.reflect.NativeMethodAccessorImpl.invoke（Unknown Source）at sun.reflect.DelegatingMethodAccessorImpl.invoke（Unknown Source）at java.lang.reflect.Method.invoke（Unknown Source）at at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke（InvocableHandlerMethod.java:221）位于org.springframework.web.servlet的org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest（InvocableHandlerMethod.java:136） . mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle（ServletInvocableHandlerMethod.java:114）在org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod（RequestMappingHandlerAdapter.j AVA：827）在org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal（RequestMappingHandlerAdapter.java:738）在org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle（AbstractHandlerMethodAdapter.java： 85）在org.springframework.web.servlet.DispatcherServlet.doDispatch（DispatcherServlet.java:963）在org.springframework.web.servlet.DispatcherServlet.doService（DispatcherServlet.java:897）在org.springframework.web.servlet.FrameworkServlet .processRequest（FrameworkServlet.java：970）... 78更多引起：java.lang.IllegalArgumentException：在org.springframework的org.springframework.util.Assert.notNull（Assert.java:115）中，目标对象不能为null .beans.AbstractNestablePropertyAccessor.setWrappedInstance（AbstractNestablePropertyAccessor.java:205）org.springframework.beans.BeanWrapperImpl.setWrappedInstance（BeanWrapperImpl.java:151）org.springframework.beans.AbstractNestablePropertyAccessor.setWrappedInstance（AbstractN） establePropertyAccessor.java:194）org.springframework.beans.AbstractNestablePropertyAccessor . （AbstractNestablePropertyAccessor.java:133）org.springframework.beans.BeanWrapperImpl . （BeanWrapperImpl.java:101）org.springframework.data.util.DirectFieldAccessFallbackBeanWrapper . （ DirectFieldAccessFallbackBeanWrapper.java:35）org.springframework.data.jpa.repository.support.JpaMetamodelEntityInformation.getId(JpaMetamodelEntityInformation.java:146）org.springframework.data.repository.core.support.AbstractEntityInformation.isNew（AbstractEntityInformation.java： 51）atg.springframework.data.jpa.repository.support.JpaMetamodelEntityInformation.isNew（JpaMetamodelEntityInformation.java:225）at org.springframework.data.jpa.repository.support.SimpleJpaRepository.save（SimpleJpaRepository.java:505）at sun位于sun.reflect.DelegatingMethodAccessorImpl.invoke（未知来源）的sun.reflect.NativeMethodAccessorImpl.invoke（未知来源）的.reflect.NativeMethodAccessorImpl.invoke0（本地方法）在org.springframework.data.repository.core.support.RepositoryFactorySupport的$ java.lang.reflect.Method.invoke（未知来源）org.springframework.data.repository.core上的$ QueryExecutorMethodInterceptor.executeMethodOn（RepositoryFactorySupport.java:503） . support.RepositoryFactorySupport $ QueryExecutorMethodInterceptor.doInvoke（RepositoryFactorySupport.java:488）org.springframework.data.repository.core.support.RepositoryFactorySupport $ QueryExecutorMethodInterceptor.invoke（RepositoryFactorySupport.java:460）org.springframework.aop.framework.ReflectiveMethodInvocation . 在org.springframework的org.springframework.aop.framework.ReflectiveMethodInvocation.proceed（ReflectiveMethodInvocation.java:179）的org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke（DefaultMethodInvokingMethodInterceptor.java:61）上进行（ReflectiveMethodInvocation.java:179） .transaction.interceptor.TransactionInterceptor $ 1.proceedWithInvocation（TransactionInterceptor.java:99）atOrg.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction（TransactionAspectSupport.java:281）位于org.springframework.aop.framework.ReflectiveMethodInvocation.proceed的org.springframework.transaction.interceptor.TransactionInterceptor.invoke（TransactionInterceptor.java:96） ReflectiveMethodInvocation.java:179）org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke（PersistenceExceptionTranslationInterceptor.java:136）... 110 more