自定義約束驗證調用的isValid兩次，拋NullPointerException異常

我創建了我用來檢查用戶名驗證一個自定義的約束驗證時，驗證訪問數據庫，並檢查是否記錄已經存在，如果它用正則表達式符合。如果用戶名已經存在，但是當輸入一個有效的輸入（一個不存在的用戶名）時，我得到了相當奇怪的錯誤，因爲驗證器工作正常。它引發了一個NullPointerException。自定義約束驗證調用的isValid兩次，拋NullPointerException異常

我把一個計數器和一些語句，讓我跟蹤這些應用程序崩潰，我將包括堆棧跟蹤。該應用程序似乎在調用initialise和isValid方法兩次，第二次是拋出一個NullPointer。我查看了this question，其中說要將<property name="javax.persistence.validation.mode" value="none"/>添加到我的persistence.xml文件中，我已經完成並且沒有做任何更改。

我想，也許我要禁用此別的地方，因爲我沒有用過我的persistence.xml配置應用程序，而不是使用jpaContext.xml文件。

如果任何人有叱修復/我應該在哪裏尋找到找到一個解決我將不勝感激任何意見/經驗。

定製約束驗證

public class UserNameConstraintValidator implements ConstraintValidator<UserName, String> { 
@Autowired 
private HouseholdService householdService; 

private int counter = 0; 


public void initialize(UserName userName) { 
    System.out.println("counter inside initialize is at count : " + counter); 
} 

public boolean isValid(String userName, ConstraintValidatorContext cxt) { 
    System.out.println(userName); 
    counter ++; 
    System.out.println("counter is at count : " + counter); 

    if(householdService.checkForUser(userName) || userName == null) {  //line 26 
     System.out.println(userName); 
     System.out.println("counter inside if statement is at count : " + counter); 
     return false; 
    } 
    else { 
     System.out.println(userName); 
     System.out.println("counter inside else statement is at count : " + counter); 
     return (userName.matches("^[a-zA-Z0-9]+([a-zA-Z0-9](_|-|)[a-zA-Z0-9])*[a-zA-Z0-9]+$")); 
    } 
} 
}

堆棧跟蹤

 counter inside initialize is at count : 0 
     newUser 
     counter is at count : 1 
     Tue Mar 28 19:18:23 BST 2017 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification. 
     Mar 28, 2017 7:18:23 PM org.hibernate.hql.internal.QueryTranslatorFactoryInitiator initiateService 
     INFO: HHH000397: Using ASTQueryTranslatorFactory 
     Hibernate: select household0_.id as id1_1_, household0_.password as password2_1_, household0_.userName as userName3_1_ from Households household0_ where household0_.userName like ? limit ? 
     Hibernate: select household0_.id as id1_1_, household0_.password as password2_1_, household0_.userName as userName3_1_ from Households household0_ where household0_.userName like ? limit ? 
     inside HouseholdRepository, if statement has returned : 0 
     newUser 
     counter inside else statement is at count : 1 
     Tue Mar 28 19:18:24 BST 2017 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification. 
     Tue Mar 28 19:18:24 BST 2017 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification. 
     Hibernate: select next_val as id_val from hibernate_sequence for update 
     Hibernate: update hibernate_sequence set next_val= ? where next_val=? 
     counter inside initialize is at count : 0 
     newUser 
     counter is at count : 1 
     Mar 28, 2017 7:18:24 PM org.apache.catalina.core.StandardWrapperValve invoke 
     SEVERE: Servlet.service() for servlet [springDispatcherServlet] in context with path [/Bill_Calculator] threw exception [Request processing failed; nested exception is javax.validation.ValidationException: HV000028: Unexpected exception during isValid call.] with root cause 
     java.lang.NullPointerException 
      at com.chrishammer.view.UserNameConstraintValidator.isValid(UserNameConstraintValidator.java:26) 
      at com.chrishammer.view.UserNameConstraintValidator.isValid(UserNameConstraintValidator.java:1) 
      at org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.validateSingleConstraint(ConstraintTree.java:446) 
      at org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.validateConstraints(ConstraintTree.java:127) 
      at org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.validateConstraints(ConstraintTree.java:87) 
      at org.hibernate.validator.internal.metadata.core.MetaConstraint.validateConstraint(MetaConstraint.java:73) 
      at org.hibernate.validator.internal.engine.ValidatorImpl.validateMetaConstraint(ValidatorImpl.java:616) 
      at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraint(ValidatorImpl.java:581) 
      at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForSingleDefaultGroupElement(ValidatorImpl.java:527) 
      at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForDefaultGroup(ValidatorImpl.java:495) 
      at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForCurrentGroup(ValidatorImpl.java:460) 
      at org.hibernate.validator.internal.engine.ValidatorImpl.validateInContext(ValidatorImpl.java:410) 
      at org.hibernate.validator.internal.engine.ValidatorImpl.validate(ValidatorImpl.java:207) 
      at org.hibernate.cfg.beanvalidation.BeanValidationEventListener.validate(BeanValidationEventListener.java:116) 
      at org.hibernate.cfg.beanvalidation.BeanValidationEventListener.onPreInsert(BeanValidationEventListener.java:80) 
      at org.hibernate.action.internal.EntityInsertAction.preInsert(EntityInsertAction.java:205) 
      at org.hibernate.action.internal.EntityInsertAction.execute(EntityInsertAction.java:82) 
      at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:586) 
      at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:460) 
      at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:337) 
      at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:39) 
      at org.hibernate.internal.SessionImpl.doFlush(SessionImpl.java:1428) 
      at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1414) 
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
      at java.lang.reflect.Method.invoke(Method.java:498) 
      at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:298) 
      at com.sun.proxy.$Proxy36.flush(Unknown Source) 
      at com.chrishammer.repository.HouseholdRepositoryImpl.save(HouseholdRepositoryImpl.java:23) 
      at com.chrishammer.service.HouseholdServiceImpl.save(HouseholdServiceImpl.java:24) 
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
      at java.lang.reflect.Method.invoke(Method.java:498) 
      at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:333) 
      at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190) 
      at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157) 
      at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99) 
      at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:282) 
      at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96) 
      at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) 
      at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213) 
      at com.sun.proxy.$Proxy41.save(Unknown Source) 
      at com.chrishammer.controller.CreateAccountController.submitUser(CreateAccountController.java:34) 
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
      at java.lang.reflect.Method.invoke(Method.java:498) 
      at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) 
      at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) 
      at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:116) 
      at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) 
      at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) 
      at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) 
      at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963) 
      at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) 
      at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) 
      at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872) 
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:648) 
      at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) 
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) 
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230) 
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) 
      at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) 
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) 
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) 
      at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) 
      at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) 
      at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:474) 
      at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) 
      at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) 
      at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624) 
      at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) 
      at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349) 
      at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:495) 
      at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) 
      at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:767) 
      at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1347) 
      at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) 
      at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) 
      at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) 
      at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) 
      at java.lang.Thread.run(Thread.java:745)

的persistence.xml

<persistence xmlns="http:://java.sun.com/xml/ns.persistence" 
      xmlns:xsi="http:://www.w3.org/2001/XMLSchema-instance" 
      xsi:schemaLocation="http:://java.sun.com/xml/ns.persistence 
           http:://java.sun.com/xml/ns/persistence_2_0.xsd" 
      version ="2.0" > 


<persistence-unit name="punit"> 
    <property name="javax.persistence.validation.mode" value="none"/> 
</persistence-unit>    



</persistence>

jpaContext.xml

<?xml version="1.0" encoding="UTF-8"?> 
<beans xmlns="http://www.springframework.org/schema/beans" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xmlns:tx="http://www.springframework.org/schema/tx" 
xmlns:context="http://www.springframework.org/schema/context" 
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd 
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd 
    http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd"> 

<context:annotation-config /> 
<context:component-scan base-package="com.chrishammer" /> 
<bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" /> 


<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> 
    <property name="persistenceUnitName" value="punit" /> 
    <property name="dataSource" ref="dataSource" /> 
    <property name="jpaVendorAdapter"> 
     <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"> 
      <property name="showSql" value="true" /> 
     </bean> 
    </property> 
    <property name ="jpaPropertyMap"> 
     <map> 
      <entry key="hibernate.dialect" value="org.hibernate.dialect.MySQL5InnoDBDialect" /> 
      <entry key="hibernate.hbm2ddl.auto" value="update" /> 
      <entry key="hivernate.format_sql" value="true" /> 
     </map> 
    </property> 
</bean> 
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"> 
    <property name="entityManagerFactory" ref="entityManagerFactory" /> 
</bean> 

<tx:annotation-driven /> 

<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> 
    <property name="driverClassName" value="com.mysql.jdbc.Driver" /> 
    <property name="url" value="jdbc:mysql://localhost:3306/testingDb?autoReconnect=true" /> 
    <property name="username" value="root" /> 
    <property name="password" value="root" /> 
</bean> 
</beans>

如果你有什麼事讓我知道，任何幫助，將不勝感激。

來源

2017-03-28 Chris

什麼是第26行？這就是NPE發生的地方。 –

第26行是if語句，用於檢查用戶是否存在。用戶名第一次被傳遞，但由於某種原因，它被調用兩次，第二次拋出異常。我將編輯行號。 – Chris

無助於解決您的問題，但您應該將覆蓋註釋添加到'isValid'。你是否手動調用這個'isValid'？ –

我已經修復了這個問題。雖然翻翻有關休眠Bean驗證的文件中發現here，我注意到，在persistence.xml文件中<property>標籤是由標籤<properties>包圍。簡單地將此添加到我的persistence.xml文件解決了我的問題。

來源

2017-03-30 10:46:44 Chris

自定義約束驗證調用的isValid兩次，拋NullPointerException異常

回答

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