Spring Boot - 为什么userRepository实例在调用save方法后变为null？

时间：2018-03-31 19:28:46

标签： java spring spring-boot spring-data-jpa

我正在使用Spring Boot与我的网络应用程序进行注册，并与MySQL建立数据库连接。为了检查给定的用户名是否正在使用，我创建了自己的验证注释。我传递有效数据并发生此错误：

| 27-07-1955 | NULL |

看起来Spring检查验证，bindingResult没有任何错误，所以调用userRepository.save（），然后再次转到UniqueLoginValidator，然后userRepository为null。

MainController ：

2018-03-31 20:47:43.992  INFO 13476 --- [nio-8080-exec-1] 
o.s.web.servlet.DispatcherServlet        : FrameworkServlet 
'dispatcherServlet': initialization completed in 34 ms
in UniqueLoginValidator: isValid
somelogin
org.springframework.data.jpa.repository.support.SimpleJpaRepository@28ffeaf5
2018-03-31 20:48:12.486  INFO 13476 --- [nio-8080-exec-3] 
o.h.h.i.QueryTranslatorFactoryInitiator  : HHH000397: Using 
ASTQueryTranslatorFactory
Optional.empty
MainController: checkUserInfo before saving data
in UniqueLoginValidator: isValid
somelogin
2018-03-31 20:48:12.779 ERROR 13476 --- [nio-8080-exec-3] 
o.h.i.ExceptionMapperStandardImpl        : HHH000346: Error during managed 
flush [HV000028: Unexpected exception during isValid call.]
2018-03-31 20:48:12.789 ERROR 13476 --- [nio-8080-exec-3] o.a.c.c.C.[.[.[/].
[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] 
in context with path [] threw exception [Request processing failed; nested 
exception is org.springframework.transaction.TransactionSystemException: 
Could not commit JPA transaction; nested exception is 
javax.persistence.RollbackException: Error while committing the transaction] 
with root cause

java.lang.NullPointerException: null
at app.user.UniqueLoginValidator.isValid(UniqueLoginValidator.java:30) ~[main/:na]
at app.user.UniqueLoginValidator.isValid(UniqueLoginValidator.java:1) ~[main/:na]
at org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.validateSingleConstraint(ConstraintTree.java:357) ~[hibernate-validator-6.0.7.Final.jar:6.0.7.Final]
at org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.validateConstraints(ConstraintTree.java:126) ~[hibernate-validator-6.0.7.Final.jar:6.0.7.Final]
at org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.validateConstraints(ConstraintTree.java:86) ~[hibernate-validator-6.0.7.Final.jar:6.0.7.Final]
at org.hibernate.validator.internal.metadata.core.MetaConstraint.doValidateConstraint(MetaConstraint.java:116) ~[hibernate-validator-6.0.7.Final.jar:6.0.7.Final]
at org.hibernate.validator.internal.metadata.core.MetaConstraint.validateConstraint(MetaConstraint.java:109) ~[hibernate-validator-6.0.7.Final.jar:6.0.7.Final]
at org.hibernate.validator.internal.engine.ValidatorImpl.validateMetaConstraint(ValidatorImpl.java:534) ~[hibernate-validator-6.0.7.Final.jar:6.0.7.Final]
at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForSingleDefaultGroupElement(ValidatorImpl.java:497) ~[hibernate-validator-6.0.7.Final.jar:6.0.7.Final]
at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForDefaultGroup(ValidatorImpl.java:466) ~[hibernate-validator-6.0.7.Final.jar:6.0.7.Final]
at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForCurrentGroup(ValidatorImpl.java:431) ~[hibernate-validator-6.0.7.Final.jar:6.0.7.Final]
at org.hibernate.validator.internal.engine.ValidatorImpl.validateInContext(ValidatorImpl.java:381) ~[hibernate-validator-6.0.7.Final.jar:6.0.7.Final]
at org.hibernate.validator.internal.engine.ValidatorImpl.validate(ValidatorImpl.java:170) ~[hibernate-validator-6.0.7.Final.jar:6.0.7.Final]
at org.hibernate.cfg.beanvalidation.BeanValidationEventListener.validate(BeanValidationEventListener.java:116) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
at org.hibernate.cfg.beanvalidation.BeanValidationEventListener.onPreInsert(BeanValidationEventListener.java:80) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
at org.hibernate.action.internal.EntityInsertAction.preInsert(EntityInsertAction.java:205) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
at org.hibernate.action.internal.EntityInsertAction.execute(EntityInsertAction.java:82) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:599) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:473) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:337) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:39) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
at org.hibernate.internal.SessionImpl.doFlush(SessionImpl.java:1436) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:493) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
at org.hibernate.internal.SessionImpl.flushBeforeTransactionCompletion(SessionImpl.java:3206) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
at org.hibernate.internal.SessionImpl.beforeTransactionCompletion(SessionImpl.java:2412) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
at org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.beforeTransactionCompletion(JdbcCoordinatorImpl.java:473) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.beforeCompletionCallback(JdbcResourceLocalTransactionCoordinatorImpl.java:156) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.access$100(JdbcResourceLocalTransactionCoordinatorImpl.java:38) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.commit(JdbcResourceLocalTransactionCoordinatorImpl.java:231) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
at org.hibernate.engine.transaction.internal.TransactionImpl.commit(TransactionImpl.java:68) ~[hibernate-core-5.2.14.Final.jar:5.2.14.Final]
at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:536) ~[spring-orm-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:746) ~[spring-tx-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:714) ~[spring-tx-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:532) ~[spring-tx-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:304) ~[spring-tx-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) ~[spring-tx-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) ~[spring-tx-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:135) ~[spring-data-jpa-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) ~[spring-aop-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:61) ~[spring-data-commons-2.0.5.RELEASE.jar:2.0.5.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at com.sun.proxy.$Proxy94.save(Unknown Source) ~[na:na]
at app.MainController.checkUserInfo(MainController.java:34) ~[main/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_161]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_161]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_161]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_161]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:870) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:776) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:978) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:881) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:661) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:855) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.28.jar:8.5.28]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) ~[tomcat-embed-core-8.5.28.jar:8.5.28]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.28.jar:8.5.28]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:496) [tomcat-embed-core-8.5.28.jar:8.5.28]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.28.jar:8.5.28]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.28.jar:8.5.28]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.28.jar:8.5.28]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.28.jar:8.5.28]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803) [tomcat-embed-core-8.5.28.jar:8.5.28]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.28.jar:8.5.28]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790) [tomcat-embed-core-8.5.28.jar:8.5.28]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459) [tomcat-embed-core-8.5.28.jar:8.5.28]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.28.jar:8.5.28]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_161]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_161]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.28.jar:8.5.28]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_161]

UniqueLogin ：

package app;
import javax.validation.Valid;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;

import app.user.User;
import app.user.UserRepository;

@Controller
@RequestMapping("/")
public class MainController {

    @Autowired
    private UserRepository userRepository;

    @GetMapping("/")
    public String addNewUserForm(User user) {
        return "sign-up";
    }

    @PostMapping("/")
    public String checkUserInfo(@Valid@ModelAttribute(value="user") User 
    user, BindingResult bindingResult) {

    if(bindingResult.hasErrors()) {
        return "sign-up";
    }
    System.out.println("MainController: checkUserInfo before saving data");
    userRepository.save(user);
    System.out.println("MainController: checkUserInfo after saving data");
    return "redirect:/home";
    }
}

UniqueLoginValidator ：

package app.user;

import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import javax.validation.Constraint;
import javax.validation.Payload;

@Retention(RUNTIME)
@Target({ FIELD, METHOD })
@Constraint(validatedBy = UniqueLoginValidator.class)
public @interface UniqueLogin {
    String message() default "{UniqueLogin.message}";
    Class<?>[] groups() default {};
    Class<? extends Payload>[] payload() default {};
}

UserRepository ：

package app.user;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;

import org.springframework.beans.factory.annotation.Autowired;

public class UniqueLoginValidator implements 
ConstraintValidator<UniqueLogin, String> {

    @Autowired
    private UserRepository userRepository;

    public void initialize(UniqueLogin constraint) {
    }

    @Override
    public boolean isValid(String login, ConstraintValidatorContext context) 
    {   
        System.out.println("in UniqueLoginValidator: isValid");
        System.out.println(login);
        System.out.println(userRepository.toString());
        System.out.println(userRepository.findByLogin(login));
        return !userRepository.findByLogin(login).isPresent();
    }

}

BaseRepository ：

package app.user;

import java.util.Optional;

import org.springframework.data.repository.query.Param;
import org.springframework.stereotype.Repository;

import app.BaseRepository;

@Repository
public interface UserRepository extends BaseRepository<User, Long>{

    Optional<User> findByLogin(@Param("login")String login);
}

2 个答案:

答案 0 :(得分：0)

看起来，UniqueLoginValidator类并不是由Spring处理的，因为它没有@Service注释。这很可能就是为什么userRepository变量没有被初始化。

答案 1 :(得分：0)

虽然您的验证器因JSR-303而被选中进行ConstraintValidator验证，但它并未初始化为Spring bean。尝试使用Validator对@Component进行注释，以便在组件扫描阶段将其选中。

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