使用Hibernate在Spring应用程序中向postgresql添加记录时出现NullPointerException

Question

我正在编写一个Spring应用程序，我正在尝试与PostgreSQL数据库中的表进行交互。我在运行应用程序时使用注释来创建表。我遇到的NullPointerException是在我尝试向数据库添加新记录时出现的。

以下是我正在使用的相关代码和配置：

Person.java：

@Entity
@Table(name = "users")
public class Person implements Serializable {

@Id
@GeneratedValue
@Column(name = "id")
private int id;

@Column(name = "firstname")
private String firstName;

@Column(name = "lastname")
private String lastName;

@Column(name = "gender")
private String gender;

@Column(name = "randomanswer")
private String randomAnswer;


public int getId(){
    return id;
}

public void setId(int id){
    this.id = id;
}

public String getFirstName(){
    return firstName;
 }

public void setFirstName(String fName){
    this.firstName = fName;
}

public String getLastName(){
    return lastName;
}

public void setLastName(String lName){
    this.lastName = lName;
}

public String getGender(){
    return gender;
}

public void setGender(String myGender){
    this.gender = myGender;
}

public String getRandomAnswer(){
    return randomAnswer;
}

public void setRandomAnswer(String myRandomAnswer){
    this.randomAnswer = myRandomAnswer;
}

PersonService.java：

public interface PersonService {

    public void addPerson(Person person);
    public List<Person> getPerson();
}

PersonServiceImpl.java：

public class PersonServiceImpl implements PersonService {

     @Autowired
     PersonDao personDao;

    public void setPersonDao(PersonDao personDao) {
        this.personDao = personDao;
    }

    @Override
    public void addPerson(Person person) {
        personDao.addPerson(person);
    }

    @Override
    public List<Person> getPerson() {
        return personDao.getPerson();
    }

}

PersonDao.java：

public interface PersonDao {

    public void addPerson(Person person);
    public List<Person> getPerson();

}

PersonDaoImpl.java：

public class PersonDaoImpl implements PersonDao {
    @Autowired
    private SessionFactory sessionFactory;

    public void setSessionFactory(SessionFactory sessionFactory) {
        this.sessionFactory = sessionFactory;

    }

    @Override
    @Transactional
    public void addPerson(Person person){
        sessionFactory.getCurrentSession().save(person);
    }

    @Override
    @Transactional
    public List<Person> getPerson() {
        return (List<Person>) sessionFactory.getCurrentSession().createCriteria(Person.class).list();
    }

}

MVC-调度-servlet.xml中

<?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:mvc="http://www.springframework.org/schema/mvc"
       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-3.2.xsd
       http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd
       http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd">

    <context:component-scan base-package="com.x" />

    <mvc:annotation-driven />
    <tx:annotation-driven />
    <bean
            class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix">
            <value>/WEB-INF/pages/</value>
        </property>
        <property name="suffix">
            <value>.jsp</value>
        </property>
    </bean>
    <bean id='personService' class='com.x.y.examples.biz.PersonServiceImpl'>
        <property name="personDao" ref="personDao"></property>
    </bean>

   <bean id="personDao" class="com.x.y.examples.biz.PersonDaoImpl">
       <property name="sessionFactory" ref="sessionFactory"/>
   </bean>

    <bean id="dataSource" class="org.postgresql.jdbc2.optional.PoolingDataSource">
        <property name="databaseName" value="mydb"/>
        <property name="serverName" value="localhost"/>
        <property name="user" value="postgres"/>
        <property name="password" value="Adidas1234"/>
        <property name="maxConnections" value="10"/>
    </bean>

    <bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="annotatedClasses">
            <list>
                <value>com.x.y.examples.biz.Person</value>
            </list>
        </property>
        <property name="hibernateProperties">
            <props>
                <prop key="dialect">org.hibernate.dialect.PostgresPlusDialect</prop>
                <prop key="hibernate.show_sql">false</prop>
                <prop key="hibernate.format_sql">true</prop>
                <prop key="hibernate.hbm2ddl.auto">validate</prop>
                <prop key="hibernate.connection.release_mode">on_close</prop>
            </props>
        </property>
    </bean>

    <bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
        <property name="sessionFactory" ref="sessionFactory" />
    </bean>
</beans>

这是堆栈跟踪：

HTTP Status 500 - Request processing failed; nested exception is java.lang.NullPointerException

type Exception report

message Request processing failed; nested exception is java.lang.NullPointerException

description The server encountered an internal error that prevented it from fulfilling this request.

exception

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:948)
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:838)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:118)
    org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:154)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:150)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.authentication.ui.DefaultLoginPageGeneratingFilter.doFilter(DefaultLoginPageGeneratingFilter.java:155)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:199)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:110)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:50)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192)
    org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160)
    org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:343)
    org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:260)

root cause

java.lang.NullPointerException
    org.postgresql.ds.jdbc23.AbstractJdbc23PooledConnection$StatementHandler.invoke(AbstractJdbc23PooledConnection.java:427)
    $Proxy36.hashCode(Unknown Source)
    java.util.HashMap.get(HashMap.java:317)
    org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.release(JdbcCoordinatorImpl.java:373)
    org.hibernate.engine.jdbc.batch.internal.AbstractBatchImpl.releaseStatements(AbstractBatchImpl.java:171)
    org.hibernate.engine.jdbc.batch.internal.NonBatchingBatch.addToBatch(NonBatchingBatch.java:73)
    org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3079)
    org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3521)
    org.hibernate.action.internal.EntityInsertAction.execute(EntityInsertAction.java:88)
    org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:395)
    org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:387)
    org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:303)
    org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:349)
    org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:56)
    org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1159)
    org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:404)
    org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.beforeTransactionCommit(JdbcTransaction.java:101)
    org.hibernate.engine.transaction.spi.AbstractTransactionImpl.commit(AbstractTransactionImpl.java:175)
    org.springframework.orm.hibernate4.HibernateTransactionManager.doCommit(HibernateTransactionManager.java:554)
    org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:755)
    org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:724)
    org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:475)
    org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:270)
    org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:94)
    org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
    $Proxy34.addPerson(Unknown Source)
    com.nexusalpha.jad.examples.biz.PersonServiceImpl.addPerson(PersonServiceImpl.java:25)
    com.nexusalpha.jad.examples.mvc.GreetingController.saveIncident(GreetingController.java:50)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    java.lang.reflect.Method.invoke(Method.java:601)
    org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:219)
    org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
    org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:686)
    org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:925)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936)
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:838)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:118)
    org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:154)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:150)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.authentication.ui.DefaultLoginPageGeneratingFilter.doFilter(DefaultLoginPageGeneratingFilter.java:155)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:199)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:110)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:50)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192)
    org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160)
    org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:343)
    org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:260)

note The full stack trace of the root cause is available in the Apache Tomcat/7.0.37 logs.
Apache Tomcat/7.0.37

当我调试应用程序时，我检查了Person类的实例，看看对象或它的任何属性是否为null，但是那个意义上的所有内容似乎都没问题。 我已经尝试恢复到Hibernate 3并在PersonDaoImpl类中扩展HibernateDaoSupport但这不起作用。

Answer 1

尝试用此

替换您的数据源bean

<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
    <property name="driverClassName" value="org.postgresql.Driver"/>
    <property name="url" value="jdbc:postgresql://localhost:5432/mydb"/>
    <property name="username" value="postgres"/>
    <property name="password" value="Adidas1234"/>
</bean>