我正在使用GenricHibernateDAO，它会自动发送一个sessionfactory，当我通过控制器调用save（user）方法时，它会一直设置为null，它会给我一个空指针异常。
package com.hdo.dao;
public class GenericHibernateDAO<T> implements GenericDAO<T> {
@Autowired
private SessionFactory sessionFactory;
public void setSessionFactory(SessionFactory sessionFactory) {
this.sessionFactory = sessionFactory;
}
@Override
@Transactional
public void save(T t) {
// TODO Auto-generated method stub
sessionFactory.getCurrentSession().save(t);
}
}
UserDAO：
@Repository
public class UserDAO extends GenericHibernateDAO<User> {
public UserDAO() {
super(User.class);
}
public void createUser(User user) {
save(user);
}
}
控制器：
@Controller
public class BasicController {
Logger _LOG = Logger.getLogger(BasicController.class);
@RequestMapping("/")
public ModelAndView home() {
return new ModelAndView("index");
}
@RequestMapping("/userHome")
public ModelAndView goHome(@ModelAttribute("user") User user, Map<String, Object> map, HttpServletRequest request) {
if (null != user) {
//userForm.get
int noOfBreeds = Integer.parseInt(user.getNoOfBreeds());
for (int i = 0; i < noOfBreeds; i++) {
Pet pet = new Pet();
String dogName = request.getParameter("dogName"+i);
String breed = request.getParameter("breed"+i);
pet.setPetName(dogName);
pet.setPetType(breed);
user.addPet(pet);
}
new UserDAO().save(user);
}
return new ModelAndView("userHome");
}
}
pom.xml（properties）
spring.version : 3.2.2.RELEASE
jdk.version : 1.7
hibernate.version : 4.2.0.Final
mysql.connector.version : 5.1.21
tomcat.version : 7.0.33
cglib : 2.2.2
jstl : 1.2
commons-dbcp : 1.4
javax.servlet : 3.0.1
弹簧servlet.xml中
<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:mvc="http://www.springframework.org/schema/mvc"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd">
<context:component-scan base-package="com.hdo" />
<mvc:annotation-driven />
<bean id="messageSource"
class="org.springframework.context.support.ReloadableResourceBundleMessageSource">
<property name="basename" value="classpath:i18n/messages" />
<property name="defaultEncoding" value="UTF-8" />
</bean>
<bean id="localeChangeInterceptor"
class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor">
<property name="paramName" value="lang" />
</bean>
<bean id="localeResolver"
class="org.springframework.web.servlet.i18n.CookieLocaleResolver">
<property name="defaultLocale" value="en" />
</bean>
<bean
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/views/" />
<property name="suffix" value=".jsp" />
</bean>
</beans>
application-context.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:mvc="http://www.springframework.org/schema/mvc"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd">
<context:annotation-config></context:annotation-config>
<context:property-placeholder location="classpath:jdbc.properties"/>
<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName">
<value>${jdbc.driverClassName}</value>
</property>
<property name="url">
<value>${jdbc.databaseurl}</value>
</property>
<property name="username">
<value>${jdbc.username}</value>
</property>
<property name="password">
<value>${jdbc.password}</value>
</property>
</bean>
<bean id="sessionFactory"
class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="packagesToScan" value="com.hdo.model" /> <!-- assuming that is the package with your hibernate entities -->
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">${jdbc.dialect}</prop>
<prop key="hibernate.show_sql">${jdbc.showSql}</prop>
</props>
</property>
</bean>
<tx:annotation-driven transaction-manager="transactionManager"/>
<bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory"/>
</bean>
</beans>
Web.xml：
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/application-context.xml, /WEB-INF/spring-servlet.xml</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<servlet>
<servlet-name>spring</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value></param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>spring</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
日志在这里：
00:06:06,297 DEBUG DefaultIdentifierGeneratorFactory:93 - Registering IdentifierGenerator strategy [enhanced-table] -> [org.hibernate.id.enhanced.TableGenerator]
00:06:06,304 INFO Configuration:1969 - HHH000044: Configuring from URL: file:/home/hanu/tools/tomcat7maven_hpo/webapps/hpo/WEB-INF/classes/hibernate.cfg.xml
00:06:06,357 DEBUG DTDEntityResolver:68 - Trying to resolve system-id [http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd]
00:06:06,365 DEBUG DTDEntityResolver:70 - Recognized hibernate namespace; attempting to resolve on classpath under org/hibernate/
00:06:06,367 DEBUG DTDEntityResolver:107 - Located [http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd] in classpath
00:06:06,400 DEBUG Configuration:2134 - Session-factory config [null] named class [com.hdo.model.User] for mapping
00:06:06,417 INFO Configuration:2074 - HHH000041: Configured SessionFactory: null
00:06:06,715 DEBUG SimpleValueBinder:331 - building SimpleValue for userName
00:06:06,716 DEBUG PropertyBinder:260 - Building property userName
00:06:06,719 DEBUG SimpleValueBinder:369 - Setting SimpleValue typeName for id
00:06:06,720 DEBUG SimpleValueBinder:369 - Setting SimpleValue typeName for confirmPassword
00:06:06,720 DEBUG SimpleValueBinder:369 - Setting SimpleValue typeName for country
00:06:06,720 DEBUG SimpleValueBinder:369 - Setting SimpleValue typeName for email
00:06:06,721 DEBUG SimpleValueBinder:369 - Setting SimpleValue typeName for location
00:06:06,721 DEBUG SimpleValueBinder:369 - Setting SimpleValue typeName for noOfBreeds
00:06:06,722 DEBUG SimpleValueBinder:369 - Setting SimpleValue typeName for password
00:06:06,722 DEBUG SimpleValueBinder:369 - Setting SimpleValue typeName for postCode
00:06:06,723 DEBUG SimpleValueBinder:369 - Setting SimpleValue typeName for state
00:06:06,723 DEBUG SimpleValueBinder:369 - Setting SimpleValue typeName for userName
00:06:06,725 DEBUG Configuration:1406 - Processing fk mappings (*ToOne and JoinedSubclass)
00:06:06,728 DEBUG Configuration:1585 - Processing extends queue
00:06:06,729 DEBUG Configuration:1643 - Processing extends queue
00:06:06,729 DEBUG Configuration:1588 - Processing collection mappings
00:06:06,730 DEBUG Configuration:1598 - Processing native query and ResultSetMapping mappings
00:06:06,730 DEBUG Configuration:1606 - Processing association property references
00:06:06,730 DEBUG Configuration:1628 - Creating tables' unique integer identifiers
00:06:06,731 DEBUG Configuration:1629 - Processing foreign key constraints
00:06:07,128 DEBUG JdbcServicesImpl:121 - Database ->
name : MySQL
version : 5.5.29-0ubuntu0.12.10.1
major : 5
minor : 5
00:06:07,129 DEBUG JdbcServicesImpl:127 - Driver ->
name : MySQL-AB JDBC Driver
version : mysql-connector-java-5.1.21 ( Revision: ${bzr.revision-id} )
major : 5
minor : 1
00:06:07,130 DEBUG JdbcServicesImpl:133 - JDBC version : 4.0
00:06:07,169 INFO Dialect:128 - HHH000400: Using dialect: org.hibernate.dialect.MySQLDialect
00:06:07,216 DEBUG SettingsFactory:114 - Automatic flush during beforeCompletion(): disabled
00:06:07,217 DEBUG SettingsFactory:120 - Automatic session close at end of transaction: disabled
00:06:07,217 DEBUG SettingsFactory:131 - JDBC batch size: 15
00:06:07,218 DEBUG SettingsFactory:137 - JDBC batch updates for versioned data: disabled
00:06:07,218 DEBUG SettingsFactory:147 - Scrollable result sets: enabled
00:06:07,219 DEBUG SettingsFactory:153 - Wrap result sets: disabled
00:06:07,219 DEBUG SettingsFactory:159 - JDBC3 getGeneratedKeys(): enabled
00:06:07,219 DEBUG SettingsFactory:171 - multi-tenancy strategy : NONE
00:06:07,220 DEBUG SettingsFactory:177 - Connection release mode: auto
00:06:07,220 INFO TransactionFactoryInitiator:68 - HHH000399: Using default transaction strategy (direct JDBC transactions)
00:06:07,226 DEBUG SettingsFactory:199 - Using BatchFetchStyle : LEGACY
00:06:07,227 DEBUG SettingsFactory:218 - Maximum outer join fetch depth: 2
00:06:07,227 DEBUG SettingsFactory:224 - Default batch fetch size: 1
00:06:07,228 DEBUG SettingsFactory:230 - Generate SQL with comments: disabled
00:06:07,228 DEBUG SettingsFactory:236 - Order SQL updates by primary key: disabled
00:06:07,228 DEBUG SettingsFactory:242 - Order SQL inserts for batching: disabled
00:06:07,229 DEBUG SettingsFactory:250 - Default null ordering: none
00:06:07,230 DEBUG SettingsFactory:541 - Query translator: org.hibernate.hql.internal.ast.ASTQueryTranslatorFactory
00:06:07,234 INFO ASTQueryTranslatorFactory:48 - HHH000397: Using ASTQueryTranslatorFactory
00:06:07,235 DEBUG SettingsFactory:260 - Query language substitutions: {}
00:06:07,235 DEBUG SettingsFactory:266 - JPA-QL strict compliance: disabled
00:06:07,236 DEBUG SettingsFactory:274 - Second-level cache: enabled
00:06:07,236 DEBUG SettingsFactory:280 - Query cache: disabled
00:06:07,842 DEBUG BeanNameUrlHandlerMapping:86 - Rejected bean name 'org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping': no URL paths identified
00:06:07,843 DEBUG BeanNameUrlHandlerMapping:86 - Rejected bean name 'org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter': no URL paths identified
00:06:07,843 DEBUG BeanNameUrlHandlerMapping:86 - Rejected bean name 'org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter': no URL paths identified
00:06:07,843 DEBUG BeanNameUrlHandlerMapping:86 - Rejected bean name 'org.springframework.beans.factory.config.PropertyPlaceholderConfigurer#0': no URL paths identified
00:06:07,843 DEBUG BeanNameUrlHandlerMapping:86 - Rejected bean name 'messageSource': no URL paths identified
00:06:07,843 DEBUG BeanNameUrlHandlerMapping:86 - Rejected bean name 'localeChangeInterceptor': no URL paths identified
00:06:07,844 DEBUG BeanNameUrlHandlerMapping:86 - Rejected bean name 'localeResolver': no URL paths identified
00:06:07,844 DEBUG BeanNameUrlHandlerMapping:86 - Rejected bean name 'org.springframework.web.servlet.view.InternalResourceViewResolver#0': no URL paths identified
00:06:07,844 DEBUG BeanNameUrlHandlerMapping:86 - Rejected bean name 'dataSource': no URL paths identified
00:06:07,844 DEBUG BeanNameUrlHandlerMapping:86 - Rejected bean name 'sessionFactory': no URL paths identified
00:06:07,845 DEBUG BeanNameUrlHandlerMapping:86 - Rejected bean name 'genericHibernateDAO': no URL paths identified
00:06:07,845 DEBUG BeanNameUrlHandlerMapping:86 - Rejected bean name 'org.springframework.context.annotation.ConfigurationClassPostProcessor.importAwareProcessor': no URL paths identified
00:06:07,845 DEBUG BeanNameUrlHandlerMapping:86 - Rejected bean name 'environment': no URL paths identified
00:06:07,845 DEBUG BeanNameUrlHandlerMapping:86 - Rejected bean name 'systemProperties': no URL paths identified
00:06:07,846 DEBUG BeanNameUrlHandlerMapping:86 - Rejected bean name 'systemEnvironment': no URL paths identified
00:06:07,846 DEBUG BeanNameUrlHandlerMapping:86 - Rejected bean name 'servletConfig': no URL paths identified
00:06:07,846 DEBUG BeanNameUrlHandlerMapping:86 - Rejected bean name 'org.springframework.context.annotation.ConfigurationClassPostProcessor.importRegistry': no URL
00:06:07,886 DEBUG DefaultListableBeanFactory:215 - Creating shared instance of singleton bean 'org.springframework.web.servlet.view.InternalResourceViewResolver#0'
00:06:07,886 DEBUG DefaultListableBeanFactory:435 - Creating instance of bean 'org.springframework.web.servlet.view.InternalResourceViewResolver#0'
00:06:07,902 DEBUG DefaultListableBeanFactory:509 - Eagerly caching bean 'org.springframework.web.servlet.view.InternalResourceViewResolver#0' to allow for resolving potential circular references
00:06:07,926 DEBUG DefaultListableBeanFactory:463 - Finished creating instance of bean 'org.springframework.web.servlet.view.InternalResourceViewResolver#0'
00:06:07,927 DEBUG DefaultListableBeanFactory:246 - Returning cached instance of singleton bean 'dataSource'
00:06:07,927 DEBUG DefaultListableBeanFactory:246 - Returning cached instance of singleton bean 'sessionFactory'
00:06:07,927 DEBUG DefaultListableBeanFactory:215 - Creating shared instance of singleton bean 'genericHibernateDAO'
00:06:07,928 DEBUG DefaultListableBeanFactory:435 - Creating instance of bean 'genericHibernateDAO'
00:06:07,930 DEBUG InjectionMetadata:71 - Registered injected element on class [com.hdo.dao.GenericHibernateDAO]: AutowiredFieldElement for private org.hibernate.SessionFactory com.hdo.dao.GenericHibernateDAO.sessionFactory
00:06:07,931 DEBUG DefaultListableBeanFactory:509 - Eagerly caching bean 'genericHibernateDAO' to allow for resolving potential circular references
00:06:07,935 DEBUG InjectionMetadata:85 - Processing injected method of bean 'genericHibernateDAO': AutowiredFieldElement for private org.hibernate.SessionFactory com.hdo.dao.GenericHibernateDAO.sessionFactory
00:06:07,935 DEBUG DefaultListableBeanFactory:246 - Returning cached instance of singleton bean 'sessionFactory'
00:06:07,936 DEBUG AutowiredAnnotationBeanPostProcessor:433 - Autowiring by type from bean name 'genericHibernateDAO' to bean named 'sessionFactory'
00:06:07,936 DEBUG DefaultListableBeanFactory:246 - Returning cached instance of singleton bean 'sessionFactory'
00:06:07,937 DEBUG DefaultListableBeanFactory:463 - Finished creating instance of bean 'genericHibernateDAO'
00:06:07,937 DEBUG DefaultListableBeanFactory:246 - Returning cached instance of singleton bean 'org.springframework.context.annotation.ConfigurationClassPostProcessor.importAwareProcessor'
00:06:07,937 DEBUG XmlWebApplicationContext:858 - Unable to locate LifecycleProcessor with name 'lifecycleProcessor': using default [org.springframework.context.support.DefaultLifecycleProcessor@2f3fc03c]
00:06:07,938 DEBUG DefaultListableBeanFactory:246 - Returning cached instance of singleton bean 'lifecycleProcessor'
00:36:51,774 DEBUG DispatcherServlet:823 - DispatcherServlet with name 'spring' processing POST request for [/hpo/userHome.do]
11:00:56,266 DEBUG ResponseStatusExceptionResolver:132 - Resolving exception from handler [public org.springframework.web.servlet.ModelAndView com.hdo.spring.controller.BasicController.goHome(com.hdo.model.User,java.util.Map<java.lang.String, java.lang.Object>,javax.servlet.http.HttpServletRequest)]: java.lang.NullPointerException
11:00:56,267 DEBUG DefaultHandlerExceptionResolver:132 - Resolving exception from handler [public org.springframework.web.servlet.ModelAndView com.hdo.spring.controller.BasicController.goHome(com.hdo.model.User,java.util.Map<java.lang.String, java.lang.Object>,javax.servlet.http.HttpServletRequest)]: java.lang.NullPointerException
11:00:56,269 DEBUG DispatcherServlet:959 - Could not complete request
java.lang.NullPointerException
at com.hdo.dao.GenericHibernateDAO.getCurrentSession(GenericHibernateDAO.java:27)
at com.hdo.dao.GenericHibernateDAO.save(GenericHibernateDAO.java:33)
at com.hdo.spring.controller.BasicController.goHome(BasicController.java:59)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:219)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:686)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:925)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936)
我对spring mvc完全不熟悉我想我在这里处理多个问题，我将sessionFactory设置为[null]并将Rejected bean名称设置为“sessionFactory”。我试过在spring mvc3.2.2和hibernate4中使用所有最新的jar。我无法弄清楚这个问题是什么，所以请帮忙吗？
答案 0 :(得分：10)
判断你的LocalSessionFactoryBean你可能混合了一些Hibernate 3和4的教程（它们的配置方式略有不同）。
<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="packagesToScan" value="com.hdo.model" /> <!-- assuming that is the package with your hibernate entities -->
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">${jdbc.dialect}</prop>
<prop key="hibernate.show_sql">${jdbc.showSql}</prop>
</props>
</property>
</bean>
我也缺少事务管理配置：
<tx:annotation-driven />
另一个错误是手动定义DAO bean，如果它已被component-scan选中：
<context:component-scan base-package="com.hdo.dao" />
最后 - 这种配置通常放在根Web应用程序上下文中。 Servlet应用程序上下文用于处理程序（控制器），处理程序映射，处理程序适配器和处理程序拦截器（如LocaleChangeInterceptor）。
更新您的更新代码中存在多个错误。让我们逐一介绍它们：
web.xml中的根网络应用上下文加载servlet应用上下文。spring-servlet.xml，然后删除弹簧servlet的空init-param（spring-servlet.xml是它将加载的默认名称。<context:component-scan base-package="com.hdo.controller" />，并将另一个组件扫描添加到根应用程序上下文<context:component-scan base-package="com.hdo.dao" />（您还可以删除注释-config 声明，因为组件扫描会自动生成。createUser中的UserDAO方法并直接从控制器调用save方法。UserDAO bean。使用Spring等IoC容器时，需要让它注入依赖项。new UserDAO行并添加@Autowire UserDAO userDao;属性。 Spring会为你注入你的DAO实例。此类实例将初始化其依赖项（例如sessionFactory。