李兴华视频的MLDN项目。用SSH整合时出现了问题。

Question

我根据视频中的一步一步的做的，可是在做到注册页面时。当点提交时就出项如下错误。
HTTP Status 500
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userdaoimpl' defined in ServletContext resource [/WEB-INF/classes/applicationContext.xml]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.lxh.myznt.dao.impl.UserDAOImpl]: Constructor threw exception; nested exception is java.lang.NullPointerException
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:403)
org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:233)
org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:145)
org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:283)
org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:313)
org.springframework.web.context.support.AbstractRefreshableWebApplicationContext.refresh(AbstractRefreshableWebApplicationContext.java:139)
org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:252)
org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:190)
org.springframework.web.context.ContextLoaderServlet.init(ContextLoaderServlet.java:83)
javax.servlet.GenericServlet.init(GenericServlet.java:212)
org.apache.catalina.startup.Catalina.start(Catalina.java:552)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:295)
org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:433)那位高手帮我解决一下啊

Answer 1

com.lxh.myznt.dao.impl.UserDAOImpl
检查这个类的构造函数，是不是传了null的参数。

Answer 2

我想也是这里传来一个NULL参数，我看了一下源代码，这个参数应该是sessionFactory,可是我觉得 我的sessionFactoryme没有配置错呀。applicationContext.xml如下：
<beans>
<bean id="dataSource"
class="org.springframework.jndi.JndiObjectFactoryBean"
destroy-method="close">
<property name="jndiName">
<value>java:comp/env/jdbc/mldn</value>
</property>
</bean>

<bean id="hibernateInterceptor"
class="org.springframework.orm.hibernate3.HibernateInterceptor">
<property name="sessionFactory">
<ref bean="sessionFactory" />
</property>
</bean> 

<bean id="sessionFactory"
class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
<property name="dataSource">
<ref bean="dataSource" />
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">
org.hibernate.dialect.MySQLDialect
</prop>

<prop key="hibernate.connection.autocommit">true</prop>

<prop key="hibernate.show_sql">true</prop>
</props>
</property>
<property name="mappingResources">
<list>
<value>com/lxh/myznt/vo/User.hbm.xml</value></list>
</property></bean>

<bean id="hibernateTemplate" class="org.springframework.orm.hibernate3.HibernateTemplate">
<property name="sessionFactory" ref="sessionFactory">

</property>
</bean>
    <bean id="userdao" class="com.lxh.myznt.dao.UserDAO"
abstract="true">
</bean>
<bean id="userdaoimpl" class="com.lxh.myznt.dao.impl.UserDAOImpl"
parent="userdao">
<property name="hibernateTemplate" ref="hibernateTemplate">
</property>
</bean>
<bean name="/jsp/user" class="com.lxh.myznt.struts.action.UserAction">
<property name="userdao">
<ref bean="userdaoimpl"/>
</property>
</bean>
</beans>请高手指教！！谢谢

Answer 3

再附上UserDAOImpl的源代码package com.lxh.myznt.dao.impl;
import net.sf.hibernate.SessionFactory;
import org.springframework.orm.hibernate3.HibernateTemplate;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;import com.lxh.myznt.dao.UserDAO;
import com.lxh.myznt.vo.User;public class UserDAOImpl extends HibernateDaoSupport implements UserDAO {

private SessionFactory sessionFactory;

public void register(User user)throws Exception{
super.getSession().save(user);
}
}

Answer 4

求求各位高手了，我完全是自学的SSH。我完全按照李兴华这个视频做的，可就是有错，我已经整
了几天了，可是还没搞定。

Answer 5

public class UserDAOImpl extends HibernateDaoSupport implements UserDAO {private SessionFactory sessionFactory;//为什么要有这个public void register(User user)throws Exception{
super.getSession().save(user);
}
}

Answer 6

再附上WEB.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.4"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee   http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

<filter>
<filter-name>encoding</filter-name>
<filter-class>com.lxh.myznt.filter.EncodingFilter</filter-class>
<init-param>
<param-name>charset</param-name>
<param-value>gbk</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>encoding</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<filter>
<filter-name>opensession</filter-name>
<filter-class>
org.springframework.orm.hibernate3.support.OpenSessionInViewFilter
</filter-class>
</filter>
<filter-mapping>
<filter-name>opensession</filter-name>
<url-pattern>*.do</url-pattern>
</filter-mapping>
  <context-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>
          /WEB-INF/classes/applicationContext.xml
      </param-value>
  </context-param>
  <servlet>
      <servlet-name>contextLoader</servlet-name>
      <servlet-class>
          org.springframework.web.context.ContextLoaderServlet
      </servlet-class>
      <load-on-startup>1</load-on-startup>
  </servlet> <servlet>
<servlet-name>action</servlet-name>
<servlet-class>
org.apache.struts.action.ActionServlet
</servlet-class>
<init-param>
<param-name>config</param-name>
<param-value>/WEB-INF/struts-config.xml</param-value>
</init-param>
<init-param>
<param-name>debug</param-name>
<param-value>3</param-value>
</init-param>
<init-param>
<param-name>detail</param-name>
<param-value>3</param-value>
</init-param>
<load-on-startup>0</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>action</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<resource-ref> 
      <description>DB Connection</description> 
      <res-ref-name>jdbc/mldn</res-ref-name> 
      <res-type>javax.sql.DataSource</res-type> 
      <res-auth>Container</res-auth> 
     </resource-ref> 
</web-app>

Answer 7

<beans> 
<bean id="dataSource" 
class="org.springframework.jndi.JndiObjectFactoryBean" 
destroy-method="close"> 
<property name="jndiName"> 
<value>java:comp/env/jdbc/mldn </value> 
</property> 
</bean> <bean id="hibernateInterceptor" 
class="org.springframework.orm.hibernate3.HibernateInterceptor"> 
<property name="sessionFactory"> 
<ref bean="sessionFactory" /> 
</property> 
</bean> <bean id="sessionFactory" 
class="org.springframework.orm.hibernate3.LocalSessionFactoryBean"> 
<property name="dataSource"> 
<ref bean="dataSource" /> 
</property> 
<property name="hibernateProperties"> 
<props> 
<prop key="hibernate.dialect"> 
org.hibernate.dialect.MySQLDialect 
</prop> <prop key="hibernate.connection.autocommit">true </prop> <prop key="hibernate.show_sql">true </prop> 
</props> 
</property> 
<property name="mappingResources"> 
<list> 
<value>com/lxh/myznt/vo/User.hbm.xml </value> </list> 
</property> </bean> <bean id="hibernateTemplate" class="org.springframework.orm.hibernate3.HibernateTemplate"> 
  <property name="sessionFactory" ref="sessionFactory"/> 
</bean> 
<bean id="userdao" class="com.lxh.myznt.dao.UserDAO"  abstract="true"> 
</bean> 
<bean id="userdaoimpl" class="com.lxh.myznt.dao.impl.UserDAOImpl" parent="userdao"> 
<bean id="userdaoimpl" class="com.lxh.myznt.dao.impl.UserDAOImpl">
  <property name="hibernateTemplate" ref="hibernateTemplate"/> 
</bean> 
<bean name="/jsp/user" class="com.lxh.myznt.struts.action.UserAction"> 
  <property name="userdao"> 
    <ref bean="userdaoimpl"/> 
  </property> 
</bean> 
</beans> 
然后public class UserDAOImpl extends HibernateDaoSupport implements UserDAO { 
  private SessionFactory sessionFactory;    //去掉这个
  public void register(User user)throws Exception{ 
    super.getSession().save(user); 
  }
}

Answer 8

<bean id="userdao" class="com.lxh.myznt.dao.UserDAO"  abstract="true"> 
</bean>这个是要删除的