S2SH下空指针问题 求助

S2SH整合 做个登陆搜索系统。一直有个空指针错误 不知道怎么解决 好像是注入的问题 但是不知道问题在哪里package action;
import dao.AccountDAO;
import model.Account;public class LoginAction{
    private Account account;
    private AccountDAO accountDao;    
    public void setAccount(Account account)
    {
        this.account=account;
    }
    public Account getAccount ()
    {
        return account;
    }
    public void setAccountDao(AccountDAO accountDao)
    {
        this.accountDao = accountDao;
    }
    public AccountDAO getAccountDao()
    {
        return this.accountDao;
    }
    
    public String execute() 
    {
        System.out.print(accountDao.toString());
/报错         System.out.print(accountDao.toString()+"name:"+account.getName()+"password:"+account.getPassword());
        if (accountDao.isValid(account.getName(),account.getPassword())==true) return "success";
        else return "fail";
    }
}
在AccountDAO中我自己实现的代码
public boolean isValid(final String name,final String password) {
        Session session=getHibernateTemplate().getSessionFactory().openSession();
        Criteria tmp=session.createCriteria(Account.class);
        List result = tmp.add(Restrictions.eq("name", name))
                         .add(Restrictions.eq("password", password))
                         .list();
        if(result.size()>0) {
            return true;
        } else {
            return false;
        }    
    }
<?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:p="http://www.springframework.org/schema/p"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
    <bean id="dataSource"
        class="org.apache.commons.dbcp.BasicDataSource">
        <property name="driverClassName"
            value="com.mysql.jdbc.Driver">
        </property>
        <property name="url"
            value="jdbc:mysql://localhost:3306/large_experiment">
        </property>
        <property name="username" value="root"></property>
        <property name="password" value="123456"></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>
            </props>
        </property>
        <property name="mappingResources">
            <list>
                <value>model/Person.hbm.xml</value>
                <value>model/Account.hbm.xml</value></list>
        </property></bean>
    <bean id="PersonDAO" class="dao.PersonDAO">
        <property name="sessionFactory">
            <ref bean="sessionFactory" />
        </property>
    </bean>
    <bean id="AccountDAO" class="dao.AccountDAO">
        <property name="sessionFactory">
            <ref bean="sessionFactory" />
        </property>
    </bean>
    <bean id="LoginAction" class="action.LoginAction">
        <property name="accountDao">
            <ref bean="AccountDAO" />
        </property>
    </bean>
</beans>现在我觉得应该是配置文件的注入问题。不知道怎么搞   
而且 我想问个问题 为什么在AccountDAO文件中 取session的那句话也是空指针错误
求助啊 谢谢
异常错误信息：type Exception reportmessage  description The server encountered an internal error () that prevented it from fulfilling this request.exception  java.lang.NullPointerException
action.LoginAction.execute(LoginAction.java:31)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:597)
com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:441)
com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:280)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:243)
com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:165)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:252)
org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:122)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:179)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:94)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:235)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:89)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:130)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:267)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:126)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:138)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:165)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:179)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:176)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)
org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:488)
org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:395)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.13 logs.

解决方案 »

  1.   

    debug一下不就出来了么？
    实例化
      

  2.   

    问题需要一步步解决第一：首先确保数据源能够回去第二：在AccountDAO中写一个方法看是否能够回去到AccountDAO实例，比如
    ClassPathResource resource = new ClassPathResource("applicationContext.xml");
    XmlBeanFactory factory = new XmlBeanFactory(resource);
    BasicDataSource o = (BasicDataSource) factory.getBean("dataSource");第三：在LoginAction中System.out.print一下各个前台参数 看是否能够获取
      

  3.   

    java.lang.NullPointerException
    action.LoginAction.execute(LoginAction.java:31)
      

  4.   

    accountDao   这个是什么？