package baigu.web;import java.util.List;import org.hibernate.Session;import baigu.HibernateSessionFactory;
import baigu.dao.GoodsDao;
import baigu.dao.impl.GoodsDaoImpl;
import baigu.model.Goods;import com.opensymphony.xwork2.ActionSupport;/**
 * 测试
 * @author lzm
 *
 */
public class MyTestAction extends ActionSupport {
//测试
GoodsDao dao = new GoodsDaoImpl();
private Goods good; @Override
public String execute() throws Exception {
    Session session = HibernateSessionFactory.getSession();
    List<Goods> alist = null;
alist = session.createQuery("from Goods").list();
good = alist.get(0);
   //返回成功
   return SUCCESS;
} public Goods getGood() {
return good;
} public void setGood(Goods good) {
this.good = good;
}

}错误如下:
exception javax.servlet.ServletException: java.lang.NullPointerException
org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:515)
org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:422)
root cause java.lang.NullPointerException
baigu.web.MyTestAction.execute(MyTestAction.java:37)
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)
com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:404)
com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:267)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:229)
com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:221)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:150)
org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:48)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86)数据库表明明有记录,但session.createQuery却返回空值??
如何解决?