发新话题
移动帖子 加入精华 加入置顶 加入收藏 关注此帖

请教大家一个spring的问题



请教大家一个spring的问题

我用spring实现一个简单的登陆,但是注入的那个对象报了一个空指针的错误

下面是登陆这一部分的配置文件:(里面的sessionFactory和baseTransProxy正常,在别的地方用到没问题)
<bean id="loginDaoTarget"
class="com.newer.business.web.dao.LoginDao">
<property name="sessionFactory">
<ref bean="sessionFactory"></ref>
</property>
</bean>
<bean id="loginDao" parent="baseTransProxy">
<property name="target" ref="userDaoTarget"></property>
</bean>

action里面的代码:
public class LoginAction extends Action{
private LoginDao loginDao;
public void setLoginDao(LoginDao loginDao) {
this.loginDao = loginDao;
}
public ActionForward execute(ActionMapping mapping, ActionForm loginForm, HttpServletRequest request, HttpServletResponse response) throws Exception {
// TODO Auto-generated method stub
LoginForm lf=(LoginForm)loginForm;
ActionForward f=null;
if(loginDao.checkLogin(lf.getU())){
f=mapping.findForward("ok");
}else{
f=mapping.findForward("fail");
}
return f;
}
}

dao层的代码:
public class LoginDao extends HibernateDaoSupport{

@SuppressWarnings("unchecked")
public boolean checkLogin(UseInfo u){
List<UseInfo> list=this.getHibernateTemplate().find("from UseInfo where uname='"+u.getUname()+"' and upwd='"+u.getUpwd()+"'");
if(list.size()==0){
return false;
}else if(list.size()==1){
return true;
}
return false;
}
}

现在确定路径和名字都没错,但是他报loginDao的空指针错误,请问一下问题可能出在哪里
编辑 回复 快速回复 TOP

Re:请教大家一个spring的问题

仔细看看异常吧,一定有你遗漏的部分。

或者贴上来大家看看!
快乐渡过每一天,减肥坚持每一天
编辑 回复 快速回复 TOP

Re:请教大家一个spring的问题

下面是报错的内容
我加了一个打印loginDao的代码,值为空
loginDao的值为:null
2008-8-18 18:17:15 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet action threw exception
java.lang.NullPointerException
at com.newer.business.web.action.LoginAction.execute(LoginAction.java:29)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:198)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:75)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:263)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:584)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Unknown Source)
编辑 回复 快速回复 TOP
发新话题