严重: Servlet.service() for servlet action threw exception
java.lang.NullPointerException
at com.test.struts.action.G3OrderAction.findAll(G3OrderAction.java:58)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:270)
at org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:187)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
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.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
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:104)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:261)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:581)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Unknown Source)

解决方案 »

  1.   

    空指针,光看异常不知道什么原因,看看你的方法.findAll是不是有问题
      

  2.   


    java.lang.NullPointerException
    at com.test.struts.action.G3OrderAction.findAll(G3OrderAction.java:58)
      

  3.   

    at com.test.struts.action.G3OrderAction.findAll(G3OrderAction.java:58)
      

  4.   

    at com.test.struts.action.G3OrderAction.findAll(G3OrderAction.java:58)
      

  5.   


    这是action类
    /*
     * Generated by MyEclipse Struts
     * Template path: templates/java/JavaClass.vtl
     */
    package com.test.struts.action;import java.util.List;
    import java.lang.*;import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import org.apache.struts.action.ActionForm;
    import org.apache.struts.action.ActionForward;
    import org.apache.struts.action.ActionMapping;
    import org.apache.struts.actions.DispatchAction;import com.test.biz.G3OrderBiz;
    import com.test.struts.form.G3OrderForm;/** 
     * MyEclipse Struts
     * Creation date: 07-14-2010
     * 
     * XDoclet definition:
     * @struts.action path="/g3Order" name="g3OrderForm" parameter="param" scope="request" validate="true"
     * @struts.action-forward name="success" path="/list.jsp"
     * @struts.action-forward name="fail" path="/index.jsp"
     */
    public class G3OrderAction extends DispatchAction {
    /*
     * Generated Methods
     */ private G3OrderBiz orderBiz;
    public G3OrderBiz getOrderBiz() {
    return orderBiz;
    } public void setOrderBiz(G3OrderBiz orderBiz) {
    this.orderBiz = orderBiz;
    } /** 
     * Method execute
     * @param mapping
     * @param form
     * @param request
     * @param response
     * @return ActionForward
     */

    public ActionForward findAll(ActionMapping mapping, ActionForm form,
    HttpServletRequest request, HttpServletResponse response) {
    G3OrderForm g3OrderForm = (G3OrderForm) form;// TODO Auto-generated method stub
    String result=request.getParameter("username");
    if(result.equals("admin"))
    {
    List list=orderBiz.findAll();
    request.setAttribute("resultList", list);
    return mapping.findForward("success");
    }
    return mapping.findForward("fail");
    }

    public ActionForward delete(ActionMapping mapping, ActionForm form,
    HttpServletRequest request, HttpServletResponse response) {
    G3OrderForm g3OrderForm = (G3OrderForm) form;// TODO Auto-generated method stub
    return null;
    } }
    BIZ类:
    package com.test.biz;import java.util.List;import com.test.dao.G3OrderDao;
    import com.test.entity.G3Order;public class G3OrderBiz { private G3OrderDao orderDao;
    public List findAll()
    {
    return orderDao.loadAll(G3Order.class);
    }
    public G3OrderDao getOrderDao() {
    return orderDao;
    }
    public void setOrderDao(G3OrderDao orderDao) {
    this.orderDao = orderDao;
    }
    }
    DAO类:
    package com.test.dao;import java.util.List;import org.springframework.orm.hibernate3.support.HibernateDaoSupport;public class G3OrderDao extends HibernateDaoSupport  { public List loadAll(final Class clazz) {
    return getHibernateTemplate().loadAll(clazz);
    }
    }
      

  6.   


    G3OrderAction.findAll(G3OrderAction.java:58)String result=request.getParameter("username");
    if(result.equals("admin"))//看看result是否为null
    {
    List list=orderBiz.findAll();
    orderBiz是否成功被spring注入
    orderDao也是否成功注入
      

  7.   

    result   不为空   orderBiz和orderDao注入了
      

  8.   

    public ActionForward findAll(ActionMapping mapping, ActionForm form,
    HttpServletRequest request, HttpServletResponse response) {
    G3OrderForm g3OrderForm = (G3OrderForm) form;// TODO Auto-generated method stub
    String result=request.getParameter("username");
    if(result.equals("admin"))
    {
    List list=orderBiz.findAll();
    request.setAttribute("resultList", list);
    return mapping.findForward("success");
    }
    return mapping.findForward("fail");
    }public ActionForward delete(ActionMapping mapping, ActionForm form,
    HttpServletRequest request, HttpServletResponse response) {
    G3OrderForm g3OrderForm = (G3OrderForm) form;// TODO Auto-generated method stub
    return null;
    }}
    G3OrderForm g3OrderForm = (G3OrderForm) form;// TODO Auto-generated method stub
    set方法呢????
      

  9.   

    楼主,设断点在Action的58行,然后调试,这种问题一般10分钟左右可以定位
      

  10.   

       问题是就不进biz的方法    设断点的时候就停了   网页直接出错误提示了~ 
      

  11.   

    你注意看你那个username和页面是不是同一个  是不是写错了
      

  12.   

    你调用了G3OrderAction 的findAll方法
    这个G3OrderAction继承于DispatchAction在配置的时候加过parameter="method"吗?
    <action path="/G3OrderAction" scope="request"
    type="org.springframework.web.struts.DelegatingActionProxy" parameter="method">
      

  13.   

      没加过   加的是parameter="param"