自定义对象列表无法在运行时添加对象给出“Nullpointer Exception”

时间：2012-12-06 14:08:21

标签： list jsp nullpointerexception dynamicobject tobjectlist

我在创建一个自定义类型对象列表列表并在该列表中添加一些对象时遇到了一些问题。 我有一个advertise对象列表

public int ajax_GenerateReports(ResourceRequest request, ResourceResponse response) throws Exception {

    log.info("ajax_Generate Reports Enter");

    String strcamp_id =  request.getParameter("CMD");

    log.info("ajax_Generate Reports Enter"+strcamp_id);

    long camp_id = Long.parseLong(strcamp_id);

    log.info("camp_ID:-"+ camp_id);

    int iResult = 1;

    List<campaign_map_adv> camp_map_adv_List = null;

    List<advertise> adv_List = null;

    camp_map_adv_List = campaign_map_advLocalServiceUtil.getAllCamp_Map_Adv_By_campID(camp_id);

    log.info("CAMPIAGN MAP OBJECT : - "+ camp_map_adv_List.get(0));
    log.info("CAMPIAGN MAP OBJECT List Count : - "+ camp_map_adv_List.size());

    if(!camp_map_adv_List.isEmpty()) { //Search For Each Camp entry in camp_map Adv

        for (campaign_map_adv campaign_map_advitem : camp_map_adv_List) {                
            //add each advertise to temporary list file of advertise from camp_map_adv
            advertise temp_ad = advertiseLocalServiceUtil.getadvertise(campaign_map_advitem.getAdvId());

            adv_List.add(temp_ad);
        }

    }
    //          

    ////////////////
    System.setProperty("java.awt.headless", "true");
    System.out.println(java.awt.GraphicsEnvironment.isHeadless());
    System.out.println("IN GENRATE REPORTS ");

    System.out.println("IN GENRATE LIST " +adv_List.size());

    JRBeanCollectionDataSource beanCollectionDataSource = new JRBeanCollectionDataSource(adv_List);

    System.out.println(" bean collection " + beanCollectionDataSource.getRecordCount());

    System.out.println("Test!!");

    JasperPrint jasperPrint = JasperFillManager
            .fillReport(
                    "C:/liferay/tomcat-7.0.27/webapps/eMenuAdvertise-portlet/src_reports/report3.jasper",
                    new HashMap<String, Object>(), beanCollectionDataSource);

    System.out.println(" report path ");
    JasperExportManager.exportReportToHtmlFile(jasperPrint, "c:/liferay/report.html");

    ///////////////

    log.info("ajax_GenerateReports Leave");

    return iResult;
}

从以下一行开始，插入第一个对象后，我的代码出现运行时错误：

advertise temp_ad = advertiseLocalServiceUtil.getadvertise(campaign_map_advitem.getAdvId());

adv_List.add(temp_ad);

所以，如果有人可以指导我......

堆栈追踪： - 

18:32:21,719 INFO  [http-bio-8080-exec-56][RestaurantPortlet:2311] serveResource Start
18:32:21,746 INFO  [http-bio-8080-exec-56][RestaurantPortlet:2322] Resource Id - generate_report
18:32:21,747 INFO  [http-bio-8080-exec-56][RestaurantPortlet:2225] ajax_Generate Reports Enter
18:32:21,747 INFO  [http-bio-8080-exec-56][RestaurantPortlet:2228] ajax_Generate Reports Enter22901
18:32:21,747 INFO  [http-bio-8080-exec-56][RestaurantPortlet:2230] camp_ID:-22901
18:32:21,778 INFO  [http-bio-8080-exec-56][RestaurantPortlet:2237] CAMPIAGN MAP OBJECT : - {id=22902, campaignId=22901, advId=18726, restId=15101, isactive=true, adtypeId=4}
18:32:21,779 INFO  [http-bio-8080-exec-56][RestaurantPortlet:2238] CAMPIAGN MAP OBJECT : - 7
java.lang.NullPointerException
    at emenu.advertise.portlet.RestaurantPortlet.ajax_GenerateReports(RestaurantPortlet.java:2248)
    at emenu.advertise.portlet.RestaurantPortlet.serveResource(RestaurantPortlet.java:2437)
    at com.liferay.portlet.FilterChainImpl.doFilter(FilterChainImpl.java:118)
    at com.liferay.portal.kernel.portlet.PortletFilterUtil.doFilter(PortletFilterUtil.java:71)
    at com.liferay.portal.kernel.servlet.PortletServlet.service(PortletServlet.java:111)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:72)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilter.doFilter(InvokerFilter.java:73)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:684)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:471)
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:402)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:329)
    at com.liferay.portlet.InvokerPortletImpl.invoke(InvokerPortletImpl.java:531)
    at com.liferay.portlet.InvokerPortletImpl.invokeResource(InvokerPortletImpl.java:626)
    at com.liferay.portlet.InvokerPortletImpl.serveResource(InvokerPortletImpl.java:436)
    at com.liferay.portal.action.LayoutAction.processPortletRequest(LayoutAction.java:1075)
    at com.liferay.portal.action.LayoutAction.processLayout(LayoutAction.java:719)
    at com.liferay.portal.action.LayoutAction.execute(LayoutAction.java:249)
    at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
    at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
    at com.liferay.portal.struts.PortalRequestProcessor.process(PortalRequestProcessor.java:176)
    at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
    at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
    at com.liferay.portal.servlet.MainServlet.callParentService(MainServlet.java:560)
    at com.liferay.portal.servlet.MainServlet.service(MainServlet.java:537)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:72)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
    at com.liferay.portal.kernel.servlet.BaseFilter.processFilter(BaseFilter.java:163)
    at com.liferay.portal.servlet.filters.secure.SecureFilter.processFilter(SecureFilter.java:294)
    at com.liferay.portal.kernel.servlet.BaseFilter.doFilter(BaseFilter.java:57)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDoFilter(InvokerFilterChain.java:206)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:108)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilter.doFilter(InvokerFilter.java:73)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:684)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:471)
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:402)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:329)
    at com.liferay.portal.servlet.FriendlyURLServlet.service(FriendlyURLServlet.java:138)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:72)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
    at com.liferay.portal.kernel.servlet.BaseFilter.processFilter(BaseFilter.java:163)
    at com.liferay.portal.servlet.filters.gzip.GZipFilter.processFilter(GZipFilter.java:123)
    at com.liferay.portal.kernel.servlet.BaseFilter.doFilter(BaseFilter.java:57)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDoFilter(InvokerFilterChain.java:206)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:108)
    at com.liferay.portal.kernel.servlet.BaseFilter.processFilter(BaseFilter.java:163)
    at com.liferay.portal.servlet.filters.secure.SecureFilter.processFilter(SecureFilter.java:294)
    at com.liferay.portal.kernel.servlet.BaseFilter.doFilter(BaseFilter.java:57)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDoFilter(InvokerFilterChain.java:206)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:108)
    at com.liferay.portal.kernel.servlet.BaseFilter.processFilter(BaseFilter.java:163)
    at com.liferay.portal.servlet.filters.i18n.I18nFilter.processFilter(I18nFilter.java:241)
    at com.liferay.portal.kernel.servlet.BaseFilter.doFilter(BaseFilter.java:57)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDoFilter(InvokerFilterChain.java:206)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:108)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
    at com.liferay.portal.kernel.servlet.BaseFilter.processFilter(BaseFilter.java:163)
    at com.liferay.portal.servlet.filters.autologin.AutoLoginFilter.processFilter(AutoLoginFilter.java:246)
    at com.liferay.portal.kernel.servlet.BaseFilter.doFilter(BaseFilter.java:57)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDoFilter(InvokerFilterChain.java:206)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:108)
    at com.liferay.portal.kernel.servlet.BaseFilter.processFilter(BaseFilter.java:163)
    at com.liferay.portal.servlet.filters.sso.ntlm.NtlmPostFilter.processFilter(NtlmPostFilter.java:83)
    at com.liferay.portal.kernel.servlet.BaseFilter.doFilter(BaseFilter.java:57)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDoFilter(InvokerFilterChain.java:206)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:108)
    at com.liferay.portal.kernel.servlet.BaseFilter.processFilter(BaseFilter.java:163)
    at com.liferay.portal.sharepoint.SharepointFilter.processFilter(SharepointFilter.java:80)
    at com.liferay.portal.kernel.servlet.BaseFilter.doFilter(BaseFilter.java:57)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDoFilter(InvokerFilterChain.java:206)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:108)
    at com.liferay.portal.kernel.servlet.BaseFilter.processFilter(BaseFilter.java:163)
    at com.liferay.portal.servlet.filters.virtualhost.VirtualHostFilter.processFilter(VirtualHostFilter.java:216)
    at com.liferay.portal.kernel.servlet.BaseFilter.doFilter(BaseFilter.java:57)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDoFilter(InvokerFilterChain.java:206)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:108)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDirectCallFilter(InvokerFilterChain.java:187)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:95)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
    at org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:738)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDoFilter(InvokerFilterChain.java:206)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:108)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDirectCallFilter(InvokerFilterChain.java:167)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:95)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDirectCallFilter(InvokerFilterChain.java:167)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:95)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:116)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.processDirectCallFilter(InvokerFilterChain.java:187)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilterChain.doFilter(InvokerFilterChain.java:95)
    at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilter.doFilter(InvokerFilter.java:73)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:999)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:565)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:619)

1 个答案:

答案 0 :(得分：0)

您在this comment中回答了自己的问题。

因此，考虑到这一点，堆栈跟踪中的行RestaurantPortlet.java:2248将是：

adv_List.add(temp_ad); // I m guessing this might be the line: 2248

我认为您可能错过了实例化adv_List的疏忽，您目前拥有：

List<advertise> adv_List = null;

在此之后没有任何内容直接调用adv_List.add(temp_ad);，而是我们可以：

List<advertise> adv_List = new ArrayList<advertise>();

我认为这应该解决它，它很简单： - ）

与问题无关： 将您的班级名称视为小写（例如advertise，{{1}这使得它难以阅读并且不是标准的java约定。因此，你必须使用带下划线的变量，这是另一种难以阅读的内容。

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