如何解決對象不是在Liferay中聲明類的實例

Question

我想部署一個書籍應用程序，它將顯示一些書籍信息，並且還允許用戶添加，刪除，刪除，上傳/下載等。但是，當我嘗試部署我得到對象錯誤的應用程序不delaring類的一個實例。我不知道如何解決這個埃羅請幫助我張貼我的例外

14:13:12,567 ERROR [RuntimePageImpl-1][PortletServlet:116] javax.portlet.PortletException: java.lang.reflect.InvocationTargetException 
javax.portlet.PortletException: java.lang.reflect.InvocationTargetException 
at javax.portlet.GenericPortlet.doDispatch(GenericPortlet.java:323) 
at javax.portlet.GenericPortlet.render(GenericPortlet.java:233) 
at com.liferay.portlet.FilterChainImpl.doFilter(FilterChainImpl.java:103) 
at com.liferay.portlet.ScriptDataPortletFilter.doFilter(ScriptDataPortletFilter.java:55) 
at com.liferay.portlet.FilterChainImpl.doFilter(FilterChainImpl.java:100) 
at com.liferay.portal.kernel.portlet.PortletFilterUtil.doFilter(PortletFilterUtil.java:64) 
at com.liferay.portal.kernel.servlet.PortletServlet.service(PortletServlet.java:112) 
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728) 
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:116) 
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilter.doFilter(InvokerFilter.java:96) 
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:749) 
at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:605) 
at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:544) 
at com.liferay.portlet.InvokerPortletImpl.invoke(InvokerPortletImpl.java:604) 
at com.liferay.portlet.InvokerPortletImpl.invokeRender(InvokerPortletImpl.java:677) 
at com.liferay.portlet.InvokerPortletImpl.render(InvokerPortletImpl.java:406) 
at org.apache.jsp.html.portal.render_005fportlet_jsp._jspService(render_005fportlet_jsp.java:1242) 
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) 
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728) 
at com.liferay.portal.servlet.DirectRequestDispatcher.include(DirectRequestDispatcher.java:57) 
at com.liferay.portal.servlet.ClassLoaderRequestDispatcherWrapper.doDispatch(ClassLoaderRequestDispatcherWrapper.java:78) 
at com.liferay.portal.servlet.ClassLoaderRequestDispatcherWrapper.include(ClassLoaderRequestDispatcherWrapper.java:53) 
at com.liferay.portlet.PortletContainerImpl._doRender(PortletContainerImpl.java:655) 
at com.liferay.portlet.PortletContainerImpl.render(PortletContainerImpl.java:138) 
at com.liferay.portlet.SecurityPortletContainerWrapper.render(SecurityPortletContainerWrapper.java:141) 
at com.liferay.portlet.RestrictPortletContainerWrapper.render(RestrictPortletContainerWrapper.java:126) 
at com.liferay.portal.kernel.portlet.PortletContainerUtil.render(PortletContainerUtil.java:156) 
at com.liferay.portal.layoutconfiguration.util.PortletRenderer._render(PortletRenderer.java:120) 
at com.liferay.portal.layoutconfiguration.util.PortletRenderer.access$4(PortletRenderer.java:107) 
at com.liferay.portal.layoutconfiguration.util.PortletRenderer$PortletRendererCallable.doCall(PortletRenderer.java:174) 
at com.liferay.portal.layoutconfiguration.util.PortletRenderer$PortletRendererCallable.doCall(PortletRenderer.java:1) 
at com.liferay.portal.kernel.executor.CopyThreadLocalCallable.call(CopyThreadLocalCallable.java:69) 
at java.util.concurrent.FutureTask.run(Unknown Source) 
at com.liferay.portal.kernel.concurrent.ThreadPoolExecutor$WorkerTask._runTask(ThreadPoolExecutor.java:682) 
at com.liferay.portal.kernel.concurrent.ThreadPoolExecutor$WorkerTask.run(ThreadPoolExecutor.java:593) 
at java.lang.Thread.run(Unknown Source) 
Caused by: java.lang.reflect.InvocationTargetException 
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) 
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) 
at java.lang.reflect.Method.invoke(Unknown Source) 
at javax.portlet.GenericPortlet.doDispatch(GenericPortlet.java:319) 
... 39 more 
Caused by: java.lang.IllegalArgumentException: object is not an instance of declaring class 
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) 
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) 
at java.lang.reflect.Method.invoke(Unknown Source) 
at com.liferay.portal.kernel.bean.ClassLoaderBeanHandler.invoke(ClassLoaderBeanHandler.java:67) 
at com.sun.proxy.$Proxy418.filterRenderURL(Unknown Source) 
at com.liferay.portlet.PortletResponseImpl.doCreateLiferayPortletURL(PortletResponseImpl.java:692) 
at com.liferay.portlet.PortletResponseImpl$LiferayPortletURLPrivilegedAction.run(PortletResponseImpl.java:773) 
at com.liferay.portlet.PortletResponseImpl$LiferayPortletURLPrivilegedAction.run(PortletResponseImpl.java:1) 
at com.liferay.portal.security.lang.DoPrivilegedUtil$NoPACL.wrap(DoPrivilegedUtil.java:64) 
at com.liferay.portal.security.lang.DoPrivilegedUtil.wrap(DoPrivilegedUtil.java:26) 
at com.liferay.portlet.PortletResponseImpl.createLiferayPortletURL(PortletResponseImpl.java:267) 
at com.liferay.portlet.PortletResponseImpl.createLiferayPortletURL(PortletResponseImpl.java:259) 
at com.liferay.portlet.PortletResponseImpl.createLiferayPortletURL(PortletResponseImpl.java:281) 
at com.liferay.portlet.PortletResponseImpl.createRenderURL(PortletResponseImpl.java:291) 
at com.liferay.portlet.PortletResponseImpl.createRenderURL(PortletResponseImpl.java:286) 
at com.msh.base.BookCatalogPortlet.generateUrls(BookCatalogPortlet.java:436) 
at com.msh.base.BookCatalogPortlet.showBooks(BookCatalogPortlet.java:214) 
... 44 more 
Apr 18, 2015 2:13:12 PM org.apache.catalina.core.ApplicationDispatcher invoke 
SEVERE: Servlet.service() for servlet BookCatalog Servlet threw exception 
java.lang.IllegalArgumentException: object is not an instance of declaring class 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) 
    at java.lang.reflect.Method.invoke(Unknown Source) 
at com.liferay.portal.kernel.bean.ClassLoaderBeanHandler.invoke(ClassLoaderBeanHandler.java:67) 
at com.sun.proxy.$Proxy418.filterRenderURL(Unknown Source) 
at com.liferay.portlet.PortletResponseImpl.doCreateLiferayPortletURL(PortletResponseImpl.java:692) 
at com.liferay.portlet.PortletResponseImpl$LiferayPortletURLPrivilegedAction.run(PortletResponseImpl.java:773) 
at com.liferay.portlet.PortletResponseImpl$LiferayPortletURLPrivilegedAction.run(PortletResponseImpl.java:1) 
at com.liferay.portal.security.lang.DoPrivilegedUtil$NoPACL.wrap(DoPrivilegedUtil.java:64) 
at com.liferay.portal.security.lang.DoPrivilegedUtil.wrap(DoPrivilegedUtil.java:26) 
at com.liferay.portlet.PortletResponseImpl.createLiferayPortletURL(PortletResponseImpl.java:267) 
at com.liferay.portlet.PortletResponseImpl.createLiferayPortletURL(PortletResponseImpl.java:259) 
at com.liferay.portlet.PortletResponseImpl.createLiferayPortletURL(PortletResponseImpl.java:281) 
at com.liferay.portlet.PortletResponseImpl.createRenderURL(PortletResponseImpl.java:291) 
at com.liferay.portlet.PortletResponseImpl.createRenderURL(PortletResponseImpl.java:286) 
at com.msh.base.BookCatalogPortlet.generateUrls(BookCatalogPortlet.java:436) 
at com.msh.base.BookCatalogPortlet.showBooks(BookCatalogPortlet.java:214) 
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 javax.portlet.GenericPortlet.doDispatch(GenericPortlet.java:319) 
at javax.portlet.GenericPortlet.render(GenericPortlet.java:233) 
at com.liferay.portlet.FilterChainImpl.doFilter(FilterChainImpl.java:103) 
at com.liferay.portlet.ScriptDataPortletFilter.doFilter(ScriptDataPortletFilter.java:55) 
at com.liferay.portlet.FilterChainImpl.doFilter(FilterChainImpl.java:100) 
at com.liferay.portal.kernel.portlet.PortletFilterUtil.doFilter(PortletFilterUtil.java:64) 
at com.liferay.portal.kernel.servlet.PortletServlet.service(PortletServlet.java:112) 
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728) 
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:116) 
at com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilter.doFilter(InvokerFilter.java:96) 
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:749) 
at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:605) 
at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:544) 
at com.liferay.portlet.InvokerPortletImpl.invoke(InvokerPortletImpl.java:604) 
at com.liferay.portlet.InvokerPortletImpl.invokeRender(InvokerPortletImpl.java:677) 
at com.liferay.portlet.InvokerPortletImpl.render(InvokerPortletImpl.java:406) 
at org.apache.jsp.html.portal.render_005fportlet_jsp._jspService(render_005fportlet_jsp.java:1242) 
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) 
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728) 
at com.liferay.portal.servlet.DirectRequestDispatcher.include(DirectRequestDispatcher.java:57) 
at com.liferay.portal.servlet.ClassLoaderRequestDispatcherWrapper.doDispatch(ClassLoaderRequestDispatcherWrapper.java:78) 
at com.liferay.portal.servlet.ClassLoaderRequestDispatcherWrapper.include(ClassLoaderRequestDispatcherWrapper.java:53) 
at com.liferay.portlet.PortletContainerImpl._doRender(PortletContainerImpl.java:655) 
at com.liferay.portlet.PortletContainerImpl.render(PortletContainerImpl.java:138) 
at com.liferay.portlet.SecurityPortletContainerWrapper.render(SecurityPortletContainerWrapper.java:141) 
at com.liferay.portlet.RestrictPortletContainerWrapper.render(RestrictPortletContainerWrapper.java:126) 
at com.liferay.portal.kernel.portlet.PortletContainerUtil.render(PortletContainerUtil.java:156) 
at com.liferay.portal.layoutconfiguration.util.PortletRenderer._render(PortletRenderer.java:120) 
at com.liferay.portal.layoutconfiguration.util.PortletRenderer.access$4(PortletRenderer.java:107) 
at com.liferay.portal.layoutconfiguration.util.PortletRenderer$PortletRendererCallable.doCall(PortletRenderer.java:174) 
at com.liferay.portal.layoutconfiguration.util.PortletRenderer$PortletRendererCallable.doCall(PortletRenderer.java:1) 
at com.liferay.portal.kernel.executor.CopyThreadLocalCallable.call(CopyThreadLocalCallable.java:69) 
at java.util.concurrent.FutureTask.run(Unknown Source) 
at com.liferay.portal.kernel.concurrent.ThreadPoolExecutor$WorkerTask._runTask(ThreadPoolExecutor.java:682) 
at com.liferay.portal.kernel.concurrent.ThreadPoolExecutor$WorkerTask.run(ThreadPoolExecutor.java:593) 
at java.lang.Thread.run(Unknown Source) 

14:13:12,583 ERROR [RuntimePageImpl-1][render_portlet_jsp:132] null 
java.lang.IllegalArgumentException: object is not an instance of declaring class 
at com.liferay.portal.kernel.bean.ClassLoaderBeanHandler.invoke(ClassLoaderBeanHandler.java:67) 
at com.liferay.portlet.PortletResponseImpl.doCreateLiferayPortletURL(PortletResponseImpl.java:692) 
at com.liferay.portlet.PortletResponseImpl$LiferayPortletURLPrivilegedAction.run(PortletResponseImpl.java:773) 
at com.liferay.portlet.PortletResponseImpl$LiferayPortletURLPrivilegedAction.run(PortletResponseImpl.java:1) 
at com.liferay.portal.security.lang.DoPrivilegedUtil$NoPACL.wrap(DoPrivilegedUtil.java:64) 
at com.liferay.portal.security.lang.DoPrivilegedUtil.wrap(DoPrivilegedUtil.java:26) 
at com.liferay.portlet.PortletResponseImpl.createLiferayPortletURL(PortletResponseImpl.java:267) 
at com.liferay.portlet.PortletResponseImpl.createLiferayPortletURL(PortletResponseImpl.java:259) 
at com.liferay.portlet.PortletResponseImpl.createLiferayPortletURL(PortletResponseImpl.java:281) 
at com.liferay.portlet.PortletResponseImpl.createRenderURL(PortletResponseImpl.java:291) 
at com.liferay.portlet.PortletResponseImpl.createRenderURL(PortletResponseImpl.java:286) 
at com.msh.base.BookCatalogPortlet.generateUrls(BookCatalogPortlet.java:436) 
at com.msh.base.BookCatalogPortlet.showBooks(BookCatalogPortlet.java:214) 
at javax.portlet.GenericPortlet.doDispatch(GenericPortlet.java:319) 
at javax.portlet.GenericPortlet.render(GenericPortlet.java:233) 
at com.liferay.portlet.FilterChainImpl.doFilter(FilterChainImpl.java:103) 
at com.liferay.portlet.ScriptDataPortletFilter.doFilter(ScriptDataPortletFilter.java:55) 
at com.liferay.portlet.FilterChainImpl.doFilter(FilterChainImpl.java:100) 
at com.liferay.portal.kernel.portlet.PortletFilterUtil.doFilter(PortletFilterUtil.java:64) 
at com.liferay.portal.kernel.servlet.PortletServlet.service(PortletServlet.java:112) 
14:27:50,329 INFO [BookCatalogPortlet:180] Entering showBooks method 
14:27:50,332 INFO [BookCatalogPortlet:144] Size of the Database :4 
14:27:50,332 INFO [BookCatalogPortlet:145] Current book count in catalog : 4 
14:27:50,333 INFO [BookCatalogPortlet:506] Support portlet mode edit 
14:27:50,333 INFO [BookCatalogPortlet:506] Support portlet mode help 
14:27:50,333 INFO [BookCatalogPortlet:506] Support portlet mode view 
14:27:50,333 INFO [BookCatalogPortlet:506] Support portlet mode about 
14:27:50,333 INFO [BookCatalogPortlet:506] Support portlet mode config 
14:27:50,334 INFO [BookCatalogPortlet:506] Support portlet mode edit_defaults 
14:27:50,334 INFO [BookCatalogPortlet:506] Support portlet mode preview 
14:27:50,334 INFO [BookCatalogPortlet:506] Support portlet mode print 
14:27:50,335 INFO [BookCatalogPortlet:519] Support window state maximized 
14:27:50,335 INFO [BookCatalogPortlet:519] Support window state minimized 
14:27:50,335 INFO [BookCatalogPortlet:519] Support window state normal 
14:27:50,336 INFO [BookCatalogPortlet:519] Support window state exclusive 
14:27:50,336 INFO [BookCatalogPortlet:519] Support window state pop_up 
14:27:50,341 ERROR [RuntimePageImpl-3][PortletServlet:116]  javax.portlet.PortletException: java.lang.reflect.InvocationTargetException 
javax.portlet.PortletException: java.lang.reflect.InvocationTargetException 
at javax.portlet.GenericPortlet.doDispatch(GenericPortlet.java:323) 
at javax.portlet.GenericPortlet.render(GenericPortlet.java:233) 
at com.liferay.portlet.FilterChainImpl.doFilter(FilterChainImpl.java:103) 
at com.liferay.portlet.ScriptDataPortletFilter.doFilter(ScriptDataPortletFilter.java:55) 
at com.liferay.portlet.FilterChainImpl.doFilter(FilterChainImpl.java:100) 
at com.liferay.portal.kernel.portlet.PortletFilterUtil.doFilter(PortletFilterUtil.java:64) 

這些GenerateUrls（）和showBooks （）方法

private void generateUrls(RenderRequest request, RenderResponse response) 
     throws PortletModeException, WindowStateException { 
    // Render URL for Print hyperlink 
    PortletURL printModeUrl = response.createRenderURL(); 
    if (request.isPortletModeAllowed(new PortletMode("print"))) { 
     printModeUrl.setPortletMode(new PortletMode("print")); 
    } 
    if (request.isWindowStateAllowed(new WindowState("pop_up"))) { 
     printModeUrl.setWindowState(new WindowState("pop_up")); 
    } 
    request.setAttribute("printModeUrl", printModeUrl); 

    // Action URL for upload Toc action 
    PortletURL uploadTocActionUrl = response.createActionURL(); 
    uploadTocActionUrl.setParameter("myaction", "uploadTocAction"); 
    uploadTocActionUrl.setParameter(ActionRequest.ACTION_NAME, 
      "uploadTocAction"); 
    request.setAttribute("uploadTocActionUrl", uploadTocActionUrl); 

    // Render URL for Full Screen hyperlink 
    PortletURL fullScreenUrl = response.createRenderURL(); 
    fullScreenUrl.setWindowState(WindowState.MAXIMIZED); 
    request.setAttribute("fullScreenUrl", fullScreenUrl); 

    // Render URL for Help hyperlink 
    PortletURL helpUrl = response.createRenderURL(); 
    helpUrl.setPortletMode(PortletMode.HELP); 
    request.setAttribute("helpUrl", helpUrl); 

    // Render URL for Home hyperlink 
    PortletURL homeUrl = response.createRenderURL(); 
    homeUrl.setPortletMode(PortletMode.VIEW); 
    request.setAttribute("homeUrl", homeUrl); 

    // Render URL for Preferences hyperlink 
    PortletURL prefUrl = response.createRenderURL(); 
    prefUrl.setPortletMode(PortletMode.EDIT); 
    request.setAttribute("prefUrl", prefUrl); 

    // Render URL for form submission for Adding book 
    PortletURL addBookFormUrl = response.createRenderURL(); 
    addBookFormUrl.setParameter("myaction", "addBookForm"); 
    request.setAttribute("addBookFormUrl", addBookFormUrl); 

    // Action URL for Add Book Action 
    PortletURL addBookActionUrl = response.createActionURL(); 
    addBookActionUrl.setParameter(ActionRequest.ACTION_NAME, 
      "addBookAction"); 
    request.setAttribute("addBookActionUrl", addBookActionUrl); 

    // Action URL for resetting search 
    PortletURL resetActionUrl = response.createActionURL(); 
    resetActionUrl.setParameter(ActionRequest.ACTION_NAME, "resetAction"); 
    request.setAttribute("resetActionUrl", resetActionUrl); 

    // Action URL for searching books 
    PortletURL searchBookActionUrl = response.createActionURL(); 
    searchBookActionUrl.setParameter(ActionRequest.ACTION_NAME, 
      "searchBookAction"); 
    request.setAttribute("searchBookActionUrl", searchBookActionUrl); 

    // Render URL for Refresh Search Results link 
    PortletURL refreshResultsUrl = response.createRenderURL(); 
    refreshResultsUrl.setParameter("myaction", "refreshResults"); 
    request.setAttribute("refreshResultsUrl", refreshResultsUrl); 
} 

@SuppressWarnings("unchecked") 
@RenderMode(name = "VIEW") 
public void showBooks(RenderRequest request, RenderResponse response) 
     throws Exception { 
    logger.info("Entering showBooks method"); 

    //--return if the content is still valid 
    if(isMarkupValid(request, response)) { 
     response.getCacheControl().setUseCachedContent(true); 
     response.getCacheControl().setExpirationTime(100); 
     return; 
    } else { 
     BookDataObject catalog = (BookDataObject) getPortletContext() 
     .getAttribute("bookCatalog"); 
     int currentCountInDatastore = catalog.getBooks().size(); 
     // -- set the currentCountInDatabase as the etag value 
     response.getCacheControl().setETag("" + currentCountInDatastore); 
    } 

    PortalContext context = request.getPortalContext(); 
    printSupportedPortletModes(context); 
    printSupportedWindowStates(context); 
    // --get user attributes user.name.given and user.name.family 
    Map<String, Object> userAttributeMap = (Map<String, Object>) request 
      .getAttribute(PortletRequest.USER_INFO); 
    String firstName = ""; 
    String lastName = ""; 
    if (userAttributeMap != null) { 
     firstName = (String) userAttributeMap.get("user.name.given"); 
     lastName = (String) userAttributeMap.get("user.name.family"); 
     request.setAttribute("firstName", firstName); 
     request.setAttribute("lastName", lastName); 
    } 

    String portalInfo = context.getPortalInfo(); 
    request.setAttribute("portalInfo", portalInfo); 

    // --generate all the URLs that will be used by the portlet 
    generateUrls(request, response); 

    String myaction = request.getParameter("myaction"); 
    if (myaction != null) { 
     logger.info("myaction parameter is not null. Value is " + myaction); 
     request.getPortletSession().setAttribute("myaction", myaction, 
       PortletSession.PORTLET_SCOPE); 
    } else { 
     // -- if myaction is NULL then show the home page of Book 
     // catalog 
     // page 
     request.getPortletSession().setAttribute("myaction", "showCatalog", 
       PortletSession.PORTLET_SCOPE); 
    } 

    // -- send myaction as a request attribute to the BookServlet. 
    request.setAttribute("myaction", request.getPortletSession() 
      .getAttribute("myaction")); 

    // --dynamically obtain the title for the portlet, based on myaction 
    String titleKey = "portlet.title." 
      + (String) request.getPortletSession().getAttribute("myaction"); 
    response.setTitle(getResourceBundle(request.getLocale()).getString(
      titleKey)); 

    // --if the action is uploadTocForm then store the ISBN number of 
    // the 
    // --book for which the TOC is being uploaded. The upload action 
    // will use the ISBN number to create file name -- refer home.jsp 
    // page 
    if (((String) request.getAttribute("myaction")) 
      .equalsIgnoreCase("uploadTocForm")) { 
     request.getPortletSession().setAttribute("isbnNumber", 
       request.getParameter("isbnNumber")); 
    } 

    if (((String) request.getPortletSession().getAttribute("myaction")) 
      .equalsIgnoreCase("showSearchResults")) { 
     request.setAttribute("matchingBooks", request.getPortletSession() 
       .getAttribute("matchingBooks")); 
    } 

    // its important to encode URLs 
    PortletRequestDispatcher dispatcher = request.getPortletSession() 
      .getPortletContext().getRequestDispatcher(
        response.encodeURL("/myservlet/bookServlet")); 
    dispatcher.include(request, response); 
} 

Answer 1

我的猜測是在你的showBooks（）或generateUrls （）方法將對象轉換爲另一個對象，或者對非法對象執行某些操作。如果你可以在上述兩種方法中發佈代碼，我可以給你一個更好的答案。

Answer 2

由於問題在於堆棧跟蹤的深入，我的猜測是在類路徑中有一些文件不應該在那裏，或者在那裏有兩次。確保你在appserver的全局類路徑中有portlet.jar，而不是你的webapp的WEB-INF/lib。 portal-impl.jar也是如此，應該在Liferay中生存，但在其他地方 - 無論是全局還是應用程序。

此外，它可能有助於標記一些行號。你在代碼中有幾個response.createRenderURL的外觀，並且很好地知道問題是在第一次出現還是在一段時間之後。