新人求助，新鲜出炉的异常-CSDN论坛

⋅求助：在for循环到第三个的时候数据输出异常 ⋅import java.util.*;为什么无法把该包下的类都导入呢 ⋅私有内部类不能通过外部类来创建吗 更多帖子 关注私信空间博客 爪蛙爱踢程序猿 等级 本版专家分：55 结帖率 50%: 17:17:09,447 [http-apr-8080-exec-3] ERROR RequestUtils : Error creating form bean of class  cn.itcast.bbs.web.struts.forms.CategoryForm ==> org.apache.struts.util.RequestUtils.createActionForm(RequestUtils.java:304)
java.lang.NullPointerException
at org.apache.struts.config.FormBeanConfig.createActionForm(FormBeanConfig.java:212)
at org.apache.struts.util.RequestUtils.createActionForm(RequestUtils.java:292)
at org.apache.struts.util.RequestUtils.createActionForm(RequestUtils.java:191)
at org.apache.struts.action.RequestProcessor.processActionForm(RequestProcessor.java:331)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:202)
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:620)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2441)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2430)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)
17:17:09,450 [http-apr-8080-exec-3] ERROR RequestProcessor : No action instance for path /category could be created ==> org.apache.struts.action.RequestProcessor.processActionCreate(RequestProcessor.java:296)
java.lang.ClassNotFoundException:  cn.itcast.bbs.web.struts.actions.CategoryAction
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1718)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1569)
at org.apache.struts.util.RequestUtils.applicationClass(RequestUtils.java:117)
at org.apache.struts.util.RequestUtils.applicationInstance(RequestUtils.java:143)
at org.apache.struts.action.RequestProcessor.processActionCreate(RequestProcessor.java:292)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:230)
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:620)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2441)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2430)
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)

struts-config.xml文件
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts-config PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 1.2//EN" "http://struts.apache.org/dtds/struts-config_1_2.dtd">

<struts-config>
  <data-sources />
  <form-beans>
   <form-bean name="categoryForm" type=" cn.itcast.bbs.web.struts.forms.CategoryForm"/>

  </form-beans>
  <global-exceptions />
  <global-forwards />

  <action-mappings>
   
   <action path="/category" type=" cn.itcast.bbs.web.struts.actions.CategoryAction
" parameter="method"
   name="categoryForm" scope="request" validate="false">

   <forward name="list" path="WEB-INF/pages/category/list.jsp"></forward>
   <forward name="add" path="WEB-INF/pages/category/add.jsp"></forward>
   <forward name="edit" path="WEB-INF/pages/category/edit.jsp"></forward>
   <forward name="showCategories" path="/category.do"></forward>
  </action>

  </action-mappings>
  <message-resources parameter="cn.itcast.bbs.web.struts.ApplicationResources" />
</struts-config>

CategoryForm.java文件
package cn.itcast.bbs.web.struts.forms;

import javax.servlet.http.HttpServletRequest;

import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionMapping;

@SuppressWarnings("serial")
public class CategoryForm extends ActionForm {
private int id;
private String name;

public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
//完成categoryForm.validate方法
@Override
public ActionErrors validate(ActionMapping mapping,
HttpServletRequest request) {
return super.validate(mapping, request);
}

}

CategoryAction.java文件
package cn.itcast.bbs.web.struts.actions;

import java.util.List;

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.action.ActionMessages;
import org.apache.struts.actions.DispatchAction;

import cn.itcast.bbs.domain.Category;
import cn.itcast.bbs.service.CategoryService;
import cn.itcast.bbs.web.service.impl.CategoryServiceImpl;

public class CategoryAction extends DispatchAction {

protected CategoryService categoryService = new CategoryServiceImpl();
/**
* 列表
*/
@Override
protected ActionForward unspecified(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {

List<Category> categories = categoryService.findAll();
request.setAttribute("categories", categories);
return mapping.findForward("list");
}

/**
* 添加页面
*/
public ActionForward addUI(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {

return mapping.findForward("add");
}
/**
* 添加
*/
public ActionForward add(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
// 校验错误，转发,自己校验formBean
ActionMessages errors = form.validate(mapping, request);
if(errors!=null && errors.size()>0){
saveErrors(request,errors);
return addUI(mapping,form,request,response);
}

//调用业务方法添加Category
return mapping.findForward("showCategories");
}
/**
* 修改页面
*/
public ActionForward editUI(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {

return mapping.findForward("edit");
}

/**
* 修改
*/
public ActionForward edit(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {

return mapping.findForward("showCategories");
}
/**
* 删除
*/
public ActionForward del(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {

return mapping.findForward("edit");
}

/**
* 调整顺序（上下移动）
*/
public ActionForward changeOrder(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {

return mapping.findForward("showCategories");
}

}

2014-11-15 17:21:30

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