第一次接触struts，一个logic:iterate问题，各位帮忙呀，做不下去了!!!

vgvg，我改了你说的地方，可还是不行？
小弟菜鸟，还得请各位帮助啊，怎么没人回答呢？

StuffActionForm.setStufflist(v);////
加上httpServletRequest.setAttribute("stuffshowActionForm",StuffActionForm);jsp页面也相应的改一下

vgvg:jsp应该怎么改呢？可以解释一下改的意思吗？

vgvg:我急呀!帮帮忙，把代码按照struts流程都改了，贴上来，关建的地方，写上说明，小弟感激呀!

改了一下你的BEAN,你再试试.
一、bean(showStuff)package hongmei.insert;import hongmei.database.DBConn;
import java.sql.*;
import java.util.*;public class showStuff{
  private String id;
  private String stuffName;
  private String re;

  public void setId(String id){
    this.id=id;
  }
  public String getId(){
    return id;
  }
  public void setStuffName(String stuffName){    this.stuffName=stuffName;
  }
  public String getStuffName(){
    return stuffName;
  }
  public void setRe(String re){
    this.re=re;
  }
  public String getRe(){
    return re;
  }
  public showStuff() {
  }
  public showStuff(String id,String stuffName,String re) throws Exception
  {
    this.id=id;
    this.stuffName=stuffName;
    this.re=re;
  }  public Collection getAllstuffshow() throws Exception
  {
    showStuff s=null;//modi
    Collection v=new ArrayList();//modi
    DBConn conn=new DBConn();
    String sql="select ID,Stuff_Name,Re from StuffName_Table";
    ResultSet rsstuff = conn.executeQuery(sql);
      while(rsstuff.next()){
s=new showstuff();//modi
        s.id=Integer.toString(rsstuff.getInt("ID"));
        s.stuffName=rsstuff.getString("Stuff_Name");
        s.re=rsstuff.getString("Re");
        v.add(s);
        System.out.println(s.id +" "+s.stuffName+" "+s.re);
      }
      conn.finalize();    return v;
  }
}

这个BEAN没问题了，可我要怎么样才能通过 action 到 actionform ，最后让 login:iterate 得到呢？

我又重新改了一下，可还是不行？提示错误：Cannot find bean a in any scope ，再帖出来，请大家帮着看看。楼上的，我知道这样看着好累，我的确不知道怎么办了，见谅!
一、数据BEAN(StuffName)
package hongmei.insert;public class StuffName {
  public StuffName() {
  }
  private String id;
    private String stuffName;
    private String re;    public void setId(String id){
      this.id=id;
    }
    public String getId(){
      return id;
    }
    public void setStuffName(String stuffName){      this.stuffName=stuffName;
    }
    public String getStuffName(){
      return stuffName;
    }
    public void setRe(String re){
      this.re=re;
    }
    public String getRe(){
      return re;
    }
}二、查询BEAN(showStuff)
package hongmei.insert;import hongmei.database.DBConn;
import hongmei.insert.StuffName;
import java.sql.*;
import java.util.*;public class showStuff{
  StuffName stuffname=null;
  Collection v;
  public showStuff() {
    v=new Vector();
  }
  public Collection getAllstuffshow() throws Exception
  {
    stuffname=new StuffName();
    DBConn conn=new DBConn();
    String sql="select ID,Stuff_Name,Re from StuffName_Table";
    ResultSet rsstuff = conn.executeQuery(sql);
      while(rsstuff.next()){
        stuffname=new StuffName();
        stuffname.setId(Integer.toString(rsstuff.getInt("ID")));
        stuffname.setStuffName(rsstuff.getString("Stuff_Name"));
        stuffname.setRe(rsstuff.getString("Re"));
        v.add(stuffname);
        System.out.println(stuffname.getId() +" "+stuffname.getStuffName()+" "+stuffname.getRe());
      }
      conn.finalize();    return v;
  }
  public static void main(String args[]){
    showStuff b=new showStuff();
    Collection k=new ArrayList();
    try{
      k=b.getAllstuffshow();
      if(k.isEmpty()){
        System.out.println("空的空的空的");
      }
      else{
        System.out.println("实的实的实的");//这个BEAN是得到内容的
      }
    }
    catch(Exception e){
      System.out.print(e.getMessage());
    }
  }
}
三、Action(stuffshowAction)
package hongmei;import org.apache.struts.action.*;
import javax.servlet.http.*;
import hongmei.insert.showStuff;
import java.util.*;
public class stuffshowAction extends Action {
  public ActionForward perform(ActionMapping actionMapping, ActionForm actionForm, HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) {
    /**@todo: complete the business logic here, this is just a skeleton.*/
    //throw new java.lang.UnsupportedOperationException("Method perform() not yet implemented.");
    //stuffshowActionForm StuffActionForm=(stuffshowActionForm)actionForm;
    //ArrayList v;
    Collection a;
    showStuff showstuff;
    try{
      showstuff=new showStuff();
     // a=new ArrayList();
      a=showstuff.getAllstuffshow();
   //   StuffActionForm.setStufflist(a);
      httpServletRequest.setAttribute("a",a);      }
    catch(Exception e){
      System.out.println(e.getMessage());
    }
    return new ActionForward("Success");
  }
}
四、jsp(stuffshow.jsp)
<%@ page contentType="text/html; charset=UTF-8" %>
<%@ taglib uri="/WEB-INF/struts-logic.tld" prefix="logic" %>
<%@ taglib uri="/WEB-INF/struts-template.tld" prefix="template" %>
<%@ taglib uri="/WEB-INF/struts-bean.tld" prefix="bean" %>
<%@ taglib uri="/WEB-INF/struts-html.tld" prefix="html" %>
<link rel="stylesheet" href="images/style.css" type="text/css">
<link rel="stylesheet" href="images/ebb.css" type="text/css">
<html:html>
<head>
<title>
<bean:message key="hongmei.title"/>
</title>
</head>
<body>
<html:form action="/stuffshowAction.do" method="POST">
<table width="80%"  border="0" cellspacing="0" cellpadding="0" align="center">
  <tr>
    <th width="18%" align="center" scope="col"><bean:message key="hongmei.del"/></th>
    <th width="33%" align="center" scope="col"><bean:message key="hongmei.name"/></th>
    <th width="49%" align="center" scope="col"><bean:message key="hongmei.re"/></th>
  </tr>
<logic:iterate id="stuffName" name="a">
<tr>
     <td width="18%" align="center" scope="col"><bean:write name="stuffName"
property="id"/></td>
     <td width="33%" align="center" scope="col"><bean:write name="stuffName"
property="stuffName"/></td>
     <td width="49%" align="center" scope="col"><bean:write name="stuffName"
property="re"/></td>
  </tr>
</logic:iterate>
</table>
</html:form>
</body>
</html:html>

指出2点:
1. 之所以出现Cannot find bean a in any scope 的问题是因为没有关于bean:define关于a的定义就直接用了,只要加如下形式的定义<bean:define id="a" property="xxx" name="xxxxxxForm"/>就可解决该问题
2.楼主的代码存在一个潜在的问题,你没有判断logic:iterate的数据源是否为空, 如果一旦指定数据源为空时就会报会出现Tag can't set to null的错误
  现给出一段我以前写过的代码,希望能对楼主有所帮助(该工程已经实施了一年多了,代码应该是没有问题的,不过老早写的代码可能不是很规范,^_^)

<%--注意:要对数据源判断，否则会出现Tag can't set to null错误--%>
        <logic:notEqual property="dataSources" name="prjMngForm" value="">
        <bean:define id="arr" property="dataSources" name="prjMngForm"/>
        <%
        int no=0;
        %>
        <logic:iterate  id="prjInfoID"  offset="<%=String.valueOf(no)%>" name="arr">
        <a target="_parent" href="prjMngAction.do?prjCode=<bean:write name="prjInfoID" property="prjCode"/>">
        <tr onmouseover="this.style.backgroundColor='#CEE0F0';this.style.cursor='hand';this.title='点击查看详细信息';" onmouseout="this.style.backgroundColor='';" <%if (no%2==0) {%> bgcolor="white" <%;} else {%> bgcolor="#f7f7ef"<%;}%>>
          <td height="14" valign="middle"> <div align="center"><%=no+1%></div></td>
          <td><bean:write name="prjInfoID" property="prjVoltageLevel"/></td>
          <td><bean:write name="prjInfoID" property="prjName"/></td>
          <td><bean:write name="prjInfoID" property="prjMainCapacity"/></td>
          <td><bean:write name="prjInfoID" property="lineLength"/></td>
          <logic:equal name="prjInfoID" property="PZGS" value="0.0">
          <td align="right"><font color="#0033FF"><bean:write name="prjInfoID" property="CSGS"/></font></td>
          </logic:equal>
          <logic:notEqual name="prjInfoID" property="PZGS" value="0.0">
          <td align="right"><bean:write name="prjInfoID" property="PZGS"/></td>
          </logic:notEqual>
          <td align="right"><bean:write name="prjInfoID" property="prjRunPlan"/></td>
          <%no=no+1;%>
        </tr>
        </a>
        </logic:iterate>
        </logic:notEqual>

StuffActionForm.setStufflist(v);
------
加上httpServletRequest.setAttribute("stuffshowActionForm",StuffActionForm);

你结果出现空值是因为你有两个错误:
1.在Bean中s对象没有构造函数.
2.v没有初始化getAllstuffshow类应该改为:
所以你的  public Collection getAllstuffshow() throws Exception
  {
    DBConn conn=new DBConn();
    String sql="select ID,Stuff_Name,Re from StuffName_Table";
    ResultSet rsstuff = conn.executeQuery(sql);

    v=new ArrayList();      //初始化对象      while(rsstuff.next()){

        s=new showStuff();  //每条记录作为一个showStuff对象,进行构造函数        s.id=Integer.toString(rsstuff.getInt("ID"));
        s.stuffName=rsstuff.getString("Stuff_Name");
        s.re=rsstuff.getString("Re");
        v.add(s);
        System.out.println(s.id +" "+s.stuffName+" "+s.re);
      }
      conn.finalize();    return v;
  }
其它的地方应该不用改了,不过boneeater(狗狗)的意见很好,最好在jsp中取值的时候先看看是不是为空,如果你不做判断的化,如果结果是空,程式就会出现错误.在jsp中改成:

<table width="80%"  border="0" cellspacing="0" cellpadding="0" align="center">
  <tr>
    <th width="18%" align="center" scope="col"><bean:message key="hongmei.del"/></th>
    <th width="33%" align="center" scope="col"><bean:message key="hongmei.name"/></th>
    <th width="49%" align="center" scope="col"><bean:message key="hongmei.re"/></th>
  </tr>

  <logic:notEmpty name="stuffshowActionForm" property="stufflist">     //判断当值不为空时在执行 <logic:iterate id="stufflist" name="stuffshowActionForm" property="stufflist"
                type="hongmei.insert.showStuff">
<tr>
     <td width="18%" align="center" scope="col"><bean:write name="stufflist"
property="id"/></td>
     <td width="33%" align="center" scope="col"><bean:write name="stufflist"
property="stuffName"/></td>
     <td width="49%" align="center" scope="col"><bean:write name="stufflist"
property="re"/></td>
  </tr>
</logic:iterate>
   </logic:notEmpty>  //结束标签
</table>

</body>
</html:html>

liaohaiying(小菜):加了这句，可不知道真正的意思，页面不知道怎么处理？

我急死了，页面还是没有数据，有没有愿意直接在我电脑上解决问题的(用netmeeting,我给共享)？再附加50分，说到做到。如果愿意，加我QQ：421013 。先谢谢了!!

加QQ时，注明 csdn 解决问题,

调试易

第一次接触struts，一个logic:iterate问题，各位帮忙呀，做不下去了!!!

解决方案 »