jsp 中import 自己的包，报错，package does not exist

大家帮我看下是何原因jsp：
<%@ page language="java" contentType="text/html; charset=GB18030" pageEncoding="GB18030"%>
<%@ page import="java.sql.*"%>
<%@ page import="java.util.*"%>
<%@ page import="com.dao.*"%><%@ page import="java.util.List" %>
        <head>
                <meta http-equiv="Content-Type" content="text/html; charset=GB18030">
                <link rel="StyleSheet" href="css/dtree.css" type="text/css" />
                <script type="text/javascript" src="js/dtree.js"></script>
 
 <div class="dtree">
                        <p>
                                <a href="javascript: d.openAll();">open all</a> |
                                <a href="javascript: d.closeAll();">close all</a>
                        </p>
                        <table>
                      <tr>
                      <td></td>
                      </tr>
                        <script type="text/javascript">
                <%
                String sql="select * from treeinfo1";
                NodesImpl nodesImpl = new NodesImpl();
                List list=nodesImpl.query(sql);
                Iterator iterator = list.iterator(); 
                while(iterator.hasNext()){ 
                Nodes treenode = (Nodes)iterator.next(); 
                if(treenode.getPid()==0){ 
                %> 
                d.add(<%=treenode.getId()%>,<%=treenode.getPid()%>,'<%=treenode.getName()%>') 
                <%}else{%> 
                d.add(<%=treenode.getId()%>,<%=treenode.getPid()%>,'<%=treenode.getName()%>',parent.getUrlByCatalogId('<%=treenode.getId()%>'),null,'list'); 
                <%}}%>  </script>
  </table>
                </div>        
 </head>
        <title></title>
        <body></body>
</html>===================================
错误提示：
HTTP Status 500 - --------------------------------------------------------------------------------type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception org.apache.jasper.JasperException: Unable to compile class for JSPGenerated servlet error:
C:\Program Files\Apache Software Foundation\Tomcat 5.0\work\Catalina\localhost\videoTraning\org\apache\jsp\left2_jsp.java:8: package com.dao does not exist
import com.dao.*;
^
An error occurred at line: 22 in the jsp file: /left2.jsp
Generated servlet error:
C:\Program Files\Apache Software Foundation\Tomcat 5.0\work\Catalina\localhost\videoTraning\org\apache\jsp\left2_jsp.java:70: cannot find symbol
symbol  : class NodesImpl
location: class org.apache.jsp.left2_jsp
                NodesImpl nodesImpl = new NodesImpl();
                ^
An error occurred at line: 22 in the jsp file: /left2.jsp
Generated servlet error:
C:\Program Files\Apache Software Foundation\Tomcat 5.0\work\Catalina\localhost\videoTraning\org\apache\jsp\left2_jsp.java:70: cannot find symbol
symbol  : class NodesImpl
location: class org.apache.jsp.left2_jsp
                NodesImpl nodesImpl = new NodesImpl();
                                          ^
An error occurred at line: 22 in the jsp file: /left2.jsp
Generated servlet error:
C:\Program Files\Apache Software Foundation\Tomcat 5.0\work\Catalina\localhost\videoTraning\org\apache\jsp\left2_jsp.java:74: cannot find symbol
symbol  : class Nodes
location: class org.apache.jsp.left2_jsp
                Nodes treenode = (Nodes)iterator.next(); 
                ^
An error occurred at line: 22 in the jsp file: /left2.jsp
Generated servlet error:
C:\Program Files\Apache Software Foundation\Tomcat 5.0\work\Catalina\localhost\videoTraning\org\apache\jsp\left2_jsp.java:74: cannot find symbol
symbol  : class Nodes
location: class org.apache.jsp.left2_jsp
                Nodes treenode = (Nodes)iterator.next(); 
                                  ^
5 errors org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:84)
org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:332)
org.apache.jasper.compiler.Compiler.generateClass(Compiler.java:412)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:472)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:451)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:439)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:511)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:295)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
note The full stack trace of the root cause is available in the Apache Tomcat/5.0.28 logs.