以前用.NET实现起来很简单的东西，可是用java就是搞不出来，在给100分！真心请教，顶者有分！！！

Question

其实我要实现的功能很简单，就是像这个网站  http://www.no5.com.cn  左边的商品分类菜单,程序分别检索大类与小类的表，并显示出来。可是程我的序只显示了大类的信息,小类的确显示不出来，请高手帮看看是怎么回事，是我的逻辑错误，还是其他原因，谢谢先！！！源码如下：
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<%@ page contentType="text/html; charset=gb2312" language="java" import="java.sql.*" errorPage="" %>
<%@ page import="java.util.*" %>
<%@ page import="java.sql.*" %>
<%
Class.forName( "com.microsoft.jdbc.sqlserver.SQLServerDriver").newInstance();String  url="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=eshopDB";    String  user="sa";    
String  password="dba";  
Connection  conn=DriverManager.getConnection(url,user,password); 
Statement stmt =conn.createStatement();String sql="select *  from ProductClass";ResultSet rs = stmt.executeQuery(sql);
String classID = null ; 
%>
<table>
<!----------一级分类------------>
   <% while(rs.next())  {  
       classID= rs.getString("ClassID");
%>
    <tr>
        <td width="120" colspan="2"> 
             <a href="hello.jsp?ID=<%=rs.getString("ClassID")%>"><%=rs.getString("ClassName")%></a> 
<%}%>
</td>
    </tr><!----------二级分类------------>
<%
String m_sql="Select CategoryID,CategoryName,ClassID from ProductCategory where ClassID='"+classID+"'";
ResultSet m_rs = stmt.executeQuery(m_sql);
%>
 <% while(m_rs.next())  {  %>
    <tr>
        <td width="70"> 
             <a href="hello.jsp?ID=<%=m_rs.getString("CategoryID")%>"><%=rs.getString("CategoryName")%></a> 
 <%if(m_rs.next()){%>
        </td>
<td width="70"><a href="hello.jsp?ID=<%=m_rs.getString("CategoryID")%>"><%=m_rs.getString("CategoryName")%></a> 
<%}%>
</td>
    </tr>
   <%}%>
   <!----------------------------------------------------------------->
</table>

Answer 1

<%@ page contentType="text/html; charset=gb2312"  %>
<%@ page import="java.sql.*" %>
<%
    try{
Class.forName( "com.microsoft.jdbc.sqlserver.SQLServerDriver").newInstance();
String  url="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=eshopDB";    
String  user="sa";    
String  password="dba";  
        Connection  conn=DriverManager.getConnection(url,user,password); 
        Statement stmt =conn.createStatement();
String sql="select *  from ProductClass";
   ResultSet rs = stmt.executeQuery(sql);
        String classID = null ; 
%>
    <table>
        <!----------一级分类------------>
    <% while(rs.next())  
                    {  
        classID= rs.getString(1);
%>
     <tr>
         <td width="120" colspan="2"><a href="hello.jsp?ID=<%=classID%>"><%=rs.getString(2)%></a></td>
     </tr>
                       <!----------二级分类------------>
<%
String m_sql="Select CategoryID,CategoryName,ClassID from ProductCategory where ClassID='"+classID+"'";
ResultSet m_rs = stmt.executeQuery(m_sql);
                                while(m_rs.next()) 
                                { 
                        %>
     <tr>
         <td width="70"><a href="hello.jsp?ID=<%=m_rs.getString(1)%>"><%=m_rs.getString(2)%> </a></td>
          <%
                                                   if(m_rs.next())  
                                                     {
                                                %>
                                                     <td width="70"><a href="hello.jsp?ID=<%=m_rs.getString(1)%>"><%=m_rs.getString(2)%></a> </td>
                                                <%
                                                     }
                                                %>
                                        </tr>
                   <%
                                }
        }
             }
             catch(Exception e)
             {
                 out.println(e);
             }
    %>
</table>写的比较乱，我大致帮你看了一下

Answer 2

改了以后只显示第一张表的第一条信息与第二张表的ClassID等于第一张表ClassID的信息异常信息是：java.sql.SQLException: [Microsoft][SQLServer JDBC Driver]Object has been closed.

Answer 3

让我再来看一次，哈哈，不一定帮的了你，祝你好远。<%@ page contentType="text/html; charset=gb2312" errorPage="" %>
<%@ page import="java.util.*,java.sql.*" %>
<%
    
        String m_sql=null;
        ResultSet m_rs=null;
        String classID = null ;
    try{
        Class.forName( "com.microsoft.jdbc.sqlserver.SQLServerDriver").newInstance();
        String  url="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=eshopDB";    
String  user="sa";    
String  password="dba"; 
        Connection  conn=DriverManager.getConnection(url,user,password); 
        
%>
    <table>
        <!----------一级分类------------>
    <% 
                  Statement stmt =conn.createStatement(java.sql.ResultSet.TYPE_SCROLL_INSENSITIVE,java.sql.ResultSet.CONCUR_READ_ONLY);
          String sql="select *  from ProductClass";
             ResultSet rs = stmt.executeQuery(sql);
                    while(rs.next())  
                    {  
        classID= rs.getString(1);
%>
     <tr>
         <td width="120" colspan="2"><a href="hello.jsp?ID=<%=classID%>"><%=classID%></a></td>
     </tr>
             <!----------二级分类------------>
      <% 
                         Statement stm =conn.createStatement(java.sql.ResultSet.TYPE_SCROLL_INSENSITIVE,java.sql.ResultSet.CONCUR_READ_ONLY);
                         m_sql="Select CategoryID,CategoryName,ClassID from ProductCategory where ClassID='"+classID+"'";
         m_rs = stm.executeQuery(m_sql);
                         while(m_rs.next()) 
                         { 
                          %>
              <tr>
                     <td width="70"><a href="hello.jsp?ID=<%=m_rs.getString(3)%>"><%=m_rs.getString(4)%> </a></td>
                            <td width="70"><a href="hello.jsp?ID=<%=m_rs.getString(3)%>"><%=m_rs.getString(4)%></a> </td>
                        </tr>
                         <%
                         }
         }
             }
             catch(Exception e)
             {
                 out.println(e);
             }
    %>
</table>

Answer 4

谢谢　wsk_228(qing_feng)及所有关注此贴的兄弟

Answer 5

谢谢　wsk_228(qing_feng)好像可以了，我在试试哈