JSP 中访问数据库，如果查询的是多个表，那么RS.get..()中怎么确定类啊？

我知道如果是单个表，只要用1，2，3。。代替列名或直接用列名就OK了，多表怎么搞？

解决方案 »

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你在select里面写什么就是什么么嘛select a.name,b.id from table1 a,table2 b where a.id=b.idrs.getString(name);
或者rs.getString(1)
谢谢楼上大哥，我还有问题问：
我用JSP访问数据库（是ACCESS库）一直不成功，TOMCAT报错内容是：
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
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:372)
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)
root cause java.lang.NullPointerException
org.apache.jsp.test526_jsp._jspService(test526_jsp.java:83)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:324)
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.
------------------------------------------------------------------------------------------
JSP页面代码是：
<%@ page contentType="text/html;charset=gb2312"language="java"%>
<%@ page import="java.sql.*"%>
<jsp:useBean id="connDbBean"scope="page"class="a.conn"/><HTML>
<HEAD>
<TITLE> New Document </TITLE></HEAD>
<div align="center">
   <table width="75%"border="2">
    <tr>
<td width="25%">
  <div align="center"><font><b>¶¨µ¥</b></font></div>
</td>
<td width="25%">
  <div align="center"><font><b>¹ºÂòÎïÆ·</b></font></div>
</td>
<td width="25%">
  <div align="center"><font><b>ÊýÁ¿</b></font></div>
</td>
<td width="25%">
  <div align="center"><font><b>½ð¶î</b></font></div>
</td>
</tr>
<%ResultSet RS_result=connDbBean.executeQuery("select idOrder,description,quantity,unitPrice*quantity from orderDetails ,products where orderDetails.idProduct=products.idProduct");
long idor=0;
String dscr="";
long quant=0;
double unitpr=0;
while (RS_result.next())
{
  idor=RS_result.getLong(1);
  dscr=RS_result.getString(2);
  quant=RS_result.getLong(3);
  unitpr=RS_result.getDouble(4);
  %>
  <TR>
   <TD width="25%"><div align="center"><%=idor%></div></TD>
   <TD width="25%"><div align="center"><%=dscr%></div></TD>
   <TD width="25%"><div align="center"><%=quant%></div></TD>
    <TD width="25%"><div align="center"><%=unitpr%></div></TD>
  </TR>
  <%
}
  RS_result.close();
  %>
  </table>
<BODY></BODY>
</HTML>
------------------------------------------------------------------------------------------
下边是BEAN的代码：
package a;
import java.sql.*;
public class conn
{

String DBDRIVER = "sun.jdbc.odbc.JdbcOdbcDriver";
String Connstr = "jdbc:odbc:ts";
        Connection connect = null;
        ResultSet rs=null; public conn()
{
try
{
Class.forName(DBDRIVER);
}
catch (java.lang.ClassNotFoundException e)
{
System.err.println( e.getMessage());
}

}

public ResultSet executeQuery(String sql)
{
try
{ connect=DriverManager.getConnection(Connstr);
Statement stmt = connect.createStatement();
rs = stmt.executeQuery(sql);
}
catch(SQLException ex)
{System.err.println(ex.getMessage());
}

return rs;
}
}
对啊我把JSP代码中WIHLE以下的屏蔽，然后Out.print(RS_result),结果输出的是NULL，请哪位好心的帮解决下吧，在线等咯
Out.print(RS_result)加上判断if为null则替换成“”即可
不是jsp页面的错误，应该是数据库联接或数据源的错误，因为rs=stmt.executeQuery(sql)，不管有没有结果，肯定会返回一个ResultSet实例，不可能为null