java.lang.NullPointerException(连接数据库问题！)

passwords 2003-09-01 01:06:44

在连接SQLserver2000时出问题，麻烦大家给看看！
----------------------------class part------------------------------------
package Com.yy.yuran;
import java.sql.*;

/**
* <p>Title: </p>
* <p>Description: </p>
* <p>Copyright: Copyright (c) 2003</p>
* <p>Company: </p>
* @author unascribed
* @version 1.0
*/

public class OpenDb {
public static String DbDriver="sun.jdbc.odbc.JdbcOdbcDriver";
public static String DSN="jdbc:odbc:yuran";
public static String user="sa";
public static String password="yuran";
public Connection conn=null;
public Statement stmt=null;
public ResultSet rs=null;
public OpenDb() {try{
Class.forName(DbDriver);
}catch(ClassNotFoundException e){
e.printStackTrace();
System.err.println("OpenDb()"+e.getMessage());
}
}
//查询并显示数据库内容//
public ResultSet ExecuteQuery(String sql) throws SQLException{
try{
conn=DriverManager.getConnection(DSN,user,password);
stmt=conn.createStatement();
rs=stmt.executeQuery(sql);
}catch(SQLException e){
System.err.println("SQLException"+e.getMessage());
}catch(Exception e){
e.printStackTrace();
}finally{
return rs=null;
}
}
}
-----------------------------------jsp part-------------------------------
<%@ page contentType="text/html; charset=GBK" %>
<%@ page import="Com.yy.yuran.OpenDb"%>
<%@ page import="java.sql.*"%>
<html>
<head>
<title>
ryxx
</title>
</head>
<body>
<h1 align=center>
显示数据库内容
</h1>
<% OpenDb open=new OpenDb();
ResultSet rs=null;
String sql="select * from ryxx";
rs=open.ExecuteQuery(sql);
out.println("<table border=1 align=center width=600>");
while(rs.next()){
out.println("<tr><td>"+rs.getInt(1)+"</td></td>"+rs.getString(2)+"</td><td>"+rs.getString(3)+"</td><td>"+rs.getInt(4)+"</td><td>"+rs.getInt(5)+"</td></tr>");
}
out.println("<table>");
%>
</body>
</html>
--------------------------------------end---------------------------------
运行后出现错误（java.lang.NullPointerException）

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