关于连接access数据库的问题!急!
我写了以下测试程序:
package Logins;
import java.sql.*;
public class Login {
String ldbdriver="sun.jdbc.odbc.JdbcOdbcDriver";
String sconstr="jdbc:odbc:driver={Microsoft Access Driver (*.mdb)};DBQ=../dbcon/login.mdb";
String pp="";
String nn="";
Connection connect=null;
Statement stmt=null;
ResultSet rs=null;
public Login(){
try {
Class.forName(ldbdriver);}
catch(java.lang.ClassNotFoundException e) {
System.err.println(e.getMessage());
}}
public ResultSet executeQuery(String sql) {
try {
connect=DriverManager.getConnection(sconstr,nn,pp); stmt=connect.createStatement(java.sql.ResultSet.TYPE_SCROLL_INSENSITIVE,java.sql.ResultSet.CONCUR_READ_ONLY); rs=stmt.executeQuery(sql);}
catch(SQLException ex) {
System.err.println(ex.getMessage());
ex.printStackTrace();
}
return rs;} }
jsp:
<%@ page contentType="text/html; charset=gb2312" language="java" import="java.sql.*" errorPage="" %>
<jsp:useBean id="condbbean" scope="page" class="Logins.Login"/>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>login</title>
</head>
<body>
<table><tr><td width="50%">name</td><td>password</td></tr>
<%
ResultSet rs_result=condbbean.executeQuery("select * from login");
String lname="";
String lpas="";
while(rs_result.next())
{lname=rs_result.getString("name");
lpas=rs_result.getString("psw");%>
<tr><td><%=lname%></td><td><%=lpas%></td></tr></table>
<%
}
rs_result.close();
%>
</body>
</html>
tomcat提示为:
type Exception report
message
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:367)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:293)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:240)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
root cause
java.lang.NullPointerException
org.apache.jsp.myweb.beatgates.TMPojiq1656rh_jsp._jspService(TMPojiq1656rh_jsp.java:75)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:136)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:320)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:293)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:240)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
是空指针吗,数据表名,字段名都没有错啊!那个jasper.JasperException
是什么意思?