Jsp+Bean+Access连接数据库问题
操作系统:winxp
数据库Access2000,库名:student,表名table1,(其中字段为name(char),sex(char),score(num))
Apache Tomcat Ver: 5.0.28
已在控制面板里把ODBC源配置好.
1,conn.java(bean模块,连接数据库用)
2,conn_db.jsp(显示模块,显示table1里的数据)
问题:不能显示正确内容.
其源代码如下:
1,文件名:conn.java
package student;
import java.sql.*;
import java.io.*;
public class conn {
private String sDBDriver = "sun.jdbc.odbc.JdbcOdbcDriver";
private String sConnStr = "jdbc:odbc:student";
private Connection connect = null;
private ResultSet rs = null;
private Statement stmt = null;
public conn() {
try {
Class.forName(sDBDriver);
}
catch(java.lang.ClassNotFoundException e) {
System.err.println( e.getMessage());
}
}
public ResultSet executeQuery(String sql) {
try {
connect = DriverManager.getConnection(sConnStr);
stmt = connect.createStatement();
rs = stmt.executeQuery(sql);
}
catch(SQLException ex) {
System.err.println(ex.getMessage());
}
return rs;
}
}
//已把该java程序用命令javac conn.java -d . 生成一个conn.class文件,并在student文件夹里.
//并且把该student文件夹与其class文件放到WEB-INF\classes里.
2,文件名:conn_db.jsp
<%@ page contentType="text/html;charset=GBK" %>
<%@ page language="java" import="java.sql.*" %>
<jsp:useBean id="connDbBean" scope="page" class="student.conn"/>
<html>
<head>
<title>test db connection</title>
</head>
<body bgcolor="#FFFFFF">
<div align="center">
<table width="60%" border="1">
<tr bgcolor="#CCCCFF">
<td width="50%">
<div align="center"><font color="#FF0033"><b>姓名</b></font></div>
</td>
<td width="25%">
<div align="center"><font color="#FF0033"><b>性别</b></font></div>
</td>
<td width="25%">
<div align="center"><font color="#FF0033"><b>分数</b></font></div>
</td>
</tr>
<%
ResultSet RS_result = connDbBean.executeQuery("select * from table1");
String studentName="";
String studentSex="";
int studentScore=0;
while(RS_result.next())
{
studentName = RS_result.getString("name");
studentSex = RS_result.getString("sex");
studentScore = RS_result.getInt("score");
%>
<tr>
<td width="50%" bgcolor="#FFFFFF">
<div align="center"><%=studentName%></div>
</td>
<td width="25%">
<div align="center"><%=studentSex%></div>
</td>
<td width="25%">
<div align="center"><%=studentScore%></div>
</td>
</tr>
<%
}
RS_result.close();
%>
</table>
</body>
</html>
/////////////////////////////////////////////////////////////////////////////////////
执行conn_db.jsp后,出现以下错误提示:
HTTP Status 500 -
--------------------------------------------------------------------------------
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: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._08.conn_005fdb_jsp._jspService(conn_005fdb_jsp.java:77)
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.
--------------------------------------------------------------------------------
Apache Tomcat/5.0.28
/////////////////////////////////////////////////////////
请教各位兄弟,解决办法!谢谢!