再问简单问题!JSP方面的。
megin 2005-03-27 10:05:52 我的JSP文件如下:
<%@page contentType="text/html;charset=GB2312" import="java.sql.*"%>
<html>
<title>用JavaBean查询数据库</title>
<body>
<%@ page language="java" %>
<jsp:useBean id="QueryBean" scope="session" class="beal.QueryBean"/>
<%
Connection conn=QueryBean.setConnection("");
ResultSet rs=QueryBean.getQuery("select top 10 ,vTitle,vArticle,id from tb_article");
%>
<table border="1">
<tr bgcolor="pink"><th>姓名</th><th>部门</th><th>分机号码</th></tr>
<%
while(rs.next())
{
%>
<tr><td><%=rs.getString("vTitle")%></td>
<td><%=rs.getString("vArticle")%></td>
<td align="center"><%=rs.getInt("id")%></td></tr>
<%
}
%>
</table>
</body>
</html>
javabean文件如下:
package beal;
import java.sql.*;
public class QueryBean
{
private Connection conn=null;
private ResultSet rs=null;
private String dbs;
public QueryBean()
{
}
public Connection setConnection(String db)
{
dbs="jdbc:odbc:jdbc:odbc:personal"+db;
try
{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
conn=DriverManager.getConnection(dbs,"sa",db);
}
catch (Exception e)
{
System.out.println(e.toString());
}
return conn;
}
public ResultSet getQuery(String sqls)
{
try
{
Statement statement=conn.createStatement();
rs= statement.executeQuery(sqls);
}
catch (Exception e)
{
System.out.println(e.toString());
}
return rs;
}
}
现在出现如下的错误:
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:358)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
root cause
java.lang.NullPointerException
org.apache.jsp.select_jsp._jspService(select_jsp.java:66)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:133)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:311)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
note The full stack trace of the root cause is available in the Tomcat logs.
以上错误如何解决呀!