jsp连数据库遇到的有关问题,请高手帮忙

2013-09-11

jsp连数据库遇到的问题,请高手帮忙数据库连接类package DBConnimport java.sql.*public class DataBaseC

jsp连数据库遇到的问题,请高手帮忙
数据库连接类
package DBConn;
import java.sql.*;
public class DataBaseConn{
String url="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=student";
String user="sa";
String psw="";

String drivername="com.microsof.jdbc.sqlserver.SQLServerDriver";

ResultSet rs=null;
Statement stmt=null;
Connection conn=null;
public DataBaseConn(){}

public void openconn()throws Exception{
try{
Class.forName(drivername);
conn=DriverManager.getConnection(url,user,psw);
}
catch(Exception e){
System.out.println(e.getMessage());
}

}

public ResultSet executeQuery(String sql){
try{
stmt=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_READ_ONLY);
rs=stmt.executeQuery(sql);
}
catch(SQLException e){
System.err.println("executeQuery:"+e.getMessage());
}
return rs;
}

public void executeUpdate(String sql){
try{
stmt=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_READ_ONLY);
stmt.executeUpdate(sql);
}
catch(Exception e){
System.err.println("executeUpdate:"+e.getMessage());
}
}

public void closeconn(){
try{
conn.close();
}
catch(Exception e){
System.out.println(e);
}
}

public void closestmt(){
try{
stmt.close();
}
catch(Exception e){
System.out.println(e);
}
}
}

jsp

<%@ page contentType="text/html;charset=gb2312"%>
<%@ page import="java.sql.*" %>
<jsp:useBean id="db" scope="session" class="DBConn.DataBaseConn">
</jsp:useBean>
<html>
<body>
<table>
<tr>
<%!String sql="select sid from stu";

String s="";
%>
<% db.openconn();
ResultSet rs=db.executeQuery(sql);
while(rs.next()){
s=rs.getString(1);
}
%>
<td><%=s %></td>
</tr>
</table>
</body>
</html>

运行时出现的问题

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: An exception occurred processing JSP page /test.jsp at line 14

11: String s="";
12: %>
13: <% db.openconn();
14: ResultSet rs=db.executeQuery(sql);
15: while(rs.next()){
16: s=rs.getString(1);
17: }

Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:505)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:416)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:337)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)

javax.servlet.http.HttpServlet.service(HttpServlet.java:803)

root cause

java.lang.NullPointerException
DBConn.DataBaseConn.executeQuery(DataBaseConn.java:28)
org.apache.jsp.test_jsp._jspService(test_jsp.java:79)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:337)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)

note The full stack trace of the root cause is available in the Apache Tomcat/6.0.16 logs.

--------------------------------------------

搞了一天了,还是解决不了

[解决办法]
楼主看看你的 drivername，写的什么？呵呵
一定是报ClassNotFoundException！！

Java code

数据库连接类 package DBConn; import java.sql.*; public class DataBaseConn{ String url="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=student"; String user="sa"; String psw=""; String drivername="com.microsof.jdbc.sqlserver.SQLServerDriver";
我的异常网推荐解决方案：An exception occurred processing JSP page,http://www.myexception.cn/j2se/33144.html
我的异常网推荐解决方案：The server encountered an internal error () that prevented it from fulfilling this request.,http://www.myexception.cn/java-web/317.html

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jsp连数据库遇到的有关问题,请高手帮忙