Connect problem with JDBC in javaBean and JSP

From: "gaox" <gaox(at)mountor(dot)com>
To: <pgsql-jdbc(at)postgresql(dot)org>
Subject: Connect problem with JDBC in javaBean and JSP
Date: 2002-06-12 05:38:09
Message-ID: 000b01c211d3$565dba70$2100a8c0@mountor33
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Lists: pgsql-jdbc

I try to write a bean to deal with all the operation of the database. Here are the codes:

import java.sql.*;
import java.util.*;

public class ConnectDB {
String error;
Connection con;

public void connect () throws ClassNotFoundException,
SQLException,
Exception {
try {
Class.forName("org.postgresql.Driver");
con = DriverManager.getConnection("jdbc:postgresql:test","postgres","");
}
catch (ClassNotFoundException cnfe) {
error = "ClassNotFoundException: Could not locate DB driver.";
throw new ClassNotFoundException (error);
}
catch (SQLException sqle) {
error = "SQLException: Could not connect to database.";
throw new Exception (error);
}
catch (Exception e) {
error = "Exception: An unknown error occurred while connecting to database.";
throw new Exception (error);
}
}

public void disconnect () throws SQLException {
try {
if ( con != null ) {
con.close();
}
}
catch (SQLException sqle) {
error = "SQLException: Unable to close the database connection.";
throw new SQLException (error);
}
}

public ResultSet viewDatabase () throws SQLException, Exception {
ResultSet rs = null;
try {
String queryString = "Select * From test;";
Statement stmt = con.createStatement();
rs = stmt.executeQuery(queryString);
}
catch (SQLException sqle) {
error = "SQLException : Could not execute the query.";
throw new SQLException (error);
}
catch (Exception e) {
error = "Exception: An unknown error occurred while test.";
throw new Exception (error);
}
return rs;
}
}

and the JSP is :

<%@ page language="java" import="java.sql.*, java.io.*, java.util.*" %>
<%@ page contentType="text/html;charset=gb2312"%>
<jsp:useBean id="test" class="ConnectDB" />

<html>
<head><title> test database </title></head>

<body>
<table width="85%" border="1">
<%
test.connect ();

ResultSet rs = test.viewDatabase ();

while (rs.next()) {
%>
<tr>
<td><%=rs.getInt("i")%></td>
<td><%=rs.getString("name")%></td>
</tr>
<%
}

test.disconnect ();
%>
</table>
<p>&nbsp;</p>
</body>
</html>

The environment is Redhat 7.2, postgreSQL 7.2, j2sdk1.4.0, Tomcat 4.0.3
and the parameter CLASSPATH contains the /usr/local/pgsql/share/pgjdbc2.jar
While I browse the page, it is said

javax.servlet.ServletException: ClassNotFoundException: Could not locate DB driver.
at org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:463)
at org.apache.jsp.list$jsp._jspService(list$jsp.java:134)
........

However, I can run my java application to connect the database and show the
records in it well. What's wrong? Thanks a lot for help!

yours Xiang Gao

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