Hi,
connection pooling will not be handled automatically. U will have to write a
class for it. Open the connections and put them in a hashtable and access
them whenever needed. I am not sure abt tomcat but weblogic app server
provides you connection pooling facility.
Following code is taken from Oreillys' Java Servlet programming by Hunter
and Croford.
import java.sql.*;
import java.util.*;
public class ConnectionPool {
private Hashtable connections;
private int increment;
private String dbURL, user, password;
public ConnectionPool(String dbURL,
String user,
String password,
String driverClassName,
int initialConnections,
int increment)
throws SQLException, ClassNotFoundException {
// Load the specified driver class
Class.forName(driverClassName);
this.dbURL = dbURL;
this.user = user;
this.password = password;
this.increment = increment;
connections = new Hashtable();
// Put our pool of Connections in the Hashtable
// The FALSE value indicates they're unused
for(int i = 0; i < initialConnections; i++) {
connections.put(DriverManager.getConnection(dbURL, user, password),
Boolean.FALSE);
}
}
public Connection getConnection() throws SQLException {
Connection con = null;
Enumeration cons = connections.keys();
synchronized (connections) {
while(cons.hasMoreElements()) {
con = (Connection)cons.nextElement();
Boolean b = (Boolean)connections.get(con);
if (b == Boolean.FALSE) {
// So we found an unused connection.
// Test its integrity with a quick setAutoCommit(true) call.
// For production use, more testing should be performed,
// such as executing a simple query.
try {
con.setAutoCommit(true);
}
catch(SQLException e) {
// Problem with the connection, replace it.
con = DriverManager.getConnection(dbURL, user, password);
}
// Update the Hashtable to show this one's taken
connections.put(con, Boolean.TRUE);
// Return the connection
return con;
}
}
}
// If we get here, there were no free connections.
// We've got to make more.
for(int i = 0; i < increment; i++) {
connections.put(DriverManager.getConnection(dbURL, user, password),
Boolean.FALSE);
}
// Recurse to get one of the new connections.
return getConnection();
}
public void returnConnection(Connection returned) {
Connection con;
Enumeration cons = connections.keys();
while (cons.hasMoreElements()) {
con = (Connection)cons.nextElement();
if (con == returned) {
connections.put(con, Boolean.FALSE);
break;
}
}
}
}
Hope this will solve your problem.
Regards,
shishir.
>From: Aaron Crandall <[EMAIL PROTECTED]>
>Reply-To: A mailing list about Java Server Pages specification and
> reference <[EMAIL PROTECTED]>
>To: [EMAIL PROTECTED]
>Subject: Connection pooling?
>Date: Tue, 9 Jan 2001 16:35:31 -0700
>
>Hello all,
>
>I am creating a JSP application that will run on Tomcat and access a SQL
>Server database using standard javabeans. My question is this: what do I
>have to do to use connection pooling? Will it happen automatically if I use
>a driver that supports it? Or do I have to write a Connection pooling
>class?
>
>Thanks in advance for any help!
>
>Aaron
>
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>
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