Creating connection using Connection Pooling!
I am getting the Connection object from the pool!
my application has series of servlets & JSPs wherein some pages only use the connection object and run some SQL queries!
now, I want to get the Connection object once & for all, and then use it wherever I need it. How do I make this happen? How does the Connection object go to the other pages??
Not needed. Let each method that needs one, get one from the pool. The pool does not open a new connection every time a connection is asked for (only when there are not any available connections left) so the overhead of opening a new connection is not present. This is the entire purpose of a connection pool.
If, however, you absolutely must do something like this, then you can pass it as an argument to every method that needs it (they of course have to declare a Connection parameter). Just don't close it, or it goes back to the pool.
Similar Messages
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Unable to connect using connect string in linus using sys user in Linux
Hi,
I am facing problem in using connect string while connecting as sys user in Linux OS
For example:
When I am connecting as
sys/sysoracle as sysdba its getting connected.
But when I am providing the connect string such as sys/sysoracle@TEST as sysdba its showing with error as:
ORA-12505: TNS :listener does not currently know of SID in connect descriptor
Any help will be benefitial for me
Thanks and Regards>
ORA-12505:
TNS:listener does not currently know of SID given in connect descriptor
Cause: The listener received a request to establish a connection to a database or other service. The connect descriptor received by the listener specified a SID for an instance (usually a database instance) that either has not yet dynamically registered with the listener or has not been statically configured for the listener. This may be a temporary condition such as after the listener has started, but before the database instance has registered with the listener.
Action:
- Wait a moment and try to connect a second time.
- Check which instances are currently known by the listener by executing: lsnrctl services <listener name>
- Check that the SID parameter in the connect descriptor specifies an instance known by the listener.
- Check for an event in the listener.log file.>
So are you sure that TEST is a right connection string that you are using and is rightly configured?
HTH
Aman.... -
Error while creating a new DAC connection using connection type MSSQL
Hi,
I am trying to create a new DAC connection i.e. a new DAC repository in the SQL Server 2008 database.
DAC version : 10.1.3.4.1
Database : SQL Server 2008
I have downloaded the sqljdbc4.jar file from the below link and placed it in the D:\orahome\10gR3_1\bifoundation\dac\lib folder.
[http://www.microsoft.com/en-us/download/details.aspx?displaylang=en&id=11774 ]
I have entered all the details correctly for database name, database host, database port. I created a new Authentication file.
I get the below error when I try to test the connection.
MESSAGE:::MSSQL driver not available!
EXCEPTION CLASS::: java.lang.IllegalArgumentException
com.siebel.etl.gui.login.LoginDataHandler$LoginStructure.testConnection(LoginDataHandler.java:512)
com.siebel.etl.gui.login.LoginDataHandler.testConnection(LoginDataHandler.java:386)
com.siebel.etl.gui.login.ConnectionTestDialog$Executor.run(ConnectionTestDialog.java:290)
::: CAUSE :::
MESSAGE:::com.microsoft.sqlserver.jdbc.SQLServerDriver
EXCEPTION CLASS::: java.lang.ClassNotFoundException
java.net.URLClassLoader$1.run(URLClassLoader.java:200)
java.security.AccessController.doPrivileged(Native Method)
java.net.URLClassLoader.findClass(URLClassLoader.java:188)
java.lang.ClassLoader.loadClass(ClassLoader.java:306)
sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:276)
java.lang.ClassLoader.loadClass(ClassLoader.java:251)
java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
java.lang.Class.forName0(Native Method)
java.lang.Class.forName(Class.java:169)
com.siebel.etl.gui.login.LoginDataHandler$LoginStructure.testConnection(LoginDataHandler.java:510)
com.siebel.etl.gui.login.LoginDataHandler.testConnection(LoginDataHandler.java:386)
com.siebel.etl.gui.login.ConnectionTestDialog$Executor.run(ConnectionTestDialog.java:290)
The error seems to be a connectivity issue with SQL Server. Am I using the correct jar file?
Please help me out in resolving this issue. Appreciate the help provided on this forum earlier.
Thank YouAdd
.\lib\sqljdbc4.jar
at end of the line starting with SQLSERVERLIB in config.bat file
Pls mark correct -
Problem using connection pooling on netbeans with mysql
Hi everyone,
I use Apache Tomcat server 5.0 and Mysql as back end. I have done connection pooling in tomcat server installation folder and everything works fine.But when I tried the same on netbeans I could not connect using connection pooling and it's throwing error as
'Name jdbc is not bound in this Context'.
When I checked the tomcat server in netbeans it says a version of tomcat 5.5.9(May be netbean's tomcat).So is there anything to be changed for server.xml of higher version tomcat above 5.0?
I need your help to solve this issue.
thanks in advance
-JeganHi everyone,
I use Apache Tomcat server 5.0 and Mysql as back end. I have done connection pooling in tomcat server installation folder and everything works fine.But when I tried the same on netbeans I could not connect using connection pooling and it's throwing error as
'Name jdbc is not bound in this Context'.
When I checked the tomcat server in netbeans it says a version of tomcat 5.5.9(May be netbean's tomcat).So is there anything to be changed for server.xml of higher version tomcat above 5.0?
I need your help to solve this issue.
thanks in advance
-Jegan -
Get Connection from connection pooling
Hi,
I am aware of the fact that to get connection from a connection pool we need to add JNDI name in context.xml of apache tomcat and use it in our application to get connection. I have tested this and it works fine.
Now, we have 12 servers having free database each having almost 20 small Java applications for different purposes (get data from server database do some business logic and maipulation with data from central database and store on central database) each connecting to central database.
We were enjoying life till we had almost 8-9 servers but now many times we have connection issues as there are too many connections to central database and servers are going to increase.
I know my company design is not good but we need some solution.
I want my Java applications to take database connectivity using connection pooling on servers. My Java applications are standalone applications that do not run in web server. Is this approach fine?
I searched google for some solution but was unable to find.
Any pointers would be really helpful.
I think that since my application is outside web container I am unable to get Context (java:/comp/env). Please give me some pointers on how can i get web server context outside web server.
Thanks and Regards,
Vikash Anand.Google ( [jndi standalone application|http://www.google.com/search?q=jndi+standalone+application] ).
-
Create ZONE in ZFS pool solaris10
Hi Gurus,
I'm reading some solaris 10 tutorials about ZFS and Zones. Is it possible to create a new storage pool using my current hard disk in which I installed solaris???
I'm a bit new in Solaris, I have a SPARC box in which I'm learnin about solaris 10. I have installed Solaris 10 using ZFS file system. I think my box only have 1 disk but not sure. I see 46 GB of free space running "df -kh " command
I run "format" command, this is the output
root@orclidm # format
Searching for disks...done
AVAILABLE DISK SELECTIONS:
0. c0t0d0 <SUN72G cyl 14087 alt 2 hd 24 sec 424>
/pci@780/pci@0/pci@9/scsi@0/sd@0,0
1. c0t1d0 <SUN72G cyl 14087 alt 2 hd 24 sec 424>
/pci@780/pci@0/pci@9/scsi@0/sd@1,0
Specify disk (enter its number):
zpool list "display this:"
root@orclidm # zpool list
NAME SIZE ALLOC FREE CAP HEALTH ALTROOT
rpool 68G 13.1G 54.9G 19% ONLINE -
zfs list "display this:"
root@orclidm # zfs list
NAME USED AVAIL REFER MOUNTPOINT
rpool 21.3G 45.6G 106K /rpool
rpool/ROOT 11.6G 45.6G 31K legacy
rpool/ROOT/s10s_u10wos_17b 11.6G 45.6G 11.6G /
rpool/dump 1.50G 45.6G 1.50G -
rpool/export 66K 45.6G 32K /export
rpool/export/home 34K 45.6G 34K /export/home
rpool/swap 8.25G 53.9G 16K -
I read in a tutorial that when you create a zpool you need to specify an empty hard disk, is that correct?
Please point me on the best approach to create zones using zfs pools.
Regardsmanin21 wrote:
Hi Gurus,
I'm reading some solaris 10 tutorials about ZFS and Zones. Is it possible to create a new storage pool using my current hard disk in which I installed solaris???IF you have a spare partition you may use that.
>
I'm a bit new in Solaris, I have a SPARC box in which I'm learnin about solaris 10. I have installed Solaris 10 using ZFS file system. I think my box only have 1 disk but not sure. I see 46 GB of free space running "df -kh " command
I run "format" command, this is the output
root@orclidm # format
Searching for disks...done
AVAILABLE DISK SELECTIONS:
0. c0t0d0 <SUN72G cyl 14087 alt 2 hd 24 sec 424>
/pci@780/pci@0/pci@9/scsi@0/sd@0,0
1. c0t1d0 <SUN72G cyl 14087 alt 2 hd 24 sec 424>
/pci@780/pci@0/pci@9/scsi@0/sd@1,0
Specify disk (enter its number):
This shows two disks. In a production setup you might mirror this.
zpool list "display this:"
root@orclidm # zpool list
NAME SIZE ALLOC FREE CAP HEALTH ALTROOT
rpool 68G 13.1G 54.9G 19% ONLINE -
The command:
zpool status
would show you what devices you are using
zfs list "display this:"
root@orclidm # zfs list
NAME USED AVAIL REFER MOUNTPOINT
rpool 21.3G 45.6G 106K /rpool
rpool/ROOT 11.6G 45.6G 31K legacy
rpool/ROOT/s10s_u10wos_17b 11.6G 45.6G 11.6G /
rpool/dump 1.50G 45.6G 1.50G -
rpool/export 66K 45.6G 32K /export
rpool/export/home 34K 45.6G 34K /export/home
rpool/swap 8.25G 53.9G 16K -
I read in a tutorial that when you create a zpool you need to specify an empty hard disk, is that correct?
No.
You can use partions/slices instead. A zone storage pool is composed of one or more devices; each device can be a a whole disk, disk slice or even a file if i remember correctly ( .... but you really dont want to use a file normally).
Please point me on the best approach to create zones using zfs pools.
RegardsYour storage rpool is 68GB in size on a 72GB disk .... therefore the disk is full up and their is no space for another zfs pool. If zpool status shows your disk is mirrored by zfs that is that. Otherwise you may choose to create a storage pool on the other disk (not best production practice).
often one creates a zfs filesystem out of an existing filesystem.
zfs create -o mountpoint=/zones rpool/zones
zfs create rpool/zones/myzone
Then use zonepath=/zones/myzone creating the zone.
- I was googling to cross check my answer ... the following blog has an example but it is a little old and may be opensolaris orientated.
https://blogs.oracle.com/DanX/entry/solaris_zfs_and_zones_simple
Authorative information is at http://docs.oracle.com, notably:
http://docs.oracle.com/cd/E23823_01/index.html
http://docs.oracle.com/cd/E23823_01/html/819-5461/index.html
http://docs.oracle.com/cd/E18752_01/html/817-1592/index.html -
How do i use Connection pool in JSP pages
Hey everyone,
I am using a connection pool in my web application. I am using DbConnectionBroker from Javaexchange.com. It has a class that creates a connection pool available for the servlets. I am trying to figure out that how to use connection pool within the JSP pages if I want to connect to the database. In the servlets i am using DBConnectionBroker pool = (DbConnectionBroker) getServletContext().getAttribute("dbPool") to get database connection. How Can i use this in JSP page to get a db connection.
ThanksIf the reference to the connection pool is already stored as an ServletContex attribute, try:
<jsp:useBean id="dbPool" scope="application" class="com.javaexchange.dbConnectionBroker" />
<%
Connection con = dbPool.getConnection();
%> -
Failed to obtain/create connection from connection pool after redeploy
I have a web application (.war) that uses a jdbc connection pool. The application works fine, however after I redeploy it using the administration console I get "Failed to obtain/create connection from connection pool [ Datavision_Pool ]. Reason : null" followed by "Error allocating connection : [Error in allocating a connection. Cause: null]" from javax.enterprise.resource.resourceadapter and I am forced to restart the instance. I am running Sun Java System Application Server 9.1 (build b58g-fcs)
using a connection pool to a Microsoft SQL 2000 database using inet software's JDBC drivers. I need to be able to redeploy applications without having to restart the instance. Any help is appreciated.I have turned on some additional diagnostics and found out some answers and a work-around, but I think that there may be a bug in the way JDBC connection pool classes are loaded. The actual error was a null pointer in the JDBC driver class in the perpareStatement method. The only line in this method is "return factory.createPreparedStatement( this , sql );" and the only possible NPE would be if the factory was null, which should be impossible because it is a static variable and it is initialized when the class is loaded. The problem occurs because we deploy the JDBC driver .jar file within our .war file, for use when a client doesn't have or want to use connection pooling. Apparently, the connection pool must have picked up some of these classes and when the .war was redeployed, the reference to the factory was lost for existing connections (not sure how). If I remove the JDBC .jar file from the .war, it works, but that wasn't an ideal solution, the other way to get it to work was to change the sun-web.xml file to have <class-loader delegate="true">. We previously had it set to false in version 8.1 because of interference with a different version of the apache Tiles classes, which has now been addressed in version 9.1.
I still think there is an issue, because the connection pool should never use the application specific classloaders. Am I wrong to believe this? -
How to use Connection Pool in ADF ear file creaion from jDev 10.1.3
Hi,
We are developing big application in ADF with 10 different modules. We are creating ear file with data source setting.
How to use connection pool while creating ear file from jDev. Connection pool is alreday created in Application Server 10g.
What all the setting we need do to make use of connection pool while creating ear file jDev.
ThanksUser,
If you are using ADF Business Components, you can right-click each application module, select "configurations" and edit the configuration you are using. On the initial page of the configuration dialog, you can specify to use either a JDBC URL or a Datasource - you just need to choose Datasource and then provide the name by which to access it.
John -
How to dynamically validate users at run time using connection pools ?
Hi Folks
We are facing a peculiar situation . We have established connection to our
oracle 8i database using Oracle Thin driver using conenction pooling at the weblogic
server . We set up connection pools at the console to set up connections to thge
oracle 8i database. However the user name and password is always static when
we create the connection pool at the console .
How do i dynamically validate other users using the same connection pool ??
Eg - The connection pool at design time in the console uses user A and password
- passA . Now at run time lets say I prompt the user for a login screen and want
to trap the user id and apssword parameters entered by the user and use it with
the connection pool created earlier . I tried using the below code snippet :-
Properties props = new Properties();
props.put("connectionPoolID", "Oracle_Thin_Driver_Pool");
props.put("user" , userId );
props.put("password",userPass);
myDriver = (Driver) Class.forName("weblogic.jdbc.pool.Driver").newInstance();
conn = myDriver.connect("jdbc:weblogic:pool", props);
But always it connects to the database using the userid and password set in the
console while creating the connection pool . So how i get the connection pool
to validate my current userid and password entered through the login screen ??
Thanks in advance
KeithHey Bob.
So I assume you're -completely- working with built executables? You're not going to work in the editor environment to modify your projects at all?
If this is the case, then having a generic deployment phase at the beginning of the executable (with a "setting up hardware for your app" splash screen) isn't a bad idea -
Check the binary on the target, ensure it matches the binary you have on the host machine (in case you ever decide to update).
If they don't match, FTP the new file down to replace the old one.
FTP the ni-rt.ini file, ensure the startup exe is enabled and is pointing to the correct location.
If it's not enabled or not pointing to the correct startup file, modify the .INI file and FTP back to the target.
If you had to update the INI file, ask target to reboot itself. Wait 30 seconds, and wait for target to become available again.
Connect to the target. If you cannot connect, reboot target. If the target comes back and you still cannot connect to the app, notify user.
That's almost exactly how we handle installation and deployment via MAX.
The big assumption here is that the built executables were all built with the same version of LabVIEW Real-Time. If not, you'd need a system replication step in there to make sure the proper version of LabVIEW is on the target before launching the built .rtexe.
-Danny -
Problem in using connection pool in netbeans
Hi,
I am using Net Beans and Sun java application server and Derby as database.
I have created data connnection and also configure JDBC resources (ie. DataResource and connectionPool).
Now i want to use this connection pool in my class, I have create one DataConnection class and put this code
private javax.sql.DataSource getMyDatabase () throws javax.naming.NamingException {
javax.naming.Context c = new javax.naming.InitialContext();
return (javax.sql.DataSource) c.lookup("java:comp/env/jdbc/myDatabase");
}I got this code by right click and selecting Enterprise Resources->Use Data, But while running i got the exception
javax.naming.NoInitialContextException: Need to specify class name in environment or system property, or as an applet parameter, or in an application resource file: java.naming.factory.initial
Plz tell me How can we overcome this exception and is there any other way do use connection pool.
Thanks.Thanks bamkin-ov-lesta,
DbConnectionBroker is good for servlet or other java application. If i use this class, it is like i am writing code for connection pool. I am using NetBeans and sun java application server which provide its default connection pool configuration and i want to use that only.
And I am not getting which class name to be set in environment variable under what name in the following exception.
javax.naming.NoInitialContextException: Need to specify class name in environment or system property, or as an applet parameter, or in an application resource file: java.naming.factory.initial
Help me plz. -
How to use connection pool in struts
hai
I have created my own connection pool class. I need to use the connection pool in my struts application. Can anyone tell me where and how to implement ,Please....
Thanks in advance.User,
If you are using ADF Business Components, you can right-click each application module, select "configurations" and edit the configuration you are using. On the initial page of the configuration dialog, you can specify to use either a JDBC URL or a Datasource - you just need to choose Datasource and then provide the name by which to access it.
John -
ORA-22990 ( Cannot span lob... ) while using connection pooling...
Hi all, I am maintaining a web site that has lots of requests ( about 10 requests a second ) to an Oracle table that has a BLOB field. Those requests create new blobs, updates them and reads them... My program worked fine until I started using connection pooling ( Before that, I used a single connection that was initialized at startup ). Although I had to synchronized the methods that interact with blob field, everything worked great. So now, to optimize my site, I want to use connection pooling so that even if my methods are synchonized on the connection object, there will be more than one connection available so it will not affect performance.
So once I introduced my connection pooling system with the oracle.jdbc.pool.OracleConnectionCacheImpl class, I started getting ORA-22990 ( Cannot span lob objects... ). I get the error on the flush() method when I try to write the blob to the database. Here is my function that writes a row in the databse.
private synchronized void writeSession(CapSession pSession) throws Exception
javax.sql.PooledConnection pc = pool.getPooledConnection();
Connection conn = pc.getConnection();
CallableStatement stmt=conn.prepareCall(writeObjSQL);
stmt.setString(1,pSession.getSessionId()+pSession.getPassword());
stmt.setLong(2,pSession.getLastAccess());
stmt.setLong(3,pSession.getTimeout());
stmt.registerOutParameter(4,java.sql.Types.BLOB);
stmt.executeUpdate();
oracle.sql.BLOB blob=(BLOB)stmt.getBlob(4);
OutputStream os=blob.getBinaryOutputStream();
ObjectOutputStream oop=new ObjectOutputStream(os);
oop.writeObject(pSession);
oop.flush();
oop.close();
os.close();
stmt.close();
conn.commit();
conn.close();
pc.close();
} If anyone could help me, I would deeply appreciate it!
Thank you for your time.kalle
Thank you very much for your advice!!!
Like you said, I started to check whether the connections are fine before giving them from the pool.I am executing a simple "select 'anil' from dual" and if its fine only then I return the connection. So far it seems to be fine. Also I am reopening the connections(closing the old ones and opening new connections) after every 12 hours.
As far as the JDBC driver is concerned, I already tried with Oracle 8i driver, it gave the same problems. I read that 9i driver might solve this problem, so I changed to the latest 9i driver (classes12_g.zip).
Sometimes before(before I started checking whether the connection is good )the application used to hang up at the point where I am issuing setAutoCommit(false).It never comes out from that statement.Is this something to do with theconnections being closed?
What I am afraid is, will the appilation get hung up even after I check the connection with select query and then issue autocommit(false)??
Or will it hang up while I check with a select query??
As long as it doesn't hung up, I am fine. Because i am cathching the exceptions.
Thanks In ADVANCE
Anil -
Repost-Best way of using connection pooling
I am reposting this, seems best suitable in this category.
I am using Eclipse 3.1 along with Tomcat 5.0, MySQL 4.1, J2EE1.4. I could set up the JNDI Dataresource connection pooling and tested with small test servlet. Now thinking of having common methods for getting connection / closing / commiting ....etc.
I wrote following. [Please let me know whether it is correct way of doing it - as i am not very sure]
package common;
import java.sql.*;
import javax.sql.*;
import javax.naming.*;
import org.apache.log4j.Logger;
public final class connectionManager {
private static Logger logger = Logger.getLogger(common.connectionManager.class);
public connectionManager() {}
public static Connection getConn () throws NamingException, SQLException
//JNDI DataSource connection pooling
Connection conn = null;
try{
Context initContext = new InitialContext();
Context envContext = (Context)initContext.lookup("java:/comp/env");
DataSource ds = (DataSource)envContext.lookup("jdbc/TQ3DB");
conn = ds.getConnection();
}catch (NamingException ne) {
new GlobalExceptionHandler(logger, ne);
conn = null;
throw new NamingException();
}catch (SQLException e){
new GlobalExceptionHandler(logger, e);
conn = null;
throw new SQLException();
return conn;
}//getConnection
public static void commit(Connection conn) throws SQLException
conn.commit();
public static void rollback(Connection conn) throws SQLException
conn.rollback();
public static void setAutoCommit(Connection conn, boolean autoCommit)
throws SQLException
conn.setAutoCommit(autoCommit );
public static void closeConnection(Connection conn) throws SQLException{
if (conn != null) {
conn.close();
conn = null;
}//closeConnection
public static void closeResources(ResultSet oRS, PreparedStatement pstmt) throws SQLException
if (oRS != null) {
oRS.close();
oRS = null;
if (pstmt != null) {
pstmt.close();
pstmt = null;
} // closeResources
}//ConnectionManager
I am having a login form which submits user name and password. I am checking this against the database. Following is the servlet to do that.
package login;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.*;
import common.*;
public class loginServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}//doGet
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException,IOException{
String userId = request.getParameter("userId");
String password = request.getParameter("password");
** call a method to validate the password which will return the
** User Name for authorized users and null string for un-authorised.
String uName = validateUser(userId, password);
//if uName is null .. user is not authorized.
if (uName == null){
//redirect to jsp page with error message
RequestDispatcher rd =
getServletContext().getRequestDispatcher("/jsps/mainmenu.jsp");
if (rd != null){
rd.forward(request,response);
else{
// the user is valid - create a seesion for this user.
HttpSession userSession = request.getSession(true);
// put the user name session variable.
userSession.setAttribute("userName", uName);
//redirect to Main menu page
RequestDispatcher rd =
getServletContext().getRequestDispatcher("/jsps/mainmenu.jsp");
if (rd != null){
rd.forward(request,response);
}// end of doPost
private String validateUser(String userId, String password)
throws SQLException{
String returnVal = null;
connectionManager cm = new connectionManager();
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet oRS = null;
try{
//get the connection
conn = cm.getConn ();
//get records from user table for this user id and password
String sQry = "SELECT user_login FROM user "
+ "where user_login = ? AND user_pwd = ? ";
pstmt = conn.prepareStatement(sQry);
pstmt.setString(1, userId);
pstmt.setString(2, password);
oRS = pstmt.executeQuery();
//check for record
if (oRS.next()) {
returnVal = oRS.getString("user_login");
}else {returnVal = null;}
}catch (Exception e){
returnVal = null;
}finally{
cm.closeResources(oRS, pstmt);
cm.closeConnection(conn);
return returnVal;
}// end of servlet class
But i am unable to compile it and i am also getting lots of warnings.
I am getting error at line
1)String uName = validateUser(userId, password);
Unhandled exception type SQLException loginServlet.java TQ3/WEB-INF/src/login line
Following warnings:
2)For loginServlet Declaration
The serializable class DBTest does not declare a static final serialVersionUID field of type long loginServlet.java
3)The static method getConn() from the type connectionManager should be accessed in a static way
4)The static method closeResources(ResultSet, PreparedStatement) from the type connectionManager should be accessed in a static way
5)The static method closeConnection(Connection) from the type connectionManager should be accessed in a static way
Definitely I am doing it wrong but exactly where? I am having very strong doubt the way i am using connections is not the correct way. Pls help me.
regards
ManishaI am in a search of best way to use connection pooling. Initially was using simple JDBC call, then modified to JNDI, afterwards tried to have common class. Later came accross the idea of Singleton/Static. I wanted to have a common class which will handle all connection related issues and at the same time give good performance.
With due respect to all Java Gurus: i got all from web articles/tutorials/java forum etc. There is a long discussion regarding Singlet vs static in this forum. But finally got confused and could not figure out in my case which method shall i make use of, so tried both.
What I want is somebody pointing out flwas inside my 2 code snippets and guide me about which method shall i adopt in future.
Static way:
package common;
import java.sql.Connection;
import javax.sql.DataSource;
import java.sql.SQLException;
import javax.naming.InitialContext;
import javax.naming.NamingException;
public final class ConnectionManager_Static {
private static InitialContext ctx = null;
private static DataSource ds = null;
public ConnectionManager_Static(){ }
//as the staic method is updating static var i am synchonizing it
private static synchronized void getDatasource () throws NamingException, SQLException
if (ds == null){
ctx = new InitialContext();
ds = (DataSource)ctx.lookup("java:comp/env/jdbc/MySql");
//making getConnection() also static as it is not instance specific
public static Connection getConnection () throws NamingException, SQLException, Exception
Connection conn = null;
try{
if (ds == null) {getDatasource ();}
if (ds != null) {
conn = ds.getConnection();
}catch (Exception e){
throw new Exception("From ConnectionManager_Static",e);
return conn;
}//getConnection
}Singleton:
package common;
import java.sql.*;
import javax.sql.*;
import javax.naming.*;
public final class ConnectionManager_Singleton {
private static ConnectionManager_Singleton INSTANCE = null;
private DataSource datasource = null;
// Private constructor for singleton pattern
private ConnectionManager_Singleton() throws NamingException{
Context ctx = new InitialContext();
datasource = (DataSource)ctx.lookup("java:comp/env/jdbc/MySql");
//synchronized creator for multi-threading issues
//another if check to avoid multiple instantiation
private synchronized static void createInstance() throws NamingException{
if (INSTANCE == null) {
INSTANCE = new ConnectionManager_Singleton();
public static ConnectionManager_Singleton getInstance() throws NamingException {
if (INSTANCE == null) createInstance();
return INSTANCE;
public Connection getConnection() throws Exception
Connection con = null;
try{
con = datasource.getConnection();
}catch(Exception e){
throw new Exception("From connection manager singleton ", e);
return con;
}Sorry, It's becoming long.
Thanaks in advance,
Manisha -
Problems using connection pooling
I'm having problems configuring connection pooling in oc4j. Have specified my datasource/connection pool in my data-sources.xml. I always get the following error when I try to access it with an instance of OracleConnectionPoolDataSource within my apps. The app server dosen't seem to create the connections when started 'cos its not displayed within Oracle dba studio. Can anyone tell what I need to do pls.
regards!
dyzke
//-- error displayed
Exception in thread "main" java.sql.SQLException: Io exception: The Network Adap
ter could not establish the connection
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:168)
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:210)
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:323)
at oracle.jdbc.driver.OracleConnection.<init>(OracleConnection.java:260)
at oracle.jdbc.driver.OracleDriver.getConnectionInstance(OracleDriver.ja
va:365)
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:260)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at oracle.jdbc.pool.OracleDataSource.getConnection(OracleDataSource.java
:111)
// -- extract
<data-source
class="com.evermind.sql.DriverManagerDataSource"
name="MYDS"
location="jdbc/XXX"
xa-location="jdbc/xa/OracleXADS"
ejb-location="jdbc/OracleDS"
pooled-location="xxx/xxxx"
max-connections="10"
min-connections="3"
connection-driver="oracle.jdbc.driver.OracleDriver"
username="admin"
password="admin"
url="jdbc:oracle:thin:@localhost:xxx"
inactivity-timeout="30"
/>see my answer in the other newsgroup.
please don't cross post.
"M. Hammer" <[email protected]> wrote in message
news:[email protected]..
Hi,
We have problems using connection pooling in a WLS 5.1.x - Cluster. Is it
possible to use CP in such a cluster at all ? The problem is, connections
will be opened and never been closed. How can I configure a cluster forCP?
>
I have a WLS-Cluster with 2 instances and my webApp uses connectionpooling.
By the way I get a connection on Instance 1, Instance 2 gets a connection
also, but never releases it.
In my opinion, the reference to the connection in the partner-instancewill
be lost.
How do I have to configure my cluster to work well with that stuff ?
Thank a lot,
Markus.
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