Tristan Van Poucke

Okay

I have no real performance issues, so I will leave it as it is.

Thanks for clearing that up for me.

Hi

I have a lot of persistence classes without private or public variables, ...
The methods only differ with the parameters passed to them.

So I thought I could save some memory making them all static methods.

Is this the way to go, or should I make them singletons or something?

Ok

I found the solution,

apparently the parameter name should be uppercase.

Although almost every search I did, I came across jsessionid in Lowercase.

Stupid mistake I guess

Thank you for the help.

Ok

I have made some progress.

It seems that the servlet recieves the jsession cookie from the applet correctly.
But it just ignores it.

Could this have something to do with tomcat?

Hmmm strange

I can't think of anything I do to change the default behaviour of the applet.

And it still uses another session...

Or could it be that the servlets, I call from the applet use a different session?

Ok

So when I do that i can add "jsessionid=..." to the urls of every servlet I call in the applet atleast for the GET methods.
How can I do this for PostMethod? This is what I have been trying, but it still uses a different session

PostMethod mPost = new PostMethod(url); mPost.setRequestHeader("Cookie", "jsessionid=" + sessionid );

Or is there a way of changing the session of the applet all together?

I need to pass the session to my applet.
Can I just put it in the code I use to call the applet?
Like this:
<Applet Code="UploaderPack.Uploader" archive="sImageUploader.jar;jsessionid=....

Or is that not safe enough?

Hi

I'm using a SessionListener to check if a user is online or not.
It basically keeps a List of all online users.
Too check if one is online or not I use "contains()".

If there were say a few 1000 users online it would take a while to perform "contains()".
That's why I thought of splitting up the lists in a few lists identified by the first 3 chars or so of the users id.


Is this the way to go, or are there other, better ways of doing this?

Tnx

I have been thinking about prepared statements, and I have a question
In following example(psuedo, well sortoff) I have a method executing a query.

In that method i prepare a statement:

public void prepExample() { PreparedStatement pstmt = con.prepareStatement("UPDATE EMPLOYEES SET SALARY = ? WHERE ID = ?"); pstmt.setBigDecimal(1, 153833.00) pstmt.setInt(2, 110592) pstmt.executeQuery(); }

If I call this method several times, will the statement be prepared over and over again?
Thus leaving me only with the security side of the benefits of prepared statements.

I found my mistake.

Apparently in some persistence method's I called other persistence methods.
That tried to get a connection from the connectionpool, and then close it.
The first persistence method will try to close that connection again.

Thanks for the help

Okay, I have done this.
I opened the connection and closed it once per page because when working without a connection pool this method seemed faster.
But now with the connectionpool I open it just before the query and close it afterward, because the connection does not really get opened and closed, this works
at about the same speed.

Only problem now is that I get a "connection is closed" SQLException on every method I try to close the connection

Okay, thank you very much.

Now I started with apache dbcp, but I don't understand completely.

I have a singleton class wich gets properties from a property file and uses them to open connections and store them in the connectionpool.

Like this (snipped code)
private GenericObjectPool connectionPool = new GenericObjectPool(null); private PoolingDataSource dataSource = null; private MySQLConnectionPool() { ConnectionFactory connectionFactory = new DriverManagerConnectionFactory(mDBURL, mDBUserName, mDBPassword); PoolableConnectionFactory poolableConnectionFactory = new PoolableConnectionFactory(connectionFactory,connectionPool,null,null,false,true); dataSource = new PoolingDataSource(connectionPool); }

Then I have this method "checkout" wich should give a connection to the user, this is being called whenever a user loads a page.

public Connection checkOut() { return (Connection) dataSource.getConnection(); }

But with my previous way of connecting, I closed the connection everytime the requested page was done loading.
I used a method "checkIn()", I don't understand how i could return the method in the connection pool...
Any suggestions?

Hello,

I started on writing my own connection pool, and I something is wrong.
If i test my site with testing software it runs ok. But if I combine that with me clicking on random links in the website, I start loosing connections
And eventually I run out of connection wich leads to null pointer exceptions.

this is my code:
static synchronized public MySQLConnectionPool getInstance() { if (mInstance == null) { // Must be the first call to the object mInstance = new MySQLConnectionPool(); } return mInstance; } private MySQLConnectionPool() { Connection tempConnection; String filePrefix = "/" + MySQLConnectionPool.class.getName().replace('.', '/'); InputStream propertyFile = getClass().getResourceAsStream(filePrefix + ".properties"); Properties poolProperties = new Properties(); try { poolProperties.load(propertyFile); } catch (Exception propertyException) { System.err.println("Error reading property file. " + filePrefix + ".properties is in the same directory with the ConnectionPool class."); return; } // First load the database driver by reading the driver from the properties file. try { String dbDriverName = poolProperties.getProperty("dbDriver"); mDBDriver = (Driver)Class.forName(dbDriverName).newInstance(); DriverManager.registerDriver(mDBDriver); // Now grab the remaining properties and create the pool of connections. mDBURL = poolProperties.getProperty("dbUrl"); mDBUserName = poolProperties.getProperty("dbUserName"); mDBPassword = poolProperties.getProperty("dbPassword"); mNumberOfConnections = Integer.parseInt(poolProperties.getProperty("numberOfConnections")); mConnections = new Vector(mNumberOfConnections); for ( int i = 0; i < mNumberOfConnections; i++ ) { tempConnection = (Connection) DriverManager.getConnection(mDBURL, mDBUserName, mDBPassword); mConnections.addElement(tempConnection); } } catch (Exception setupException) { System.err.println("Unable to setup JDBC connection pool. " + setupException); } } public Connection checkOutAndNewConnection() throws SQLException { Connection tempConnection = (Connection) DriverManager.getConnection(mDBURL, mDBUserName, mDBPassword); mConnections.addElement(tempConnection); return checkOut(); } public Connection checkOut() throws SQLException { System.out.println("********************** NUMBER OF CONNECTIONS LEFT:" + mConnections.size()); Connection dbConnection = null; if ( mConnections.size() > 0 ) { dbConnection = (Connection)mConnections.firstElement(); mConnections.removeElementAt(0); try { if (dbConnection.isClosed()) { dbConnection = checkOutAndNewConnection(); } else { dbConnection.getMetaData().getTableTypes(); } } catch (SQLException sqlE) { dbConnection = checkOut(); } } return dbConnection; } public void checkIn(Connection pConnection) { if ( pConnection != null ) { try { if ( !pConnection.isClosed() ) { mConnections.addElement(pConnection); } else { System.out.println("TIS EEEEN CLOSED8!!!!!!!!!!!!!!!"); } } catch (SQLException sqlE) { ; // Do nothing. Bad connection checked in. If counting checkouts reduce // the count here. } } } public synchronized void shutdown() { Connection tempConnection = null; ListIterator ConnectionIterator = mConnections.listIterator(); try { while ( ConnectionIterator.hasNext() ) { tempConnection = (Connection)ConnectionIterator.next(); tempConnection.close(); } ConnectionIterator = null; mConnections.removeAllElements(); DriverManager.deregisterDriver(mDBDriver); } catch (SQLException sqlE) { System.err.println("Unable to de-register the JDBC driver."); } mInstance = null; } }

Am I doing something wrong ?

Yesterday I tested my webapp with selenium ide.

I made selenium upload a picture to the server and a name and a description of it to the database, about 150 times.
What happened was, when I tested some pages myself while the selenium test was running. Those pages didn't load completely 90% of the times i refreshed.
What could my problem be?

I wouldn't think too much concurrent connections, since there was only 1 connection at a time.
But then again I do not have connection pooling yet.

I was running my webapp on my localhost tomcat 6(together with winamp and netbeans offcourse) and using a remote mysql database.
The selenium test was running on another computer in my network.

nice thank you.