Ok - heres the article that actually goes through the Java Servlet code for this mini project. I've tried to make it as straightforward as possible, and have put particular tasks into seperate methods to help.

The Files

Before I start, you can download the files i'm using for this project here.

The Class Configuration

I have really gone to town with this Servlet and followed good techniques where possible. The following is the declaration code.

You will note the declaration of the Database, view, form names etc in advance - makes it easier to change when they are all in one place. Below this is the declaration of the 'Notes Objects' that we will be using. Finally the actual fields that we will be populating in the Notes Document are also declared - again to make it easier when I need to change anything.

As a note, in the version I tested on my Domino Server I did have the database names etc setup in the Servlet.properties file. However as the servlet for this site runs on a Tomcat/Jakarta Server at DominoDeveloper.net I have to setup the parameters differently - and I couldn't get it to work (I was rushed!) so instead I have 'hard coded' them.

The Methods

First of all - the important one is doPost(). This is where your Servlet kicks off (remembering what I said about doPost() and doGet() in a previous article).

The other methods: connectDomino(), createComment(), outputMessage() and recycleDomino() are 'service' methods for doPost(). In other words I have seperated out each function of the servlet into different methods which are then called from doPost(). I have done this to help you see what is going on, plus for good coding practice.

The methods: getServletInfo() and init() we do not need to concern ourselves with at this point.

doPost()

As previously mentioned, doPost() is where it all kicks off. It is the skeleton of the whole servlet and you will note the usual try,catch,finally structure for error handling that I have mentioned before.

At the start of the method, we firstly (apart from getting a PrintWriter handle) get the field values that were passed from our HTML Form.

This is very straightforward and we use the following syntax: String name=req.getParameter("name");. The key to this being the getParameter() method of the HttpServletRequest object (req).

The rest of doPost() is then very straightforward - after creating a Notes Thread using: NotesThread.sinitThread();, the following methods are then called in turn:

connectDomino()

The connectDomino() method is where all the Domino session, database etc connecting is done.

You can see over the first three lines the creation of the 'Notes Session' and then connecting to two notes databases (the variables dbname and dbnamelink were set earlier).

The first database (db) is where we are going to create a new Notes Document, and the second (dbLink) is a 'link database' I use to match up the article id passed from the HTML Form to the full article name.

The fourth and fifth lines are getting handles to the id lookup view in the Link Database and then the document that matches the id.

The final line of the code simply sets the String variable category to the article title for later use when creating the 'Comment' document.

When writing this article, I noticed that really I should check that the two databases have been found before proceeding - if they are not the error would be handled by the NotesException handler but it would be better practice to check them for null and return a more meaningful error.

You will perhaps also notice that once you get the hang of putting java together, dealing with exceptions etc the actual code part is not too dissimilar to LotusScript - so if you have used LotusScript you are most of the way there already.

createComment(type,name,subject,organisation,country,email,website,comment)

This method obviously creates the 'Comment' document and is very very simple - any LotusScript developer will recognise the syntax.

It is called from the doPost() method and passes all the parameters as String objects.

doc was declared as a NotesDocument in the global declarations (together with db), and db was 'attached' to the database within the connectDomino() method.

The main point to notice are the use of the "FIELD_" Strings that were declared in the global declarations.

outputMessage(name,out)

When everything has been done - the document created/saved etc - it is time to confirm to the end user that the task has been completed.

To do this we need to get a handle to the PrintWriter of the HttpServletResponse object. I have done this by passes the PrintWriter to the outputMessage() method using "out".

This is the code:

All I am doing is passing out basic HTML to the PrintWriter together with the variable 'name' - for personalisation.

recycleDomino()

The final part of the servlet is tidying everything up. We have to handle our own objects and 'recycle' them (using the recycle() method). We do this as follows:

You will note that I have been good and check the Notes Objects exist before calling the recycle() method. An error would occur if I didn't do this and the database name was incorrect etc. Also note that I have recycled in reverse order - ie session last and documents first.

Well thats the Java Servlet - hope you can follow it - im not the worlds most gifted technical writer - but I hope my examples do the 'real explanation'.

I also tend not to explain how to do something if I have in a previous article - so if you are learning from scratch I would recommend you read the previous Java Servlet articles first.