asked on

How to convert these java codes (for a feedback) to javabean?

Can anyone please help me to convert these java codes (for feedback) to javabean (using the MVC Model-View-Controller pattern design)?

<%

//instantiate variables
Connection con = null;
Statement stmt = null;
Statement stmt2 = null;
ResultSet rs = null;
String queryString;
int newInBoxMsg = 0;
int newSentMsg = 0;
int newSavedMsg = 0;
int newTrashCanMsg = 0;
String currentUserID = 1+"";
String adminID = 1+""; //change this ID to your adminID in the db

try
{
//Load the JDBC driver
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver").newInstance();

//Get the connection getConnection("access driver", "userID", "password")
con = DriverManager.getConnection("jdbc:odbc:FREN_DB","","");
stmt = con.createStatement();

//sql statements: create, update, query
Calendar cl = Calendar.getInstance();
%>

<%
if(request.getMethod()=="POST"){

int y = stmt.executeUpdate("INSERT into Feedback(`whom`, `msg`, `date`)"
+" values ('"+currentUserID+"', '"+request.getParameter("date")+"', '"
+request.getParameter("msg")+"')");

int x = stmt.executeUpdate("INSERT into MailBox(`whom`, `who`, `mailheader`, `mailbody`, `date`)"
+" values ('"+adminID+"', '"+currentUserID+"', 'Feedback', 'We have received your feedback and we will respond to you as soon as possible', '"+request.getParameter("date")+"')");

out.println("Feedback Sent!");
}
else {
%>

<form name="compose" method="POST" action="Feedback.jsp">
<input name="date" type="hidden" value="<% out.println(cl.get(cl.DAY_OF_MONTH)+"/"+cl.get(cl.MONTH)+"/"+cl.get(cl.YEAR)); %>" maxlength="20">
<p>Your Feedback</p>
<p>
<textarea name="msg" cols="50" rows="10"></textarea>
</p>
<p>
<input type="submit" name="Submit" value="Submit">
</p>
</form>

<%

}

}catch(Exception e) {
System.out.println(e);
}

%>

bloodredsun

Rather than going to struts, the simplest MVC method for this would be to use a servlet to get the data from the db (controller-ish), populate a javabean (Model), put the javabean in the request, and then use RequestDispatcher to forward to a jsp (View).

ashok3sep

Please read the following link to understand what is behind the MVC architecture
and you would better have a clear Idea.

http://www.oracle.com/technology/sample_code/tech/java/j2ee/jintdemo/tutorials/Struts.html

regards,

Freedom.

TimYates

I agree with bloodredsun...

Using a framework would be overkill if this is the only thing you have to convert... But just putting code in a class, then calling that class from the JSP does not make it MVC...it just makes it a bit neater...

You will need to follow bloodredsun's advice to get "true MVC"

The main issue I can see with your code is that someone could potentially perform an SQL Injecttion attack on your database (as you aren't using PreparedStatements), and you should be using a connection pool to get your connection (as this will speed things up)

Tim

dr0zaxx

ASKER

Hmm.. can anyone please direct convert the codes for me here?

bloodredsun

I would also recommend using a DataSource and PreparedStatements for your database interactions.

bloodredsun

Ha! Sorry Tim didn't refresh before the PS comment.

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bloodredsun

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bloodredsun

It would actually be a little better to replace the date value created in the scriplet in feedback_form.jsp with data from a bean that is created in the servlet and passed to the jsp in the request. In this case, the bean could repersent part of your model and also function as a DTO (Data Transfer Object) which is always good coding practise.

e.g.
in servlet
------------
Calendar cl = Calendar.getInstance();
FeedbackBean = myFeedbackBean = new FeedbackBean() ;
myFeedbackBean.setDate( cl.DAY_OF_MONTH + cl.MONTH + cl.YEAR ) ;
//set in request
request.setAttribute( "feedbackBean" , myFeedbackBean ) ;

in jsp, using JSTL to output the bean's value
---------
<input name="date" type="hidden" value="<c:out value='${requestScope.feedbackBean.date}' />" maxlength="20">

This creates the possiblity of passing the bean throughout your application so creating a model of your data.

bloodredsun

And you'll need to do a null check before the servlet line
>>if (request.getParameter("action").equals("feedback")){

as otherwise it will throw a nullPointerException.