JSP Basic syntax -Declarations Scriptlets

In this post I would like to explain basic syntax of JSP
Lets start with the Scriptlet
Following is the syntax of scriptlet:

<%  code goes here…..%>

On other hand code rendered inside <% %> these tags considered as jsp code; and compiled as JSP code
We have XML equivalent of the above syntax ;it would be looks something like this:

 
   Code goes here……

Now let’s write a simple jsp file:

<% 
int i=2;
int k=3;
int j=k+i;
out.println("sum of i and j is:"+j);
%>

The output would be something like this:
Sum of I and j is:5

 Nothing special in it; now consider the xml syntax we can run the above code like this:

 int i=2;
int k=3;
int j=k+i;
out.println("sum of i and j is:"+j);

In jsp there is a shortcut for out.println() method .consider the following example

<% 
int i=2;
int k=3;
int j=k+i;
%>
Sum of I an j is:<%=k%>

Ie <%= variable %> this way we can print a variable inside a jsp file. When compared to out.println() method it is more convenient . Before we conclude this I would like to explore one more tag which is very handy .

JSP Declaration


Syntax for jsp declaration something like this:

<%! Declaration goes here ….%>

Declaration tags is used to declare public method so that those methods are available to all other script bloc consider an example.

<%!
public int add(int a,int b){
 return a+b;
}

%>
<%=add(5,6)%>
<%=add(20,3)%>

In this way we can call add() method in anywhere in the page.