Java Server Pages - Basic Terms, Related Tags (Scriplets and Declarations)
Java (current. Jakarta) Server Pages is a framework used for web application development.
This post will discuss:
- Basic Terms
- JSP HTML Form Tags
Basic Terms
JSP, Servlets
As previously stated, JSP is used for web application programming. It can make use of the whole range of Java language functions, and runs separately from the directly client-facing components. (HTML, etc.)
JSP code is run in a Java servlet. Consequently, an implementation of a servlet must be made available to run JSP, such as Apache Tomcat. (Jetty, etc.)
HTTP
HTTP is a protocol, part of the application layer (OSI), wherein clients make requests to a server, which then delivers requested resources and content.
Requests that are routed from the client through HTTP can be transferred to a servlet.
URL
The URL can be understood as a web address, which points to a web resource on a network. If the address is prepended with the famous www, then it points to a resource on the World Wide Web.
The URL is a subset of the URI, which defines the location of a anything - in the context of the internet, it points to resource on a network. The URI includes the URL and the actual URI of a requested resource (defined through port number of a server, path of a resource, or query data).
The URL and data URI to this blog’s repo is: https://github.com/gonkmetrics/gonkmetrics.github.io/blob/main/index.md#resources
The URL defines the web address needed for a client to connect to a specific server through HTTP.
JSP HTML Form Tags
Implementing JSP into a web document can be done inline by inserting JSP code into the web document, delineating it with its own form tags.
<% %> Scriptlet tags delineate Java code to be executed at runtime (page load as well).
<h2>multiplication tables</h2>
<%
int count = 1;
while(count < 10){
for(int mult = 1;mult<=9;mult++){
if(mult % 2 == 1){
out.println("<p>"+count+"*"+mult+"="+(2*mult)+"</p>");
}
}
count++;
}
%>
<%! %> Declarative tags surround Java code that is declared once on runtime.
<%!
//%! declarative
//% script read
public int i = 10;
public String str = "hello";
int add(int n1, int n2){
return n1+ n2;
}
%>
<%
//declarations
int result = add(10,5);
out.println(result);
out.println(add(16, 14));
out.println(result);
%>
-gonkgonk