JSP Overview

JSP (Java Server Pages) is a dynamic web page technology that allows embedding HTML, JavaScript, CSS, and Java code. JSP simplifies development by avoiding the direct output of HTML tags in Servlets.

JSP Quick Start

• Create a Maven web project with a specified structure and pom.xml file to include necessary dependencies for JSP.
• Create a JSP page named hello.jsp and write a mix of HTML tags and Java code within it.
• Test the JSP by running the server and visiting the JSP page, which displays content and prints a message to the console.

JSP Principles

JSP is fundamentally a Servlet. When a JSP page is accessed for the first time, Tomcat converts it into a Servlet, compiles it, and executes the resulting bytecode to serve requests. The JSP page essentially simplifies Servlet development.

JSP Scripting

JSP scripting allows defining Java code within a JSP page. However, it has drawbacks such as being difficult to write, read, debug, and it's not team-friendly. This has led to the gradual phase-out of JSP in favor of other technologies.

EL Expressions

Expression Language (EL) simplifies Java code in JSP pages. Its primary use is to retrieve data, usually from domain objects, to display on the page. The syntax for EL is straightforward: ${expression}.

JSTL Tags

JSTL (JSP Standard Tag Library) replaces Java code in JSP pages with tags, making it easier to write and understand, especially for front-end developers. The most commonly used JSTL tags are for conditional checks (if) and iterations (forEach).

• The if tag is used for conditional checks with the test attribute specifying the condition.
• The forEach tag is used for iterating over collections or ranges with attributes like items, var, varStatus, begin, end, and step.

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