Two essential technologies for creating web applications with the Java programming language are Java Servlets and JSP (JavaServer Pages). While JSP is a technique for creating templates that enables programmers to create HTML content dynamically, Servlets are server-side components that manage HTTP requests and produce HTTP responses. Here is a summary of how to create web apps using JSP and Java Servlets.
Creating a Servlet:
In order to process HTTP requests, a Servlet is a Java class that extends the HttpServlet class and overrides the doGet or doPost function. Servlets have access to database connections, session data, and request parameters.
Configuring a Servlet:
The web.xml file or the more recent Servlet 3.0 annotation-based configuration are used to configure servlets. The configuration specifies any initialization settings and the Servlet’s URL pattern.
Creating a JSP:
A template file called a JSP is made up of both HTML and Java code. Using user input or database data, JSPs can create dynamic content.
Embedding Java code in JSP:
Scriptlets, which are encased in %%> tags, can be used to embed Java code in JSP. Java declarations and expressions may also be used in JSPs.
Using JSP tags:
JSP tags are predefined elements that can be used to create HTML output or do out operations like iterations or database queries. Standard tags and Custom tags are the two categories into which JSP tags can be separated.
JSP programming is made easier by the JSTL (JavaServer Pages Standard Tag Library), which is a collection of unique tags. Iterative operations, string manipulation, and conditional code execution are all possible using JSTL tags.
Using MVC pattern:
Web applications frequently use the Model-View-Controller (MVC) pattern as their architecture. Servlets, JSPs, and JavaBeans can all function as models, controllers, and views, respectively.
Error pages, which are HTML or JSP files that are presented to the user in the event of an error, can be used by Servlets and JSPs to handle errors. The more recent Servlet 3.0 annotation-based setup or the web.xml file can be used to configure error pages.
In conclusion, Java Servlets and JSP are important web application development tools for Java programmers. Developers may create robust and dynamic web applications by developing Servlets and JSPs, configuring them, incorporating Java code, utilizing tags and libraries, employing the MVC design, and managing errors.