A servlet is a server-side component of Java web applications that processes requests and generates dynamic responses. Java Server Pages (JSP) is a technology for creating dynamic web pages in Java.

Steps for conversion

To convert a basic servlet to JSP, we will need to follow the steps below:

• Identify the servlet functionality: Understand the purpose and functionality of the existing servlet. Take note of any request parameters, session attributes, and HTML generation logic within the servlet.

• Create a JSP file: Create a new JSP file with a .jsp extension. This file will replace the HTML generation logic in the servlet.

• Copy HTML markup: Copy any static HTML markup from the servlet’s doGet() or doPost() method into the JSP file. This includes any HTML tags, forms, tables, etc.

• Replace Java code: Replace any Java code in the servlet that generates dynamic content with JSP code. We can embed Java code within <% %> tags in the JSP file.

Example of servlet to JSP conversion

For example, if we have the following Java code in the servlet:

We can convert it to JSP code as follows:

• Use JSP expression language: Instead of concatenating Java variables with HTML strings, we can use JSP Expression Language (EL) to insert dynamic values into the HTML markup directly. EL uses the ${} syntax.

For example, instead of:

We can use EL as follows:

• Remove servlet code: Once we have moved all the necessary code to the JSP file, we’ll remove the corresponding Java code from the servlet. We can delete or comment on the lines that are no longer needed.

• Forward or redirect requests: In the servlet, we might have used RequestDispatcher to forward or redirect requests. We can achieve the same functionality in JSP using <jsp:forward> or <jsp:include> tags.

For example, instead of:

We can use JSP forward tag in the servlet or directly specify the target JSP file for redirection.

For example:

• Deploy the JSP file: Deploy the JSP file and any necessary configuration files to our web server.

Following the steps above, we can convert a basic servlet to a JSP file, separating the dynamic content generation from the servlet logic.