Downloading and Installing NetBeans IDE

These instructions describe how to download and install NetBeans, a commonly used IDE for Java programming. Using an IDE means that you have all of the tools you need in one place (your "development environment") instead of having to organize things manually. Use the instructions in Step 2 to write a simple Java program called "Hello.java" and then compile and run it.

9. Developing and Deploying Web Application in NetBeans

9.3. Writing a Hello-World Servlet/JSP Web Application

Create a New Servlet/JSP Project

  1. From "File" menu ⇒ choose "New Project...".
  2. "Choose Project" ⇒ Under "Categories", choose "Java Web" ⇒ Under "Projects", choose "Web Application" ⇒ "Next".
  3. "Name and Location" ⇒ In "Project Name", enter "HelloServletJSP" ⇒ In "Project Location", select a suitable directory to save your works ⇒ Check "Set as Main Project" ⇒ Next.
  4. "Server and settings" ⇒ Choose your server, or "add" a new server ⇒ Next.
  5. "Frameworks" ⇒ Select none for pure servlet/JSP application ⇒ Finish.

Writing a Hello-World JSP

A JSP page called "index.jsp" is automatically created, which says "Hello world!". To execute this JSP, right-click on the project ⇒ "Run". The URL is http://localhost:8080/HelloServletJSP/index.jsp .

Writing a Hello-World Servlet

  1. Right-click on the project "HelloServletJSP" ⇒ New ⇒ Servlet.
  2. "Name and Location" ⇒ In "Class Name", enter "HelloServlet" ⇒ In "Package", enter "hello " ⇒ Next.
  3. "Configure Servlet Deployment" ⇒ In "Servlet Name", enter "HelloServletExample" ⇒ In "URL Pattern", enter "sayhello " ⇒ Finish.
  4. Enter the following codes for "HelloServlet.java": 
    package hello;
 
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
public class HelloServlet extends HttpServlet {
 
   @Override
   public void doGet(HttpServletRequest request, HttpServletResponse response)
           throws IOException, ServletException {
      // Set the response message's MIME type (in Content-Type response header)
      response.setContentType("text/html;charset=UTF-8");
      // Get an output Writer to write the response message over the network
      PrintWriter out = response.getWriter();
      // Write the response message (in an HTML page) to display "Hello, world!"
      try {
        out.println("<!DOCTYPE html>");
             out.println("<html>");
         out.println("<head><title>Hello Servlet</title></head>");
         out.println("<body><h1>Hello, World (from Java Servlet)!</h1></body>");
         out.println("</html>");
      } finally {
         out.close();  // Always close the output writer
      }
   }
}
  5. To execute the servlet: Right-click on the project ⇒ run ⇒ Change the URL to http://localhost:8080/HelloServletJSP/sayhello .

Generating a WAR-file for a Web Application

A WAR (Web Archive) file is basically a zip file for distributing web application in single file. You can use WinZip or WinRAR to inspect or unzip the war file.

To distribute the project as a war-file, right-click project ⇒ "Clean and Build". The war file is created in the "dist" directory. You can deploy the web application by dropping the war-file into Tomcat's "webapps" directory. Tomcat will automatically unzip the war-file and deploy the application upon startup.

Debugging Web Application

The most important reason for using IDE is to use the graphic debugger for debugging the program. You can set a breakpoint in your server-side Java codes, and "Debug" a web application, similar to a standalone application.