Java Servlet API instance tutorial
Java Servlet API instance tutorial
Java Servlet API is the standard extension of the Java programming language for the development of Java -based web applications.This tutorial will guide you to gradually understand the use of the Java Servlet API and how to create a simple service instance.If you need it, the Java code example is also provided to help you better understand.
1. Introduction to concept
Java Servlet is a server -side component independent of the platform that can expand web -based applications or services.Servlet receives requests from the client on the server and generates dynamic response data.
2. Environmental settings
Before starting to write service, you need to install the following environment:
-Java Development Kit (JDK): Used to write and run Java code.
-Apache Tomcat: An open source web server that supports service specifications.
3. Create a simple server
First, create a Java class and extend the HTTPSERVLET class in the class.This category will act as our Servlet.
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
public class MyServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<html><body>");
out.println("<h1>Hello, Servlet!</h1>");
out.println("</body></html>");
}
public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
// Implement the logic of post request here
}
}
4. Configure servicet
Before deploying applications, you need to configure the service in the web.xml file.The following is a web.xml file of an example:
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<servlet>
<servlet-name>MyServlet</servlet-name>
<servlet-class>MyServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>MyServlet</servlet-name>
<url-pattern>/myservlet</url-pattern>
</servlet-mapping>
</web-app>
5. Run Servlet
Compile the written class class into .class files and copy the file to the webapps directory of Tomcat.Then start the Tomcat server.Visit http:// localhost: 8080/MyServlet in the browser, and you will see the output "Hello, Servlet!".
This is just a simple Servlet example, of course, Servlet has more characteristics and usage.By learning Java Servlet API, you will be able to build a more complex and powerful web application.
I hope this Java Servlet API instance tutorial will help you!
