How to build a Web Application Using Java
Java is one of the most use program languages for developing moral force web applications. A web application is computer software that utilizes the web browser and technologies to perform tasks over the internet. A network application is deployed on a web server .
Java provides some technologies like Servlet and JSP that allow us to develop and deploy a network lotion on a server well. It besides provides some frameworks such as spring, Spring Boot that simplify the work and provide an efficient way to develop a network application. They reduce the campaign of the developer .
We can create a web site using static HTML pages and style them using CSS, but we need server-side engineering when we want to create a active web site .
In this section, we will see how to create a web site using Java Servlets and HTML. Further, we will see how these technologies are utilitarian for developing a web application.
In this department, we have included :
- What is a Web Application
- Web Server and Client
- HTML and HTTP
- What is URL
- What is Servlet
- Why Servlets are Useful for Developing a Web Application
- First Web Application Using Java Servlet
Let ‘s understand the components of a web application :
What is a Web Application
Web Server and Client
The world wide web waiter is a march that handles the node ‘s request and responds. It processes the request made by the customer by using the refer protocols. The main routine of the webserver is to store the request and react to them with world wide web pages. It is a medium between client and server. For model, Apache is a leading webserver .
A node is a software that allows users to request and assist them in communicating with the server. The world wide web browsers are the clients in a web application ; some lead clients are Google Chrome, Firefox, Safari, Internet Explorer, etc .
HTML and HTTP
The HTML stands for HyperText Markup Language ; it is a park speech for Web Server and Web Client communication. Since both the web server and vane client are two different software components of the network, we need a language that communicates between them .
The HTTP stands for HyperText Transfer Protocol ; it is a communication protocol between the node and the server. It runs on top of the TCP/IP protocol .
Some of the built-in components of an HTTP Request are as comply :
HTTP Method: The HTTP method defines an natural process to be performed ; normally, they are GET, POST, PUT, etc .
URL: URL is a web cover that is defined while developing a web application. It is used to access a web page .
Form Parameters: The form parameter is just like an argument in a Java method acting. It is passed to provide the details such as user, password details on a login page .
What is URL
URL stands for Universal Resource Locator used to locate the waiter and resource. It is an cover of a web page. Every vane page on a project must have a unique name .
A URL looks like as follows :
http or https: It is the starting point of the URL that specifies the protocol to be used for communication .
Localhost: The localhost is the address of the server. When we run our application locally, it is called localhost ; if we deployed our plan over the web, then it is accessed by using the domain mention like “ Flickroom.com ”. The domain name maps the server to IP addresses .
8080: This is the port number for the local anesthetic waiter ; it is optional and may differ in different machines. If we do not manually type the interface number in the URL, then by default option, the request goes to the default port of the protocol. normally, the port no between 0 to 1023 are reserved for some well-known services such as HTTP, HTTPS, FTP, etc .
We have discussed all the major components of a world wide web application. Let ‘s move towards our main motivation How to build a web application in Java .
first, understand servlet :
What is Servlet
A Servlet is a java program that runs within a web server ; it receives the requests and responds to them using refer protocols ( Usually HTTP ). The Servlets are capable adequate to respond to any type of request ; they are normally used to make the application functional .
We can create a inactive web site using only HTML and CSS, but when it comes to dynamic, we need a server-side scheduling language. For these applications, Java provides Servlet engineering, which contains HTTP-specific servlet classes .
The javax.servlet and javax.servlet.http packages contain interfaces and classes for creating servlets. All servlets should implement the Servlet interface, which defines life-cycle methods. To implement a generic servicing, we can use the GenericServlet course by extending it. It provides doGet and doPost methods to handle HTTP-specific services .
Why are the Servlets Useful?
network servers are capable adequate to serve static HTML requests, but they do n’t know how to deal with moral force requests and databases. so, we need a speech for moral force subject ; these languages are PHP, Python, Java, Ruby on Rails, etc. In Java, there are two technologies Servlet and JSPs, that deals with moral force message and database. Java besides provides frameworks such as jump, Spring Boot, Hibernate, and Struts to use the servlet and JSP easily .
The Servlets and JSPs are server-side technologies that extend the functionality of a vane waiter. They support dynamic response and data doggedness. We can easily create a network application using these technologies .
Let ‘s create our first web applications :
First Web Application Using Java Servlet
To create a web application, we need the follow tools :
IDE ( Eclipse or Netbeans )
Database ( Oracle or Mysql )
Server ( Tomcat )
Before Creating any vane application, ensure that all of the above tools are by rights installed on your arrangement .
now, follow the downstairs steps to develop a web application :
Step1: Open Eclipse Create a Dynamic Web Project
Open the Eclipse IDE, navigate to File-> New-> Dynamic Web Project.
If the dynamic web stick out is not listed in your IDE, then go to the other option and search for it. Click on it to continue .
Step2: Provide Project Name
Read more: How to Change Your IP Address
now, enter the plan name and chatter Next to continue .
Follow the motivate and tick the beget web.xml deployment form .
now, our project is cook ; the project structure will look as follows :
Step3: Create a Servlet
now, create a servlet by right-clicking on the Java Resources/src booklet. To create a servlet right click on the src folder and navigate to the New-> Servlet menu. here, provide the Servlet name :
Click on the Finish button. It will create a TestServlet as specified. You can choose any of your Servlet names .
Step4: Add the Servlet Jar file
We can see our Servlet is displaying lots of errors it is because we have not added the servlet-api jolt file yet. To add the jolt file, right-click on the project and select the shape option by navigating to Build Path-> Configure Build Path option. now, click on the Add External JARs choice .
navigate to the directory where you have installed your server and select the servlet-api.jar file .
Click Open to continue .
now select Apply and Close choice. It will add the jar file to our stick out .
Step5: Create a HTML or JSP file
nowadays, our inaugural web application is about quick. We can create HTML pages that we want to display on our web site .
To create an HTML page, right-click on the WebContent booklet and select the New HTML file choice from the New-> HTML File menu with the name index.html .
We have created the follwing HTML file :
Step6: Map the File
now, map this file in the web.xml file. The web.xml is a deployment descriptor for the Servlet applications. Since, Servlet 3.0, we can use annotations rather of the deployment form .
To map a servlet, we have to provide the servlet details such as Servlet diagnose and class. Consider the below code :
We can besides define our welcome file ; a welcome file is the first file of the project that initiates the project, besides known as Home. We can define multiple welcome files .
Consider the below code :
From the above code, we can see by default the servlet defines several welcome files. If you want to use any file other than the number files, you can define that here .
now, our first web application is fix .
Step7: Run the Application
To run the lotion, right-click on the project and run it on the server by selecting Run-> Run on Server choice .
It will take some time to load the application .
We can besides test it on other browsers by entering the URL .
now, we can design this by adding more world wide web pages and styles .
In the above screen, we have updated our index.html file as follows :
Add the persona charge into WebContent booklet.
In this incision, we have discussed how to create a vane application using Java Servlets. Java facilitates with other frameworks such as spring and Spring Boot that helps us to develop vane applications easily. These frameworks reduce the effort of the developer .
Check out our spring and Spring Boot tutorials .