There are two sorts of net apps that builders can create in Java: static and dynamic purposes. Static net apps render the identical precise content material every time a shopper asks for it, whereas dynamic net apps permit for specific content material to be created for every net web page. This may be helpful in circumstances the place you prefer to completely different customers to view completely different data.

Learn: Greatest Kanban Instruments for Builders

A static web page is normally an html file (or a jsp file). Nevertheless, in the case of dynamic net pages, net builders want a servlet to create a web page every time a consumer makes a request to the server.

This programming tutorial covers how one can construct a easy dynamic net app to your server utilizing Java. Additionally, you will want to make use of a server reminiscent of Tomcat or Glassfish as nicely. We will likely be utilizing the Tomcat server for the instance on this tutorial.

What’s the Customary Listing Construction in Java?

When creating net purposes in Java, it is very important comply with the J2EE listing construction. This can make sure that the applying server is aware of the place to search out the information it wants. Right here is the listing hierarchy it is best to comply with when making a Java net app:

MyWebApp/
  index.jsp
  index.html
  pictures/
  audios/
  WEB-INF
       |
       |__web.xml
       |
       |__ courses/
       |
       |__ lib/

Within the root listing of your net app, you could have file referred to as index.html/ index.jsp information, in addition to the WEB-INF listing. Outdoors the WEB-INF listing, builders can even embrace useful resource folders to carry issues like pictures or audio information. These contents are robotically downloaded to a consumer’s shopper after they request the default web page of the net utility.

In your WEB-INF listing, you’ll find the net.xml file and two directories: courses and lib. The net.xml file is the net deployment descriptor and it maps URLs to a given useful resource.

The subsequent part will focus on how one can use net.xml file. The courses listing holds your servlets, whereas the lib listing incorporates the JAR library information required to your utility.

You possibly can be taught extra about working with JAR information in our tutorial: The way to Work with Java JAR Recordsdata.

The contents exterior this listing aren’t immediately accessed by the shopper.

What’s a Net Deployment Descriptor in Java?

As talked about earlier, the net deployment descriptor (net.xml) file tells your container which servlet goes to deal with a request from a given URL. To create the net.xml file, start by creating the foundation aspect . With the intention to outline a servlet and its mapping, you want a root aspect referred to as .

<web-app>
   <servlet>
       <servlet-name>Net-Software</servlet-name>
       <servlet-class>com.developer.MyServlet</servlet-class>
   </servlet>
   <servlet-mapping>
       <servlet-name>Net-Software</servlet-name>
       <url-pattern>/webapi/*</url-pattern> <!-- the * means "all"-->
   </servlet-mapping>
</web-app>

$ jar cvf MyWebApp.battle  *