Java Cookbook, 2nd Edition

Chapter 18. Network Clients II: Applets and Web Clients

Introduction

In Chapter 16, I discussed straightforward client applications that communicate over a socket. Chapter 17 covered simple server topics. Now we turn our attention to a variety of other client topics. First let’s look at Java-based web applet client programs. Applets are, as you probably know, small programs that run inside and under the control of a web browser. There’s a discussion of Applet versus JApplet and the Applet methods. Deploying an applet is no different from deploying a web page—you simply copy it into the web server directory—but you need an HTML page to invoke it (discussed in Recipe 18.1). We then discuss some additional client-side topics, such as loading a URL, that apply both to applets and to applications. Other books talk about servlets, which are programs similar to applets but designed to run inside the process of a web server. Applet deployment requires some considerations; see Recipe Recipe 23.6 for a means of ensuring that a user’s browser has a Java runtime compatible with your applet. Recipe 23.13 contains information on Java Web Start, which combines applet-like downloading with full application capabilities.

18.1. Embedding Java in a Web Page

Problem

You need to deploy a Java applet.

Solution

Use an <applet> tag in an HTML page.

Discussion

While this is not the place for a dissertation on the details of HTML, you should at least know that HTML is a tag-based textual language for writing ...