Chapter 17 - Deploying Java Applications on the Web1 Chapter 17 Deploying Java Applications on the Web

Chapter 17 - Deploying Java Applications on the Web2 Client-Server Model  Web applications are based on a form of distributed processing called client-server computing  Client requests an action and the server performs it  Internet is based on client-server model  Web browser requests a page  Web server returns the requested page to browser 1

Chapter 17 - Deploying Java Applications on the Web3 Typical Client-Server Exchange  Client computer issues a request to the Web server  Web server gathers necessary data, carries out the logic to fulfill the request, and returns the results to the client  Web applications is commonly handled with Java applets or HTML (Hyper text Markup Language) 1 17

Chapter 17 - Deploying Java Applications on the Web4 Typical Client-Server Exchange

Chapter 17 - Deploying Java Applications on the Web5 Creating the User Interface  Deciding on whether to use HTML or applets requires careful consideration  Applets may require resources the client doesn’t have  Applets can’t read/write files on the client  Applets take time to download  Thin client applications are those that minimize processing requirements on the client  HTML is used to create thin-client applications 1

Chapter 17 - Deploying Java Applications on the Web6 Using HTML to Create an Input Form  Action attribute of the tag specified the Uniform Resource Locater (URL) of the file on the web server  HTTP (Hypertext Transfer Protocol) specifies transfer mechanisms  8080 specifies the communications port  Client and server listen for request on this port 1

Chapter 17 - Deploying Java Applications on the Web7 Java Servlets  Server-side applets  Java programs residing on a web server that can be run by a web server, like Apache Tomcat  Why Servlets?  Persistent maintain services for multiple clients  Fast Loaded only once  Platform-independent in Java  Extensible EJBs  Secure run through a web server  Methods: doPost() and doGet() 1

Chapter 17 - Deploying Java Applications on the Web8

9 Using JavaScript to Validate Input  JavaScript is used to validate form data on the client  Uses the tags  If an error occurs an alert message is displayed 1 17

Chapter 17 - Deploying Java Applications on the Web10 Java Server Pages  Java Server Pages (JSP) is an HTML file embedded with Java code  JSPs can do anything a servlet can do  All JSP files have a.jsp extension  JSP tags are enclosed in  Used to enclose executable Java statements 1

Chapter 17 - Deploying Java Applications on the Web11 Exploring Other Technologies  Active Server Pages (ASP)  PHP  Dynamic HTML (DHTML)  Extensible Markup Language (XML)  XHTML (Extensible HTML)  Flash  Perl and CGI 1

Chapter 17 - Deploying Java Applications on the Web12 Demo