Copyright © 2002 ProsoftTraining. All rights reserved. Java Servlets.

Copyright © 2002 ProsoftTraining. All rights reserved.

Java Servlets


Lesson 1:Introduction

to Java Servlets

Objectives

• Describe the differences between servlets and other Web application technologies

• Explain the difference between the GET and POST methods of making an HTTP request

• Create a simple servlet using GET• Create a simple servlet using POST• Define a simple deployment descriptor

Introductionto Web Applications

• Web application technologies– Common Gateway Interface (CGI)– Server extensions– Server-side scripting– JavaServer Pages– Java servlets

HypertextTransfer Protocol

• The GET method• The POST method• Additional methods

Writing aSimple Servlet

javax.servlet.Servlet

GenericServlet HttpServlet

Respondingto Form Data

• FormServlet• getParameter method• Using the POST method

DeploymentDescriptors

• XML files conforming to Sun Microsystems DTD– Describes servlets contained within a Web

application

Summary

Describe the differences between servlets and other Web application technologies

Explain the difference between the GET and POST methods of making an HTTP request

Create a simple servlet using GET Create a simple servlet using POST Define a simple deployment descriptor


Lesson 2:The Servlet Life Cycle

Objectives

• Describe the servlet life cycle• Create init and destroy methods• Retrieve servlet initialization parameters• Use the SingleThreadModel interface• Retrieve CGI environment variables• Retrieve and use the ServletContext object• Use temporary files

TheMultithreaded Model

• Servlets typically operate in a multithreaded environment– The Web server usually instantiates only

one instance of a servlet to serve all clients• Deployment descriptors and the multithreaded

model

TheSingle Thread Model

• The Web server guarantees that no two threads will ever operate concurrently on the same servlet instance

• To designate servlets to use the single thread model, implement the following interface:– javax.servlet.SingleThreadModel

The initand destroy Methods

• The init method– Initialization parameters and the

deployment descriptor• The destroy method

CGIEnvironment Variables

• AUTH_TYPE• CONTENT_LENGTH• CONTENT_TYPE• HTTP_ACCEPT• HTTP_REFERER• HTTP_USER_AGENT• PATH_INFO• PATH_TRANSLATED• QUERY_STRING

• REMOTE_ADDR• REMOTE_HOST• REMOTE_USER• REQUEST_METHOD• SCRIPT_NAME• SERVER_NAME• SERVER_PROTOCOL• SERVER_PORT

The ServletContext

• Methods for obtaining server information• Using temporary files

Summary

Describe the servlet life cycle Create init and destroy methods Retrieve servlet initialization parameters Use the SingleThreadModel interface Retrieve CGI environment variables Retrieve and use the ServletContext object Use temporary files


Lesson 3:Responding to a Request

Objectives

• Use client-side caching• Use client pull to update a client• Redirect the client to another URL• Use persistent connections• Use response status codes• Return a file to a client• Dynamically generate images

Controllingthe Client

• Using client-side caching• Using client pull• Redirecting the client

PersistentConnections

public class PersistentConnection extends HttpServlet{

public void doGet(HttpServletRequest req,HttpServletResponse resp)throws ServletException, IOException

{resp.setBufferSize(32 * 1024);resp.setContentType("text/html");PrintWriter out = resp.getWriter();

// Generate a response}

}

Status Codes

• Status code constants• sendError method used to set status code

Multimedia Content

• Returning a file• Dynamically generating images

Summary

Use client-side caching Use client pull to update a client Redirect the client to another URL Use persistent connections Use response status codes Return a file to a client Dynamically generate images


Lesson 4:Servlet Sessions

Objectives

• Track a session using hidden form fields• Track a session using URL rewriting• Track a session using cookies

HiddenForm Fields

<INPUT TYPE="HIDDEN" NAME="SID" VALUE="1234567890">

Hidden form field named "SID" with an assigned value of

"1234567890"

URLRewriting

• Servlets can build URLS that add information in the form of additional path information

Cookies

• Small pieces of information transmitted from a Web server to a Web browser

• Represented in Java using the Cookie class

Summary

Track a session using hidden form fields Track a session using URL rewriting Track a session using cookies


Lesson 5:Authentication

and Security

Objectives

• Authenticate a user using HTTP-based authentication

• Authenticate a user using a form• Use Secure Sockets Layer to improve security

HTTP-BasedAuthentication

• Users• The deployment descriptor• Servlets and authentication

FormAuthentication

• Requires modification of the deployment descriptor– The login-config element must be

modified to indicate that form authentication is to be used and to provide the URL for a login page and login error page

Summary

Authenticate a user using HTTP-based authentication

Authenticate a user using a form Use Secure Sockets Layer to improve security


Lesson 6:Inter-Servlet

Communication

Objectives

• Share data with another servlet• Handle a single request using multiple

servlets

Sharing Data

• Data-sharing methods of the ServletContext interface

• Sharing data with another ServletContext

Dispatchingto Another Servlet

• The forward method• The include method

Summary

Share data with another servlet Handle a single request using multiple

servlets


Lesson 7:Building EnterpriseWeb Applications

Objectives

• Use JNDI to look up EJBs, resource factories and environment entries

• Write servlets for use in a distributed environment

• Use JavaMail to send e-mail

Java Servlets and JNDI

• Referencing EJBs• Referencing resource factories• Referencing environment entries

Clusteringand Java Servlets

• Clustering styles• Developing distributable servlets

JavaMail

• Add-on API that creates a full-fledged POP/iMAP client– Session class– getDefaultInstance static method

Summary

Use JNDI to look up EJBs, resource factories and environment entries

Write servlets for use in a distributed environment

Use JavaMail to send e-mail


Lesson 8:Internationalization

Objectives

• Use the Unicode escape sequence to specify special Latin characters

• Use alternative character sets to generate a non-Latin character response

The LatinCharacter Set

• Non-English Latin characters• Languages and language codes

Non-LatinCharacter Sets

• Arabic• Chinese• Japanese• Korean• Russian

Summary

Use the Unicode escape sequence to specify special Latin characters

Use alternative character sets to generate a non-Latin character response

Java Servlets

Introduction to Java Servlets The Servlet Life Cycle Responding to a Request Servlet Sessions Authentication and Security Inter-Servlet Communication Building Enterprise Web Applications Internationalization

Copyright © 2002 ProsoftTraining. All rights reserved. Java Servlets.

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