Overview of On-Line Version We hope you enjoy this PDF version of the first edition of the international bestseller Core Servlets and JavaServer Pages (courtesy of Sun Microsystems Press). If you are interested in the second edition of the book, it is available through most major on-line and brick-and-mortar bookstores. See http://www.coreservlets.com for details. Interested in the sequel? Check out More Servlets and JavaServer Pages at http://www.moreservlets.com . Looking for servlet and JSP short courses taught by the author? Visit http://courses.coreservlets.com. Available on-site at your company or at public venues. v Chapter © Prentice Hall and Sun Microsystems. Personal use only; do not redistribute. Second edition of this book: http://www.coreservlets.com. Sequel: http://www.moreservlets.com. Servlet and JSP training courses: http://courses.coreservlets.com. Acknowledgments xix About the Author xx Introduction xxi Real Code for Real Programmers xxii How This Book Is Organized xxiii Conventions xxvii About the Web Site xxvii Part 1 Servlets 2.1 and 2.2 2 Chapter 1 Overview of Servlets and JavaServer Pages 4 1.1 Servlets 5 1.2 The Advantages of Servlets Over “Traditional” CGI 7 Efficient 7 Convenient 7 Table of Contents vi Contents © Prentice Hall and Sun Microsystems. Personal use only; do not redistribute. Powerful 8 Portable 8 Secure 8 Inexpensive 9 1.3 JavaServer Pages 9 1.4 The Advantages of JSP 10 Versus Active Server Pages (ASP) 10 Versus PHP 10 Versus Pure Servlets 11 Versus Server-Side Includes (SSI) 11 Versus JavaScript 11 Versus Static HTML 12 1.5 Installation and Setup 12 Obtain Servlet and JSP Software 12 Bookmark or Install the Servlet and JSP API Documentation 14 Identify the Classes to the Java Compiler 14 Package the Classes 15 Configure the Server 16 Start the Server 17 Compile and Install Your Servlets 18 Chapter 2 First Servlets 20 2.1 Basic Servlet Structure 21 2.2 A Simple Servlet Generating Plain Text 23 Compiling and Installing the Servlet 24 Invoking the Servlet 25 2.3 A Servlet That Generates HTML 26 2.4 Packaging Servlets 27 Creating Servlets in Packages 28 Compiling Servlets in Packages 29 Invoking Servlets in Packages 30 2.5 Simple HTML-Building Utilities 31 2.6 The Servlet Life Cycle 34 The init Method 34 The service Method 36 Contents vii © Prentice Hall and Sun Microsystems. 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The doGet, doPost, and doXxx Methods 37 The SingleThreadModel Interface 38 The destroy Method 38 2.7 An Example Using Initialization Parameters 39 2.8 An Example Using Servlet Initialization and Page Modification Dates 44 2.9 Debugging Servlets 50 2.10 WebClient: Talking to Web Servers Interactively 52 WebClient 52 HttpClient 55 NetworkClient 57 SocketUtil 59 CloseableFrame 60 LabeledTextField 61 Interruptible 63 Chapter 3 Handling the Client Request: Form Data 64 3.1 The Role of Form Data 65 3.2 Reading Form Data from Servlets 66 3.3 Example: Reading Three Explicit Parameters 67 3.4 Example: Reading All Parameters 70 3.5 A Resumé Posting Service 74 3.6 Filtering Strings for HTML-Specific Characters 87 Code for Filtering 88 Example 89 Chapter 4 Handling the Client Request: HTTP Request Headers 92 4.1 Reading Request Headers from Servlets 94 4.2 Printing All Headers 96 4.3 HTTP 1.1 Request Headers 98 4.4 Sending Compressed Web Pages 104 4.5 Restricting Access to Web Pages 107 viii Contents © Prentice Hall and Sun Microsystems. 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Chapter 5 Accessing the Standard CGI Variables 114 5.1 Servlet Equivalent of CGI Variables 116 5.2 A Servlet That Shows the CGI Variables 119 Chapter 6 Generating the Server Response: HTTP Status Codes 122 6.1 Specifying Status Codes 124 6.2 HTTP 1.1 Status Codes and Their Purpose 126 6.3 A Front End to Various Search Engines 135 Chapter 7 Generating the Server Response: HTTP Response Headers 142 7.1 Setting Response Headers from Servlets 143 7.2 HTTP 1.1 Response Headers and Their Meaning 145 7.3 Persistent Servlet State and Auto-Reloading Pages 154 7.4 Using Persistent HTTP Connections 163 7.5 Using Servlets to Generate GIF Images 168 Chapter 8 Handling Cookies 178 8.1 Benefits of Cookies 179 Identifying a User During an E-commerce Session 180 Avoiding Username and Password 180 Customizing a Site 180 Focusing Advertising 181 8.2 Some Problems with Cookies 181 8.3 The Servlet Cookie API 183 Creating Cookies 183 Cookie Attributes 183 Placing Cookies in the Response Headers 186 Reading Cookies from the Client 186 8.4 Examples of Setting and Reading Cookies 186 Contents ix © Prentice Hall and Sun Microsystems. Personal use only; do not redistribute. 8.5 Basic Cookie Utilities 190 Finding Cookies with Specified Names 190 Creating Long-Lived Cookies 191 8.6 A Customized Search Engine Interface 191 Chapter 9 Session Tracking 198 9.1 The Need for Session Tracking 199 Cookies 200 URL-Rewriting 200 Hidden Form Fields 201 Session Tracking in Servlets 201 9.2 The Session Tracking API 201 Looking Up the HttpSession Object Associated with the Current Request 202 Looking Up Information Associated with a Session 202 Associating Information with a Session 205 Terminating Sessions 206 Encoding URLs Sent to the Client 206 9.3 A Servlet Showing Per-Client Access Counts 207 9.4 An On-Line Store Using a Shopping Cart and Session Tracking 209 Building the Front End 210 Handling the Orders 215 Behind the Scenes: Implementing the Shopping Cart and Catalog Items 220 Part 2 JavaServer Pages 228 Chapter 10 JSP Scripting Elements 230 10.1 Scripting Elements 233 Template Text 234 10.2 JSP Expressions 234 xContents © Prentice Hall and Sun Microsystems. 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Predefined Variables 234 XML Syntax for Expressions 235 Using Expressions as Attribute Values 235 Example 236 10.3 JSP Scriptlets 238 Using Scriptlets to Make Parts of the JSP File Conditional 241 Special Scriptlet Syntax 242 10.4 JSP Declarations 242 Special Declaration Syntax 244 10.5 Predefined Variables 244 Chapter 11 The JSP page Directive: Structuring Generated Servlets 246 11.1 The import Attribute 248 Directories for Custom Classes 248 Example 249 11.2 The contentType Attribute 251 Generating Plain Text Documents 252 Generating Excel Spreadsheets 254 11.3 The isThreadSafe Attribute 258 11.4 The session Attribute 259 11.5 The buffer Attribute 259 11.6 The autoflush Attribute 260 11.7 The extends Attribute 260 11.8 The info Attribute 260 11.9 The errorPage Attribute 261 11.10 The isErrorPage Attribute 261 11.11 The language Attribute 264 11.12 XML Syntax for Directives 265 Chapter 12 Including Files and Applets in JSP Documents 266 12.1 Including Files at Page Translation Time 268 12.2 Including Files at Request Time 270 Contents xi © Prentice Hall and Sun Microsystems. Personal use only; do not redistribute. 12.3 Including Applets for the Java Plug-In 274 The jsp:plugin Element 275 The jsp:param and jsp:params Elements 277 The jsp:fallback Element 278 Example: Building Shadowed Text 279 Chapter 13 Using JavaBeans with JSP 286 13.1 Basic Bean Use 288 Accessing Bean Properties 290 Setting Bean Properties: Simple Case 290 Installing Bean Classes 291 13.2 Example: StringBean 292 13.3 Setting Bean Properties 294 Associating Individual Properties with Input Parameters 298 Automatic Type Conversions 300 Associating All Properties with Input Parameters 301 13.4 Sharing Beans 302 Conditional Bean Creation 304 Chapter 14 Creating Custom JSP Tag Libraries 308 14.1 The Components That Make Up a Tag Library 310 The Tag Handler Class 310 The Tag Library Descriptor File 311 The JSP File 313 14.2 Defining a Basic Tag 314 The Tag Handler Class 315 The Tag Library Descriptor File 316 The JSP File 318 14.3 Assigning Attributes to Tags 319 The Tag Handler Class 319 The Tag Library Descriptor File 321 The JSP File 322 14.4 Including the Tag Body 323 xii Contents © Prentice Hall and Sun Microsystems. 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The Tag Handler Class 324 The Tag Library Descriptor File 326 The JSP File 328 14.5 Optionally Including the Tag Body 329 The Tag Handler Class 329 The Tag Library Descriptor File 331 The JSP File 332 14.6 Manipulating the Tag Body 334 The Tag Handler Class 334 The Tag Library Descriptor File 335 The JSP File 336 14.7 Including or Manipulating the Tag Body Multiple Times 338 The Tag Handler Class 338 The Tag Library Descriptor File 340 The JSP File 341 14.8 Using Nested Tags 341 The Tag Handler Classes 342 The Tag Library Descriptor File 348 The JSP File 350 Chapter 15 Integrating Servlets and JSP 352 15.1 Forwarding Requests 354 Using Static Resources 354 Supplying Information to the Destination Pages 355 Interpreting Relative URLs in the Destination Page 357 Alternative Means of Getting a RequestDispatcher 358 15.2 Example: An On-Line Travel Agent 358 15.3 Including Static or Dynamic Content 375 15.4 Example: Showing Raw Servlet and JSP Output 377 15.5 Forwarding Requests From JSP Pages 380 Contents xiii © Prentice Hall and Sun Microsystems. 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Part 3 Supporting Technologies 382 Chapter 16 Using HTML Forms 384 16.1 How HTML Forms Transmit Data 385 16.2 The FORM Element 390 16.3 Text Controls 395 Textfields 395 Password Fields 397 Text Areas 398 16.4 Push Buttons 400 Submit Buttons 401 Reset Buttons 404 JavaScript Buttons 405 16.5 Check Boxes and Radio Buttons 405 Check Boxes 406 Radio Buttons 407 16.6 Combo Boxes and List Boxes 409 16.7 File Upload Controls 412 16.8 Server-Side Image Maps 414 IMAGE—Standard Server-Side Image Maps 414 ISMAP—Alternative Server-Side Image Maps 417 16.9 Hidden Fields 419 16.10 Grouping Controls 420 16.11 Controlling Tab Order 422 16.12 A Debugging Web Server 423 EchoServer 423 ThreadedEchoServer 427 NetworkServer 428 Chapter 17 Using Applets As Servlet Front Ends 432 17.1 Sending Data with GET and Displaying the Resultant Page 434 [...]... between their start and end tags Tags that modify their body content Looping tags Nested tags xxv xxvi Introduction • • • • • • Integrating servlets and JSP Forwarding requests from servlets to static and dynamic resources Using servlets to set up beans for use by JSP pages An on-line travel agency combining servlets and JSP Including JSP output in servlets Forwarding requests from JSP pages Part III:... and Sun Microsystems Personal use only; do not redistribute Contents A pp e n d i x Servlet and JSP Quick Reference 518 A.1 Overview of Servlets and JavaServer Pages 519 Advantages of Servlets 519 Advantages of JSP 519 Free Servlet and JSP Software 519 Documentation 520 Servlet Compilation: CLASSPATH Entries 520 Tomcat 3.0 Standard Directories 520 Tomcat 3.1 Standard Directories 520 JSWDK 1.0.1 Standard... Chapter • What servlets are • When and why you would use servlets • What JavaServer Pages are • When and why you would use JSP • Obtaining the servlet and JSP software • Software installation and setup Online version of this first edition of Core Servlets and JavaServer Pages is free for personal use For more information, please see: • • • Second edition of the book: http://www.coreservlets.com Sequel:... http://www.moreservlets.com Servlet and JSP training courses from the author: http://courses.coreservlets.com © Prentice Hall and Sun Microsystems Personal use only; do not redistribute Chapter T his chapter gives a quick overview of servlets and JavaServer Pages (JSP), outlining the major advantages of each It then summarizes how to obtain and configure the software you need to write servlets and develop JSP... book: www.coreservlets.com; Sequel: www.moreservlets.com Servlet and JSP training courses by book’s author: courses.coreservlets.com © Prentice Hall and Sun Microsystems Personal use only; do not redistribute 1.4 The Advantages of JSP extensive API for networking, database access, distributed objects, and the like, whereas PHP requires learning an entirely new language Versus Pure Servlets JSP doesn’t... current price and availability of each item that is for sale In principle, servlets are not restricted to Web or application servers that handle HTTP requests, but can be used for other types of servers as well For Second edition of this book: www.coreservlets.com; Sequel: www.moreservlets.com Servlet and JSP training courses by book’s author: courses.coreservlets.com © Prentice Hall and Sun Microsystems... this book: www.coreservlets.com; Sequel: www.moreservlets.com Servlet and JSP training courses by book’s author: courses.coreservlets.com 7 © Prentice Hall and Sun Microsystems Personal use only; do not redistribute 8 Chapter 1 Overview of Servlets and JavaServer Pages Powerful Servlets support several capabilities that are difficult or impossible to accomplish with regular CGI Servlets can talk directly... and mixed right into the page Second edition of this book: www.coreservlets.com; Sequel: www.moreservlets.com Servlet and JSP training courses by book’s author: courses.coreservlets.com 9 © Prentice Hall and Sun Microsystems Personal use only; do not redistribute 10 Chapter 1 Overview of Servlets and JavaServer Pages Listing 1.1 A sample JSP page ... for servlet and JSP software Links to all URLs mentioned in the text of the book Information on book discounts Reports on servlet and JSP short courses Book additions, updates, and news xxvii xxviii Introduction 1 Servlets 2.1 and 2.2 Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Overview of Servlets and JavaServer Pages, 4 First Servlets, 20 Handling the... setup and configuration details are not standardized So, I include specific details for Apache Tomcat, Sun’s JavaServer Web Development Kit (JSWDK), and the Java Web Server Servlet topics include: • • When and why you would use servlets Obtaining and configuring the servlet and JSP software xxiii xxiv Introduction • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • The basic structure of servlets