Jakarta Struts for Dummies

as A Web Developer, You’ve Probably Heard A Lot About Jakarta Struts, The Popular Open Source Framework For Creating Web Applications In Java. Struts Is The De Facto Standard For Java-based Web Applications; In Fact, Some People Consider It The Yardstick By Which All Other Web Application Frameworks Are Measured. the Struts Framework Is Based On A Classic Model-view-controller (mvc) Design Paradigm That Combines Java Servlets, Java Server Pages (jsp), Custom Tags, And Message Resources Into A Unified Framework. jakarta Struts For Dummies Will Get You Up And Running With Struts In A Hurry, So You Can control The Business Logic Of Your Applications design The View For Javaserver Pages validate Data use Tiles To Dynamically Create Pages secure And Troubleshoot Your Applications, And More jakarta Struts Saves You Coding Time And Helps You Create An Extensible Development Environment. jakarta Struts For Dummies Provides The Information You Need When You Need It, And Even Lets You Get Your Feet Wet Right Away By Creating A Special “jump Start” Application In Part I. jakarta Struts For Dummies Helps You understand And Apply The Model-view-controller (mvc) Design Pattern integrate Struts Into A Web Application Environment use Tag Libraries To Simplify Your Jsp Pages maintain Control With Effective Security Features internationalize Web Applications With A Feature That Creates Easy-to-update Text Content, So International Viewers Can See Pages In Their Own Languages represent All Types Of Data, From One Or Two Items To A Huge And Complex Database extend Jakarta’s Functionality With Plug-ins use Logging To Help You Troubleshoot An Application loaded With Tips, Examples, And Explanatory Sidebars, This Plain-english Guide To Jakarta Struts Will Have You Creating Web Applications With Struts Before You Can Say “java”. Table of Contents 7 Introduction 15 About This Book 15 How to Use This Book 16 Foolish Assumptions 16 Conventions Used in This Book 17 How This Book Is Organized 17 Part I: Getting to Know Jakarta Struts 18 Part II: Starting from the Core 18 Part III: Expanding Your Development Options 18 Part IV: Putting It All Together 18 Part V: The Part of Tens 18 Part VI: Appendixes 19 Icons Used in This Book 19 Where to Go from Here 19 Part I Getting to Know Jakarta Struts 21 Chapter 1 Starting with the Basics 23 What Is Jakarta Struts? 23 Structuring a Web Application 24 Using Java Servlets 26 Creating JavaServer Pages 27 Using JavaBeans 28 Understanding the Model-View-Controller Design Pattern 31 How Struts enforces the MVC pattern 33 The MVC design pattern 32 What is a design pattern? 32 Chapter 2 Laying the Groundwork 39 Getting Java 40 Downloading and installing Java 40 Setting the Java Home 42 Getting the Web Container 43 Downloading Tomcat to Windows 43 Installing Tomcat under Windows 44 Installing Tomcat under Linux or Mac OS X 45 Starting and testing Tomcat 46 Choosing Your Development Environment 47 Downloading and Installing Eclipse 48 Getting the Tomcat Launcher Plug-in for Eclipse 49 Configuring the Tomcat Launcher plug-in 50 Downloading and installing the Tomcat Launcher plug-in 49 Getting Struts 53 Reviewing the components of Struts 55 Downloading Struts 54 Testing Your Web Application Development Environment 57 Chapter 3: Creating a Simple Web Application with Struts 61 Designing Your First Struts Application 62 Application requirements 62 Determining which components to use 63 Putting Everything in Place 63 Creating the project in Eclipse 64 Setting up the application folders 66 Importing the Struts files 68 Creating the JavaServer Pages 73 The login.jsp page 73 The loggedin.jsp page 78 Using message resources 81 Making the Formbean 83 Adding a JavaBean 88 Creating an Action 90 Configuring Struts 92 Defining web.xml 92 Configuring Struts with struts-config.xml 95 Strutting Your Stuff: Running the Application 99 Deploying the Login application 99 Testing the application 99 Debugging with Eclipse 101 Part II: Starting from the Core 103 Chapter 4: Controlling with the Controller 105 Understanding the Struts Controller Classes 105 Working with the Master Controller - the ActionServlet 107 Starting the Servlet 108 Processing requests 111 Shutting down the Servlet 111 Working with the Controller’s Helper - RequestProcessor 112 Getting Down to Work: Extending ActionClass 114 Using the execute method 115 Predefined Action classes 117 Action Forms 122 Chapter 5: Creating the Model 123 Understanding the Model 123 Working with Business Objects 125 Meeting requirements for business objects 125 Adding helper classes 126 Using JavaBeans 126 Implementing the Model 126 Achieving persistence 127 Getting MySQL 127 Downloading and installing MySQL 128 Downloading MySQL Connector/J 129 Setting Up Your IDE and Web Container 129 Importing the class library into Eclipse 130 Adding the class library to Tomcat 130 Working with MySQL 131 Starting and stopping MySQL 132 Creating a database 134 Creating a table in MySQL 135 Inserting data in the users table 135 Executing queries 136 Exiting the MySQL command tool 137 Connecting the Model to the Database 137 Working with JDBC 138 Retrieving multiple records 140 Pooling Connections 144 Jakarta Commons DBCP 145 Using connection pooling 146 Configuring the data source in Struts 148 Chapter 6: Designing the View 151 Choosing JSP or an Alternative 151 Template engines 151 XML tools 153 Internationalization 153 Creating multinational applications 154 Using one source for String type constants 162 Mediating between the View and the Controller 163 Configuring the formbean 164 Interactions with the formbean 165 Preparing the form with the reset method 166 Indexing data 166 Validating data 166 Declarative form validation 168 Notifying Users of Problems 168 Mediating Automatically 170 Configuring the DynaActionForm class 170 Differences between ActionForm and DynaActionForm 171 Chapter 7: Setting the Configuration 173 Stringing the Parts Together 173 Editing the Web Container Configuration File 174 The ServletContext configuration tag 176 Listener configuration 177 ActionServlet configuration 177 ActionServlet mapping 180 Adding in the tag libraries 180 A complete example of a web.xml file 181 Modifying the Struts Configuration File 183 DataSource configuration 183 Formbean configuration 185 Global exceptions 188 Global forwards 189 Action mapping 190 Controller configuration 193 Message resource configuration 195 Plug-in configuration 197 Complete example of a struts-config.xml file 198 Part III: Expanding Your Development Options 203 Chapter 8: Exceptions to the Rule 205 Java Errors and Exceptions 206 Try/catch block 207 Throwing exceptions 207 Wrapping it up in finally 208 Exception Strategies 210 Catching exceptions 210 Exception information 210 Writing Your Own Exception Classes 211 Using Chained Exceptions 212 Asserting Yourself 213 Handling Exceptions Yourself 215 Saving information 216 Recovering from errors 216 Inform the user 216 Fail gracefully 216 Declarative Exception Handling 217 Declaring the exception 218 Global or local exception handling 218 Extending ExceptionHandler 219 Handling RuntimeExceptions in Struts 221 Chapter 9: Getting Friendly with Plug-ins 223 Using the PlugIn Interface 223 Implementing and Configuring Your Own Plug-in 224 Working with the Validator Plug-in 226 Configuring the Validator plug-in 227 Using the Validator plug-in 227 Extending the ValidatorForm class 228 Configuring the Validator plug-in in the config file 229 Defining the fields to validate 229 Tweaking other files 235 Try out the modified Login application 236 Looking more closely at validation.xml 237 Using the Validator with DynaActionForms 239 Chapter 10: Getting a Helping Hand with Tag Libraries 239 Using Tag Libraries 240 Expressing with the Expression Language 241 Identifiers 242 Literals 242 Operators 243 Implicit Objects 244 Using the Struts-EL Tag Library 244 Getting the Struts-EL tag library 245 Beans-EL library 246 HTML-EL library 246 Logic-EL library 247 Working with the JSP Standard Tag Library 248 Core library 248 Formatting library 252 SQL library 255 XML library 258 Other Struts Tag Libraries 259 Tiles library 259 Struts-Layout library 259 Display library 260 Looking at Java Server Faces 260 Chapter 11: Working with Page Composition Techniques 263 Making Your Page Layout Life Easier 263 Simplifying with Includes 266 Using the Tiles Framework 270 Configuring Tiles 274 Tiles definitions 274 Using XML for Tile definitions 276 Chapter 12: Securing Your Application 279 Making the Application Responsible 279 Logging in and authenticating a user 280 Authorizing a user 280 Authentication and authorization in Struts 280 Customizing the RequestProcessor Class 282 Declaring Security in Your Web Container 284 Step 1 — Setting up the roles 284 Step 2 — Defining the realms 284 Step 3 — Specifying authorization areas 287 Step 4 — Defining authentication methods 289 Examples of declaring authorization and authentication 290 Part IV: Putting It All Together 293 Chapter 13: Logging Your Actions 295 Logging for Everyone 295 Using Commons Logging 296 Using Java 1.4 Logging 298 Working with the Log4J Package 298 Chapter 14: Creating the MusicCollection.com Application 301 Description of the Application 301 Creating the Database Schema 303 Configuring DataSource 304 Creating the Pages and Associated Files 304 Logging On from the Home Page 306 Home page design 306 LoginForm 307 LoginValidation and validation.xml 307 LoginAction 308 LoginBean, model layer, and exception handling 309 Action mapping configuration 310 Continued User Authentication 311 Creating a User Account 312 Join page 313 The Join form 313 Join validation 314 JoinAction 315 JoinBean 316 Configuring the action mapping for JoinAction 318 The Welcome page 318 Displaying the User’s Albums 319 The MusicList page 319 The MusicList form 320 MusicListAction 321 MusicListBean 322 Configuring action mapping for MusicListAction 323 Creating, Editing, or Deleting an Album 324 The Album page 324 AlbumForm 324 StartupManager 326 AlbumValidation 326 AlbumAction 327 AlbumBean 332 Logging Off 336 LogoffAction 336 Configuring action mapping for LogoffAction 337 Handling Exceptions 337 Our own exception 337 The custom ExceptionHandler 337 Declarative exception handling 338 Error pages 338 Running the Application 339 Part V: The Part of Tens 341 Chapter 15: Ten Helpful Extensions to Struts 343 ImageButtonBeanManager 344 Struts Spring Plug-in 344 Hibernate 345 Expresso 345 SSLExt 346 Struts Action Scripting 346 StrutsDoc 347 StrutsTestCase for JUnit 348 Struts Workflow Extension 349 Easy Struts Plug-in 349 Chapter 16: Ten Ways to Find More Information 351 Struts Web Site 352 Struts Mailing Lists 352 Articles 353 Tutorials 353 Consultants 354 Classes 355 Struts Resources Web Sites 355 Sample Applications 356 Struts Documentation 357 Friends and Colleagues 358 Part VI: Appendixes 359 Appendix A: Struts-EL and JSTL Tag Library Syntax 361 Beans-EL Library Syntax 361 HTML-EL Library Syntax 362 Logic-EL Library Syntax 375 JSTL Core Library Syntax 377 JSTL Formatting Library Syntax 380 JSTL SQL Library Syntax 384 JSTL XML Library Syntax 386 Appendix B: Glossary 389 Index 393 As a Web developer, you've probably heard a lot about Jakarta Struts, the popular open source framework for creating Web applications in Java. Struts is the de facto standard for Java-based Web applications; in fact, some people consider it the yardstick by which all other Web application frameworks are measured. The Struts framework is based on a classic Model-View-Controller (MVC) design paradigm that combines Java servlets, Java Server Pages (JSP), custom tags, and message resources into a unified framework. Jakarta Struts For Dummies will get you up and running with Struts in a hurry, so you can Control the business logic of your applications Design the view for JavaServer Pages Validate data Use tiles to dynamically create pages Secure and troubleshoot your applications, and more Jakarta Struts saves you coding time and helps you create an extensible development environment. Jakarta Struts For Dummies provides the information you need when you need it, and even lets you get your feet wet right away by creating a special "jump start" application in Part I. Jakarta Struts For Dummies helps you Understand and apply the Model-View-Controller (MVC) design pattern Integrate Struts into a Web application environment Use tag libraries to simplify your JSP pages Maintain control with effective security features Internationalize Web applications with a feature that creates easy-to-update text content, so international viewers can see pages in their own languages Represent all types of data, from one or two items to a huge and complex database Extend Jakarta's functionality with plug-ins Use logging to help you troubleshoot an application Loaded with tips, examples, and explanatory sidebars, this plain-English guide to Jakarta Struts will have you creating Web applications with Struts before you can say "Java". * Shows Java Web developers how to develop Java-based Web applications using the popular open source Jakarta Struts framework* Sun Microsystems estimates that there are three million Java developers* According to the Apache Software Foundation, Struts is rapidly growing in popularity among the Java community and is used by a number of high-profile companies, including Ford, McDonald's, Citigroup, Bank of America, and Federal Express* Provides a quick "jump-start" application to get novices up and running in a hurry* Examines the Model-View-Controller design paradigm, exception handling, plug-i