Table of Contents

Part 1  Background   1

1  Dynamic web sites   3

1.1 The boring life of a web browser 4

1.2 The simple ideas behind dynamic web content 6

1.3 What you need to run JSTL 9

JSP containers 10

1.4 Real-world web applications 11

1.5 Summary 14

2  Foundation: XML and JSP   15

2.1 Introduction to XML 16

A dose of tag terminology 17

The relevant rules of XML 21

2.2 Introduction to JSP 23

JSP tag syntax 24

Standard JSP tags 25

JSP tag libraries 29

Other JSP directives 32

JSP comments 33

How JSP organizes data 34

2.3 Summary 39

Part 2  Learning JSTL   41

3  The expression language   43

3.1 Expressions and the <c:out> tag 44

What expressions look like 45

Where expressions work 46

Default values in <c:out> 46

Special characters and <c:out> 47

3.2 Scoped variables and the expression language 48

Basic syntax to access scoped variables 48

Different types of scoped data 50

3.3 Request parameters and the expression language 55

HTML forms 55

A page that reads request parameters 62

3.4 More powerful expressions 63

Different ways to access properties 64

Accessing other data with the expression language 65

Comparisons 67

Boolean operations and parentheses 69

Multiple expressions 70

3.5 Saving data with <c:set> 71

3.6 Deleting data with <c:remove> 74

3.7 Summary 75

4  Controlling flow with conditions   77

4.1 Different kinds of decisions 79

4.2 Yes-or-no conditions with <c:if> 79

The basic syntax of <c:if> 80

Using <c:if> within HTML tags 82

Multiple <c:if> tags 82

Nested <c:if> tags 84

The var and scope attributes 86

4.3 Mutually exclusive conditions with <c:choose>, <c:when>, and <c:otherwise> 88

Why JSTL has complex conditional tags 88

How the complex con-ditional tags work 89

Rules for using the complex conditional tags 93

4.4 Summary 94

5  Controlling flow with loops   95

5.1 General-purpose looping with <c:forEach> 96

5.2 Iterating over strings with <c:forTokens> 98

How JSTL parses strings 100

5.3 Advanced iteration with <c:forEach> and <c:forTokens> 101

Looping over part of a collection 101

Looping over numbers 104

Loop status 106

5.4 Loop example: scrolling through results 107

Understanding the example 109

Using varStatus in the example 111

5.5 Summary 113

6  Importing text   115

6.1 Including text with the <c:import> tag 117

Absolute and relative URLs 117

Retrieving data from URLs 121

Saving information for later 122

Communicating with imported pages 124

Import example: a customized header 127

6.2 Redirecting with <c:redirect> 132

6.3 Formatting URLs with <c:url> 134

How to use <c:url> 134

Why to use <c:url> 135

6.4 Summary 137

7  Selecting XML fragments   139

7.1 XPath?s vision of an XML document 140

7.2 XPath?s basic syntax 142

Deep descendants 143

Attributes 144

Predicates and element order 145

Strings and booleans 146

7.3 XPath variables and JSTL 147

7.4 JSTL, XPath, and namespaces 148

7.5 More advanced XPath 149

Nodes and axes 149

Contexts 150

Further reading 151

7.6 Summary 152

8  Working with XML fragments   153

8.1 Parsing documents with <x:parse> 154

Sources of XML 155

8.2 Accessing XML with <x:out> and <x:set> 156

Finding a document 156

The <x:out> tag 157

The <x:set> tag 158

8.3 Control flow based on XML documents 159

Simple conditions with <x:if> 160

Compound conditions with <x:choose> 162

Looping over parts of a document with <x:forEach> 164

8.4 XML transformations using JSTL 169

Simple transformations with <x:transform> 170

Using the var attribute 172

XSLT parameters 174

Advantages of using XSLT within JSTL 174

8.5 An XML example: reading RSS files 175

8.6 Summary 179

9  Database-driven pages   181

9.1 When to use JSTL?s database support 183

When to use databases 183

Direct access from JSP pages 183

9.2 Setting up a database connection with <sql:setDataSource> 185

Caution against <sql:setDataSource> 188

9.3 Performing queries with <sql:query> 189

Performing a database query 190

Reading a query?s results 191

Limiting the size of a query?s result 197

9.4 Modifying data with <sql:update> 199

Simple uses of the <sql:update> tag 199

Measuring the effect of an <sql:update> tag 200

9.5 Using <sql:param> with adjustable queries 201

Template queries 202

Safe, convenient parameters with <sql:param> 202

Date parameters with <sql:dateParam> 205

9.6 Managing transactions with <sql:transaction> 206

The <sql:transaction> tag 207

Transaction isolation 210

9.7 SQL example: a hit counter 211

9.8 Summary 213

10  Formatting and internationalization   215

10.1 Printing numbers with <fmt:formatNumber> 216

Basic usage of <fmt:formatNumber> 217

Different ways to specify a value 218

Storing a number instead of printing it 219

Printing different types of numbers: percentages and currencies 219

Grouping digits together ? or not 222

Controlling how many digits print 223

More control: custom number patterns 226

10.2 Printing dates with <fmt:formatDate> 227

Differences from <fmt:formatNumber> 227

Printing times, dates, or both 228

Printing longer or shorter dates and times 229

More control: custom date patterns 230

10.3 Reading numbers with <fmt:parseNumber> 232

Why you might want to parse numbers 233

How <fmt:parseNumber> works by default 233

Changing <fmt:parseNumber>?s parsing rules 235

10.4 Reading dates with <fmt:parseDate> 236

How <fmt:parseDate> parses dates by default 236

Changing how <fmt:parseDate> parses dates 237

10.5 Overriding time zones with <fmt:timeZone> and <fmt:setTimeZone> 238

How JSTL figures out time zones by default 239

Setting time zones for individual tags 239

Long-lasting changes with <fmt:setTimeZone> 240

Temporary changes with <fmt:timeZone> 241

10.6 Overriding locales with <fmt:setLocale> 242

How to identify locales 243

The parseLocale attribute for <fmt:parseNumber> and <fmt:parseDate> 244

10.7 Internationalizing text messages with <fmt:message>, <fmt:param>, <fmt:bundle>, and <fmt:setBundle> 245

Using <fmt:message> 245

Loading a bundle family with <fmt:bundle> and <fmt:setBundle> 247

10.8 Summary 248

Part 3  JSTL in action   249

11  Common tasks   251

11.1 Handling checkbox parameters 252

The HTML form 253

A simple checkbox handler 254

Handling some check boxes specially 256

11.2 Accepting dates 257

The HTML form 258

Handling the form and reading the date 259

11.3 Handling errors 261

Ignoring the issue 262

Catching errors with <c:catch> 263

Passing errors to an error page 266

11.4 Validating input 268

Different kinds of form validation 268

Tasks involved when validating a form 269

A sample form validation 271

11.5 Summary 277

12  Dynamic features for web sites   279

12.1 An online survey 280

What our survey looks like 281

Setting up the survey database 281

Adding survey questions to pages 284

How the survey works 285

12.2 A message board 291

What our message board looks like 291

Setting up the message database 293

Linking to appropriate message boards 294

How the message board works 295

12.3 Summary 300

13  Case study in building a web site   301

13.1 Managing the layout 303

A framework for channels 303

Modular channels 305

13.2 Adding dynamic content 309

Including RSS channels 309

Including other dynamic content 311

13.3 Registering users 313

Modifying the header 313

The registration form 314

Saving the registration 318

The user database 319

13.4 Authenticating users 320

Logging in users 320

Some notes about authentication 321

13.5 Personalizing the site 322

Filling in a form automatically 322

Displaying a chosen RSS feed 324

13.6 Summary 325

Part 4  JSTL for programmers   327

14  Control and performance   329

14.1 Scripting elements and the JSTL rtexprvalue libraries 330

Warning against scripting expressions 331

JSTL?s dual libraries 332

Scripting variables and <jsp:useBean> 333

14.2 Modifying properties with <c:set> 334

14.3 Advanced techniques for importing text 335

Representing imported text as a java.io.Reader 335

Character encoding 337

14.4 Advanced XML parsing and manipulation 338

XML data formats 338

Telling <x:parse> where a document came from 340

Efficient parsing with org.xml.sax.XMLFilter 341

Efficient transformations with javax.xml.transform.Result 343

14.5 Deciphering requests with <fmt:requestEncoding> 343

14.6 Exposing data to JSP pages 344

Saving data to a scope 344

Exposing dynamic data structures 346

Writing JavaBeans 347

14.7 Configuring JSTL 349

Providing default information to JSTL tags 349

Managing database access 352

Managing internationalization 354

14.8 Enforcing good page-authoring habits 355

Requiring script-free pages 356

Enumerating legal tag libraries 357

14.9 Summary 359

15  Using JSTL to develop custom tags   361

15.1 Developing and installing tag libraries 362

JSTL?s support for tag-handler developers 363

The tag-library descriptor (TLD) 363

Installing and using a tag library 366

15.2 Developing conditional tags 366

A simple conditional tag 367

A conditional tag with attributes 370

Integrating custom conditional tags with standard tags 376

Using the expression language 377

15.3 Developing iteration tags 378

A simple loop tag 379

More advanced iteration tags 386

15.4 Summary 387

A  JSTL reference   389

A.1 Expression language syntax 390

A.2 Core tag library 392

A.3 XML tag library 397

A.4 Database tag library 401

A.5 Formatting tag library 404

B  JSTL API (for developers)   409

B.1 Configuration variables 410

B.2 Conditions and loops 413

B.3 Interoperating with JSTL?s database tags 415

B.4 Using JSTL?s localization algorithms 417

C  Database tags and SQL   421

C.1 SQL and <sql:update> 422

C.2 SQL and <sql:query> 427

C.3 SQL miscellany 429

C.4 Summary 430

D  References and resources   433

D.1 JSP Standard Tag Library 434

D.2 XML-related references 435

D.3 Databases 435

D.4 Related standards 436

D.5 Miscellaneous references 437

index 439