Tài liệu Learn Java for Android Development Second Edition pptx

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Learn Java for Android

Development

Second Edition

Jeff Friesen

Apress

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Learn Java for Android Development

Copyright © 2013 by Jeff Friesen

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ISBN 978-1-4302-5722-6

ISBN 978-1-4302-5723-3 (eBook)

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To Amaury.

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v

Contents at a Glance

About the Author .............................................................................................................. xvii

About the Technical Reviewers ......................................................................................... xix

Acknowledgments ............................................................................................................. xxi

Introduction ..................................................................................................................... xxiii

NChapter 1: Getting Started With Java ................................................................................1

NChapter 2: Learning Language Fundamentals .................................................................21

NChapter 3: Discovering Classes and Objects ...................................................................63

NChapter 4: Discovering Inheritance, Polymorphism, and Interfaces .............................105

NChapter 5: Mastering Advanced Language Features Part 1 ..........................................153

NChapter 6: Mastering Advanced Language Features Part 2 ..........................................197

NChapter 7: Exploring the Basic APIs Part 1 ...................................................................247

NChapter 8: Exploring the Basic APIs Part 2 ...................................................................279

NChapter 9: Exploring the Collections Framework ..........................................................327

NChapter 10: Exploring Additional Utility APIs ................................................................407

NChapter 11: Performing Classic I/O ...............................................................................449

NChapter 12: Accessing Networks ..................................................................................525

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vi Contents at a Glance

NChapter 13: Migrating to New I/O ........................................................................... 561

NChapter 14: Accessing Databases .................................................................................603

NAppendix A: Solutions to Exercises ...............................................................................643

NAppendix B: Four of a Kind ............................................................................................713

Index .................................................................................................................................735

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vii

Contents

About the Author .............................................................................................................. xvii

About the Technical Reviewers ......................................................................................... xix

Acknowledgments ............................................................................................................. xxi

Introduction ..................................................................................................................... xxiii

NChapter 1: Getting Started With Java ................................................................................1

What Is Java? ................................................................................................................................2

Java Is a Language ................................................................................................................................................2

Java Is a Platform ..................................................................................................................................................4

Java SE, Java EE, Java ME, and Android ............................................................................................................... 5

Installing and Exploring the JDK ...................................................................................................6

Installing and Exploring the Eclipse IDE ......................................................................................12

Overview of Java APIs .................................................................................................................16

Language-Support and Other Language-Oriented APIs ....................................................................................... 17

Collections-Oriented APIs .................................................................................................................................... 17

Additional Utility APIs ...........................................................................................................................................17

Classic I/O APIs ....................................................................................................................................................17

Networking APIs ..................................................................................................................................................18

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viii Contents

New I/O APIs ........................................................................................................................................................18

Database APIs ......................................................................................................................................................18

Summary .....................................................................................................................................19

NChapter 2: Learning Language Fundamentals .................................................................21

Learning Comments ....................................................................................................................21

Single-Line Comments ........................................................................................................................................22

Multiline Comments .............................................................................................................................................22

Javadoc Comments .............................................................................................................................................23

Learning Identifiers .....................................................................................................................25

Learning Types ............................................................................................................................26

Primitive Types ....................................................................................................................................................26

User-Defined Types ..............................................................................................................................................28

Array Types ..........................................................................................................................................................28

Learning Variables .......................................................................................................................29

Learning Expressions ..................................................................................................................30

Simple Expressions .............................................................................................................................................30

Compound Expressions ....................................................................................................................................... 34

Learning Statements ...................................................................................................................46

Assignment Statements ......................................................................................................................................46

Decision Statements ............................................................................................................................................47

Loop Statements..................................................................................................................................................51

Break and Labeled Break Statements ................................................................................................................. 56

Continue and Labeled Continue Statements........................................................................................................ 58

Summary .....................................................................................................................................60

NChapter 3: Discovering Classes and Objects ...................................................................63

Declaring Classes and Instantiating Objects ...............................................................................63

Declaring Classes ................................................................................................................................................64

Instantiating Objects with the New Operator and a Constructor ......................................................................... 64

Specifying Constructor Parameters and Local Variables ..................................................................................... 65

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Contents ix

Encapsulating State and Behaviors .............................................................................................69

Representing State via Fields .............................................................................................................................. 70

Representing Behaviors via Methods .................................................................................................................. 75

Hiding Information ...............................................................................................................................................84

Initializing Classes and Objects ...................................................................................................89

Class Initializers ...................................................................................................................................................89

Instance Initializers..............................................................................................................................................91

Initialization Order ...............................................................................................................................................93

Collecting Garbage ......................................................................................................................96

Revisiting Arrays .........................................................................................................................99

Summary ...................................................................................................................................104

NChapter 4: Discovering Inheritance, Polymorphism, and Interfaces .............................105

Building Class Hierarchies.........................................................................................................105

Extending Classes .............................................................................................................................................106

The Ultimate Superclass ....................................................................................................................................112

Composition .......................................................................................................................................................122

The Trouble with Implementation Inheritance ................................................................................................... 122

Changing Form ..........................................................................................................................126

Upcasting and Late Binding ............................................................................................................................... 127

Abstract Classes and Abstract Methods ............................................................................................................ 131

Downcasting and Runtime Type Identification................................................................................................... 133

Covariant Return Types ......................................................................................................................................136

Formalizing Class Interfaces .....................................................................................................139

Declaring Interfaces ..........................................................................................................................................139

Implementing Interfaces ....................................................................................................................................140

Extending Interfaces ..........................................................................................................................................144

Why Use Interfaces? ..........................................................................................................................................146

Summary ...................................................................................................................................152

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x Contents

NChapter 5: Mastering Advanced Language Features Part 1 ..........................................153

Mastering Nested Types ............................................................................................................153

Static Member Classes ......................................................................................................................................153

Nonstatic Member Classes ................................................................................................................................157

Anonymous Classes ...........................................................................................................................................161

Local Classes .....................................................................................................................................................164

Interfaces within Classes ..................................................................................................................................166

Mastering Packages ..................................................................................................................167

What Are Packages? ..........................................................................................................................................168

The Package Statement.....................................................................................................................................169

The Import Statement ........................................................................................................................................169

Searching for Packages and Types .................................................................................................................... 170

Playing with Packages .......................................................................................................................................172

Packages and JAR Files ....................................................................................................................................176

Mastering Static Imports ...........................................................................................................177

Mastering Exceptions ................................................................................................................179

What Are Exceptions? ........................................................................................................................................179

Representing Exceptions in Source Code .......................................................................................................... 179

Throwing Exceptions .........................................................................................................................................184

Handling Exceptions ..........................................................................................................................................187

Performing Cleanup ...........................................................................................................................................190

Summary ...................................................................................................................................195

NChapter 6: Mastering Advanced Language Features Part 2 ..........................................197

Mastering Assertions .................................................................................................................197

Declaring Assertions ..........................................................................................................................................198

Using Assertions ................................................................................................................................................199

Avoiding Assertions ...........................................................................................................................................205

Enabling and Disabling Assertions .................................................................................................................... 206

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Contents xi

Mastering Annotations ..............................................................................................................207

Discovering Annotations .................................................................................................................................... 207

Declaring Annotation Types and Annotating Source Code ................................................................................. 210

Processing Annotations .....................................................................................................................................215

Mastering Generics ...................................................................................................................217

Collections and the Need for Type Safety .......................................................................................................... 217

Generic Types ....................................................................................................................................................220

Generic Methods ................................................................................................................................................ 229

Arrays and Generics ..........................................................................................................................................232

Mastering Enums ......................................................................................................................234

The Trouble with Traditional Enumerated Types ................................................................................................ 234

The Enum Alternative ........................................................................................................................................235

The Enum Class .................................................................................................................................................241

Summary ...................................................................................................................................245

NChapter 7: Exploring the Basic APIs Part 1 ...................................................................247

Exploring the Math APIs ............................................................................................................247

Math and StrictMath ..........................................................................................................................................247

BigDecimal ........................................................................................................................................................255

BigInteger ..........................................................................................................................................................260

Exploring String Management ...................................................................................................264

String .................................................................................................................................................................264

StringBuffer and StringBuilder .......................................................................................................................... 268

Obtaining Package Information .................................................................................................270

Summary ...................................................................................................................................276

NChapter 8: Exploring the Basic APIs Part 2 ...................................................................279

Exploring the Primitive Type Wrapper Classes ..........................................................................279

Boolean ..............................................................................................................................................................280

Character ...........................................................................................................................................................281

Float and Double ................................................................................................................................................282

Integer, Long, Short, and Byte ............................................................................................................................ 286

Number ..............................................................................................................................................................288

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xii Contents

Exploring Threads ......................................................................................................................288

Runnable and Thread .........................................................................................................................................289

Thread Synchronization ..................................................................................................................................... 298

Exploring System Capabilities ...................................................................................................314

System ............................................................................................................................................................... 314

Runtime and Process .........................................................................................................................................319

Summary ...................................................................................................................................324

NChapter 9: Exploring the Collections Framework ..........................................................327

Exploring Collections Framework Fundamentals ......................................................................327

Comparable Versus Comparator ........................................................................................................................ 328

Iterable and Collection .......................................................................................................................................330

Exploring Lists ...........................................................................................................................337

ArrayList ............................................................................................................................................................341

LinkedList ..........................................................................................................................................................342

Exploring Sets ...........................................................................................................................344

TreeSet...............................................................................................................................................................344

HashSet ............................................................................................................................................................. 346

EnumSet ............................................................................................................................................................350

Exploring Sorted Sets ................................................................................................................353

Exploring Navigable Sets ...........................................................................................................361

Exploring Queues ......................................................................................................................364

PriorityQueue .....................................................................................................................................................365

Exploring Deques ......................................................................................................................368

ArrayDeque ........................................................................................................................................................372

Exploring Maps ..........................................................................................................................373

TreeMap .............................................................................................................................................................377

HashMap ............................................................................................................................................................378

IdentityHashMap ................................................................................................................................................384

EnumMap...........................................................................................................................................................386

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Exploring Sorted Maps ........................................................................................................387

Exploring Navigable Maps ...................................................................................................390

Exploring the Arrays and Collections Utility APIs .................................................................394

Exploring the Legacy Collection APIs ..................................................................................398

Summary .............................................................................................................................404

NChapter 10: Exploring Additional Utility APIs ..........................................................407

Exploring the Concurrency Utilities .....................................................................................407

Executors ....................................................................................................................................................407

Synchronizers .............................................................................................................................................417

Concurrent Collections ...............................................................................................................................420

Locks ..........................................................................................................................................................422

Atomic Variables .........................................................................................................................................425

Exploring the Date Class .....................................................................................................426

Exploring the Formatter Class .............................................................................................428

Exploring the Random Class................................................................................................430

Exploring the Scanner Class................................................................................................432

Exploring the ZIP and JAR APIs ...........................................................................................434

Exploring the ZIP API ...................................................................................................................................435

Exploring the JAR API .................................................................................................................................442

Summary .............................................................................................................................447

NChapter 11: Performing Classic I/O .........................................................................449

Working with the File API ....................................................................................................449

Working with the RandomAccessFile API ............................................................................462

Working with Streams .........................................................................................................473

Stream Classes Overview ...........................................................................................................................474

OutputStream and InputStream ..................................................................................................................475

ByteArrayOutputStream and ByteArrayInputStream ...................................................................................478

FileOutputStream and FileInputStream ......................................................................................................479

PipedOutputStream and PipedInputStream ................................................................................................482

FilterOutputStream and FilterInputStream .................................................................................................485

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BufferedOutputStream and BufferedInputStream ............................................................................................. 493

DataOutputStream and DataInputStream .......................................................................................................... 494

Object Serialization and Deserialization ............................................................................................................ 496

PrintStream........................................................................................................................................................510

Working with Writers and Readers ............................................................................................511

Writer and Reader Classes Overview ................................................................................................................ 512

Writer and Reader..............................................................................................................................................514

OutputStreamWriter and InputStreamReader .................................................................................................... 514

FileWriter and FileReader ..................................................................................................................................516

Summary ...................................................................................................................................524

NChapter 12: Accessing Networks ..................................................................................525

Accessing Networks via Sockets ..............................................................................................526

Socket Addresses ..............................................................................................................................................528

Socket Options...................................................................................................................................................529

Socket and ServerSocket ..................................................................................................................................530

DatagramSocket and MulticastSocket .............................................................................................................. 536

Accessing Networks via URLs ...................................................................................................543

URL and URLConnection ....................................................................................................................................543

URLEncoder and URLDecoder ............................................................................................................................547

Accessing Network Interfaces and Interface Addresses ...........................................................549

Managing Cookies .....................................................................................................................555

Summary ...................................................................................................................................559

NChapter 13: Migrating to New I/O ..................................................................................561

Working with Buffers .................................................................................................................562

Buffer and Its Children .......................................................................................................................................562

Buffers in Depth .................................................................................................................................................566

Working with Channels .............................................................................................................575

Channel and Its Children ....................................................................................................................................576

Channels in Depth .............................................................................................................................................580

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Working With Regular Expressions ......................................................................................589

Pattern, PatternSyntaxException, and Matcher ..........................................................................................589

Character Classes .......................................................................................................................................593

Capturing Groups ........................................................................................................................................594

Boundary Matchers and Zero-Length Matches ..........................................................................................595

Quantifiers ..................................................................................................................................................596

Practical Regular Expressions ....................................................................................................................598

Summary .............................................................................................................................601

NChapter 14: Accessing Databases ...........................................................................603

Introducing Java DB ............................................................................................................604

Java DB Installation and Configuration .......................................................................................................605

Java DB Demos ...........................................................................................................................................607

Java DB Command-Line Tools ....................................................................................................................609

Introducing SQLite ...............................................................................................................611

Accessing Databases via JDBC ...........................................................................................613

Data Sources, Drivers, and Connections .....................................................................................................613

Exceptions ..................................................................................................................................................616

Statements .................................................................................................................................................620

Metadata ....................................................................................................................................................633

Summary .............................................................................................................................639

NAppendix A: Solutions to Exercises .........................................................................643

Chapter 1: Getting Started with Java ..................................................................................643

Chapter 2: Learning Language Fundamentals .....................................................................644

Chapter 3: Discovering Classes and Objects .......................................................................647

Chapter 4: Discovering Inheritance, Polymorphism, and Interfaces ....................................651

Chapter 5: Mastering Advanced Language Features Part 1 ................................................659

Chapter 6: Mastering Advanced Language Features Part 2 ................................................666

Chapter 7: Exploring the Basic APIs Part 1 ..........................................................................671

Chapter 8: Exploring the Basic APIs Part 2 ..........................................................................676

Chapter 9: Exploring the Collections Framework ................................................................679

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