Tài liệu Java 7 New Features Cookbook ppt

Java 7 New Features

Cookbook

Over 100 comprehensive recipes to get you up-to-speed

with all the exciting new features of Java 7

Richard M. Reese

Jennifer L. Reese

BIRMINGHAM - MUMBAI

Java 7 New Features Cookbook

Copyright © 2012 Packt Publishing

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First published: February 2012

Production Reference: 1160212

Published by Packt Publishing Ltd.

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ISBN 978-1-84968-562-7

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Cover Image by J.Blaminsky ([email protected])

Credits

Authors

Richard M. Reese

Jennifer L. Reese

Reviewers

Jacek Laskowski

Deepak Vohra

Acquisition Editor

Amey Kanse

Lead Technical Editor

Hyacintha D'Souza

Technical Editors

Ankita Shashi

Lubna Shaikh

Copy Editor

Leonard D'Silva

Project Coordinator

Michelle Quadros

Proofreader

Mario Cecere

Indexer

Rekha Nair

Graphics

Manu Joseph

Valentina D'silva

Production Coordinators

Arvindkumar Gupta

Melwyn D'sa

Cover Work

Arvindkumar Gupta

About the Authors

Richard M. Reese is an associate professor teaching Computer Science at Tarleton

State University in Stephenville, Texas. Previously, he worked in the industry for over 16

years in the aerospace and telephone industries. He earned his Ph.D. in Computer Science

from Texas A&M University and served four years in the Air Force, primarily in the field of

communication intelligence.

Outside of the classroom, he enjoys tending to his vegetable garden, maintaining his

aquariums, and running with his dog, Zoey. He also enjoys relaxing with an episode

of Firefly and is ever hopeful for the return of the series.

He has written numerous publications and has also written the EJB 3.1 Cookbook.

Jennifer L. Reese holds a B.S. degree from Tarleton State University. She currently works

as a software engineer for Local Government Solutions in Waxahachie, Texas, developing

software for the county government. Prior to graduation, she worked for the Center for

Agribusiness Excellence at Tarleton, where she used Java in conjunction with GIS software

to analyze crop and weather data.

In her free time, she enjoys reading, cooking, and traveling, especially to any destination

with a beach. She is also a musician and appreciates a variety of musical genres.

Acknowledgement

No book can be written without the help of others. To this end we are thankful for the support

of Karla, our wife and mother, whose patience and reviews have made this effort possible. In

addition, we would like to thank the editorial staff of Packt and our reviewers for their input

which has resulted in a much better book than it might otherwise have been.

About the Reviewers

Jacek Laskowski has over 15 years of IT experience, focusing on software development

and architecture design with open source and commercial product offerings. He's interested

in Service-Oriented Architecture (SOA) with Java Enterprise Edition (Java EE), Business Process

Management (BPMS), and Business Rule Management System (BRMS) solutions. He is a

seasoned technology professional with a strong software development and advisory track

record. His interests revolve around Java Enterprise Edition and supportive solutions like

Enterprise OSGi, Service Component Architecture (SCA), WS-BPEL, and WS-BPMN to name

a few.

He is a founder and leader of Warszawa Java User Group, and has been a speaker at local and

international conferences. He has been organizing Confitura (formerly Javarsovia), Warsjawa,

and Eclipse DemoCamp conferences for the Java community in Poland. He contributes to

open source projects—Apache OpenEJB and Apache Geronimo. He envisages himself using

functional languages in projects and the decision to learn Clojure (a little bit of JRuby, Scala,

F#, and Dart lately) influences his current self-learning activities. It's been quite recently that

he's got into Android, too.

Knowledge sharing is his passion. He mentors students, and is an author of IBM Redbooks

publications and has also contributed to a few other books as a technical reviewer. While

supporting business partners and customers with their use of IBM WebSphere BPM products,

he regularly runs courses and workshops. He is a member of the NetBeans Dream Team—

highly-skilled and motivated NetBeans users.

He actively blogs at http://blog.japila.pl and http://blog.jaceklaskowski.pl.

Follow @jaceklaskowski on twitter.

I'd like to thank my family—my wife, Agata, and my three kids, Iweta, Patryk,

and Maksym, for their constant support, encouragement, and patience.

Without you, I wouldn't have achieved so much. Love you all immensely.

Deepak Vohra is a consultant and a principal member of the NuBean.com software

company. Deepak is a Sun Certified Java Programmer and Web Component Developer and

has worked in the fields of XML and Java programming and J2EE for over five years. Deepak

is the co-author of the Apress book Pro XML Development with Java Technology and was

the technical reviewer for the O'Reilly book WebLogic: The Definitive Guide. Deepak was

also the technical reviewer for the Course Technology PTR book Ruby Programming for the

Absolute Beginner, and the technical editor for the Manning Publications book Prototype and

Scriptaculous in Action. Deepak is also the author of the Packt Publishing books JDBC 4.0 and

Oracle JDeveloper for J2EE Development, Processing XML documents with Oracle JDeveloper

11g, and EJB 3.0 Database Persistence with Oracle Fusion Middleware 11g.

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Table of Contents

Preface 1

Chapter 1: Java Language Improvements 7

Introduction 7

Using string literals in switch statements 9

Using underscores in literals to improve code readability 13

Using the try-with-resources block to improve exception handling code 16

Creating a resource that can be used with the try-with-resources technique 20

Catching multiple exception types to improve type checking 24

Rethrowing exceptions in Java 7 29

Using the diamond operator for constructor type inference 31

Using the @SafeVarargs annotation 35

Chapter 2: Locating Files and Directories Using Paths 41

Introduction 41

Creating a Path object 44

Interoperability between java.io.File and java.nio.file.Files 49

Converting a relative path into an absolute path 50

Removing redundancies by normalizing a path 53

Combining paths using path resolution 56

Creating a path between two locations 61

Converting between path types 65

Determining whether two paths are equivalent 67

Managing symbolic links 70

Chapter 3: Obtaining File and Directory Information 75

Introduction 75

Determining the file content type 78

Obtaining a single attribute at a time using the getAttribute method 79

Obtaining a map of file attributes 82

ii

Table of Contents

Getting file and directory information 84

Determining operating system support for attribute views 89

Maintaining basic file attributes using the BasicFileAttributeView 93

Maintaining POSIX file attributes using the PosixFileAttributeView 96

Maintaining FAT table attributes using the DosFileAttributeView 98

Maintaining file ownership attributes using the FileOwnerAttributeView 100

Maintaining a file's ACL using the AclFileAttributeView 101

Maintaining user-defined file attributes using the

UserDefinedFileAttributeView 106

Chapter 4: Managing Files and Directories 109

Introduction 109

Creating files and directories 110

Controlling how a file is copied 113

Managing temporary files and directories 118

Setting time-related attributes of a file or directory 120

Managing file ownership 124

Managing ACL file permissions 126

Managing POSIX attributes 132

Moving a file and a directory 139

Deleting files or directories 143

Managing symbolic links 145

Chapter 5: Managing Filesystems 149

Introduction 149

Getting FileStore information 150

Getting Filesystem information 153

Using the SimpleFileVisitor class to traverse filesystems 155

Deleting a directory using the SimpleFileVisitor class 160

Copying a directory using the SimpleFileVisitor class 162

Processing the contents of a directory by using the

DirectoryStream interface 165

Filtering a directory using globbing 168

Writing your own directory filter 171

Monitoring file events using WatchEvents 173

Understanding the ZIP filesystem provider 178

Chapter 6: Stream IO in Java 7 181

Introduction 181

Managing simple files 184

Using buffered IO for files 187

Random access IO using the SeekableByteChannel 190

iii

Table of Contents

Managing asynchronous communication using the

AsynchronousServerSocketChannel class 196

Writing to a file using the 202

AsynchronousFileChannel class 202

Reading from a file using the 206

AsynchronousFileChannel class 206

Using the SecureDirectoryStream class 210

Chapter 7: Graphical User Interface Improvements 213

Introduction 213

Mixing heavyweight and lightweight components 217

Managing window types 219

Managing the opacity of a window 222

Creating a varying gradient translucent window 224

Managing the shape of a window 227

Using the new border types in Java 7 231

Handling multiple file selection in the FileDialog class 235

Controlling the print dialog box type 238

Using the new JLayer decorator for a password field 240

Chapter 8: Handling Events 247

Introduction 247

Managing extra mouse buttons and high resolution mouse wheels 248

Controlling a focus when displaying a window 252

Using secondary loops to mimic modal dialog boxes 255

Handling spurious thread wakeups 260

Handling applet initialization status with event handlers 262

Chapter 9: Database, Security, and System Enhancements 267

Introduction 267

Using the RowSetFactory class 270

Java 7 database enhancements 273

Using the ExtendedSSLSession interface 278

Using the platform MXBeans for JVM or system process load monitoring 283

Redirecting input and output from operating system's processes 287

Embedding a JNLP file in an HTML page 291

Chapter 10: Concurrent Processing 297

Introduction 297

Using join/fork framework in Java 299

Using the reusable synchronization barrier Phaser 303

Using the new ConcurrentLinkedDeque safely with multiple threads 312

Using the new LinkedTransferQueue class 319

Supporting multiple threads using the ThreadLocalRandom class 325

iv

Table of Contents

Chapter 11: Odds and Ends 329

Introduction 329

Handling weeks in Java 7 332

Using the Currency class in Java 7 335

Using the NumericShaper.Range enumeration to support the display

of digits 336

JavaBean enhancements in Java 7 339

Handling locales and the Locale.Builder class in Java 7 342

Handling null references 346

Using the new BitSet methods in Java 7 352

Index 355

Preface

With the release of Java 7, numerous new features have been added that significantly improve

the developer's ability to create and maintain Java applications. These include language

improvements, such as better exception handling techniques, and additions to the Java core

libraries, such as new threading mechanisms.

This cookbook covers these new features using a series of recipes. Each recipe addresses

one or more new features and provides a template for using these features. This should make

it easier to understand the features along with when and how they can be used. Step-by-step

instructions are provided to guide the reader through the recipes and are followed by an

explanation of the resulting code.

The book starts with a discussion of the new language enhancements, which is followed by a

series of chapters, each addressing a specific area such as file and directory management.

The reader is assumed to be familiar with the features of Java 6. The book does not need to

be read in sequential order, which enables the reader to choose the chapters and recipes that

are of interest. However, it is recommended that the reader cover the first chapter, as many of

the features found there will be used in subsequent recipes. If other new Java 7 features are

used in a recipe, then cross references are provided to the related recipes.

What this book covers

Chapter 1, Java Language Improvements: In this chapter, we examine the various

language improvements introduced as part of Project Coin. These features include simple

improvements such as using underscores in literals and the use of strings with switch

statements. Also, more significant improvements such as the try-with-resources block and

the introduction of the diamond operator are detailed.

Chapter 2, Locating Files and Directories Using Paths: The Path class is introduced in this

chapter. It is used in this and other chapters and is the basis for much of the new file-related

additions to Java 7.

Preface

2

Chapter 3, Obtaining File and Directory Information: Many applications need access to

specific file and directory information. How to access this file information is addressed here,

including accessing such information as the basic file attributes, Posix attributes, and a file's

access control list.

Chapter 4, Managing Files and Directories: In this chapter, the basic mechanisms for

managing files and directories are covered, including such actions as creating and deleting

files. Also addressed are the use of temporary files and the management of symbolic links.

Chapter 5, Managing File Systems: Here a number of interesting topics, such as how to obtain

the filesystem and file store information, the classes used to traverse a file structure, how to

watch for file and directory events, and how to work with a ZIP file system are presented.

Chapter 6, Stream IO in Java 7: NIO2 is introduced. New techniques for performing

asynchronous IO are detailed along with new approaches for performing random access

IO and using a secure directory stream.

Chapter 7, Graphical User Interface Improvements: There have been several additions to

Java 7 to address the creation of a GUI interface. It is now possible to create windows with

different shapes and windows that are transparent. In addition, numerous enhancements

are explained such as the use of the JLayer decorator, which improves the ability to overlay

graphics on a window.

Chapter 8, Handling Events: In this chapter, new methods for working with various application

events are examined. Java 7 now supports extra mouse buttons and precision mouse wheels.

The ability to control a window's focus has been improved and secondary loops have been

introduced to mimic the behavior of modal dialog boxes.

Chapter 9, Database, Security, and System Enhancements: Various database improvements

such as the introduction of the new RowSetFactory class are illustrated along with how to take

advantage of new SSL support. In addition, other system improvements such as additional

support for MXBeans are demonstrated.

Chapter 10, Concurrent Processing: Several new classes have been added to support the

use of threads, including classes that support the fork/join paradigm, the phaser model, an

improved dequeue class, and a transfer queue class. The new ThreadLocalRandom class,

used to generate random numbers, is explained.

Chapter 11, Odds and Ends: This chapter demonstrates many other Java 7 improvements

such as new support for week, years, and currency. Also included in this chapter is the

improved support for dealing with null references.

What you need for this book

The software required for this book includes the Java Development Kit (JDK) 1.7 or later. Any

integrated development environment that supports Java 7 can be used to create and execute

the recipes. The examples in this book were developed using NetBeans 7.0.1.