Java for WebObjects Developers-P1

Nếu bạn có kế hoạch xây dựng các ứng dụng WebObjects, bạn cần phải trở thành một lập trình Java. Java là một ngôn ngữ lập trình phổ biến có sẵn trong nhiều ngữ cảnh khác nhau để thực hiện các giải pháp phần mềm thật. Nhưng Java là nhiều hơn chỉ là một ngôn ngữ lập trình, nó là một bộ công cụ, một thời gian chạy với một máy ảo, một cảnh quan rộng các gói đầy đủ các lớp học thể tái sử dụng. Java là một môi trường. Học Java "môi trường? có vẻ như áp...
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Java for WebObjects Developers-P1 Java for WebObjects Developers-P1Provides a quick-start guide for developerslearning to use Java with WebObjects Apple Computer, Inc.2003 All rights reserved under the copyright laws of the United Statesand other countries.1 Infinite Loop, Cupertino, CA 95014 USAJava for WebObjects DevelopersVersion 5.0Apple, the Apple logo, and WebObects are trademarks of AppleComputer, Inc., registered inthe United States and other countries. Use in commerce other thanas “fair use” is prohibitedby law except by express license from Apple Computer, Inc.Enterprise Objects Framework is aregistered trademark of NeXT Computer, Inc. Java and all Java-based trademarks and logos aretrademarks or registered trademarks of Sun Microsystems, Inc. in theU.S. and other countries.All other trademarks mentioned belong to their respective owners.We at Apple have tried to make the information contained in guide asaccurate and reliable aspossible. Nevertheless, Apple disclaims any warranty of any kind,whether express or implied, asto any matter whatsoever relating to this manual, including withoutlimitation the merchantabilityor fitness for any particular purpose. Apple will from time to timerevise the software describedin this manual and the manual itself, and reserves the right to makesuch changes withoutobligation to notify the purchaser. In no event shall Apple be liable forany indirect, special,incidental, or consequential damages arising out of purchase or useof this manual or theinformation contained herein.Produced by Apple Technical Publications. Original authored by KaiChristiansen. Updated forWebObjects 5 by Malcolm Crawford. Publication management byKatherine Wenc.1 IntroductionMandatory Reading—Start HereJava for WebObjects developers—Java in 21 minutesIf you plan on building WebObjects applications, you need to becomea Java programmer. Java is apopular programming language available in many diverse contexts forimplementing real softwaresolutions. But Java is more than just a programming language—it is aset of tools, a runtime with avirtual machine, a broad landscape of packages full of reusableclasses. Java is an environment.Learning Java “the environment” seems overwhelming the first timeyou approach it. There are reamsof on-line materials, and bookstores are brimming with all kinds ofJava books. It may be difficult todecide where to start, especially if your primary goal is to learn how todevelop applications withWebObjects.Aside from the glamour of applets with sophisticated graphical userinterfaces, and the rigorsof multi-threaded or networked programming, Java turns out to be arather simple language forhumble, general-purpose jobs running on a plain old computer. Withsome basic ideas, and somefamiliarity with the most commonly used language constructs, youcan go a long way. This isespecially true when your Java code is part of a larger system thathandles a lot of the details already.To get started, all you need is the Java relevant for a WebObjectsdeveloper.But Java “the language” is still something to learn. It is a general-purpose programming language,and it is object-oriented. The term “object-oriented” is vague andspooky to some, fresh and intuitiveto others, even old hat to a few. Mostly, it means just good, modernsoftware technology. Objectorientedprogramming is based on a small set of powerful concepts andsomewhat specializedterminology. From this perspective, it should be clear that Java is away of thinking.Your job, however, is to communicate your thinking to others—acomputer, or another programmer.From this perspective, Java is a way of speaking.The basic goal—getting you to think and speak JavaWhile it may take a bit longer than 21 minutes to digest this guide, itwill likely take a lot less of yourtime and energy than other approaches, while achieving similarresults. The content is based on thefact that, to begin developing WebObjects applications you don’tneed to know everything in the Javaenvironment, nor even everything about the Java language itself. Thisguide presents the Java youabsolutely must know before you start.6 Java for WebObjects Developers • Chapter 1The approach is designed to be simple and direct. Java and the worldof object-orientedprogramming is in some ways so simple and direct that it isparadoxically confusing. The obviousmeaning is somehow elusive. This is not to say that there isn’t greatsophistication and complexityin object-oriented design and implementation. But the basic way ofthinking and the general style ofcoding—in Java—is clear and straightforward.This guide follows a straightforward narrative. To see the forest forthe trees—and to be convincedthat the forest is a nice place to live—you need to hear a simple,useful, Java story. Without ex ...