overriding and overloading

pxr08 2003-08-19 01:52:55

高手能具体说说overriding 和overloading之间有什么区别和联系妈？

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cuihao 2003-08-19

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overriding参数列表和返回值必须相同，方法体不同

overloading只和参数列表有关，

AlanLuo_2002 2003-08-19

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通俗的说overloading使得一个函数可以接受不同的参数，比方说Sysetm.out.println()这个println()方法，他既可以打印String,int,float也可以答应其他类型的变量，所以说这个就是overloading。overriding就是把父类的函数覆盖掉，比方：
class A
{
public void method1(){System.out.println("Class A");}

}
class B extends A
{
public void method1(){System.out.println("Class B");}
}
如果你A b=new B();调用b.method1();那么将调用的是B中的method1()

whyxx 2003-08-19

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看看think in java吧,里面有很详细的说明

Method Overloading and OverRiding

Discover object oriented programming with Java in this unique tutorial. This book uses Java and Eclipse to write and generate output for examples in topics such as classes, interfaces, overloading, and overriding. Interactive Object Oriented Programming in Java uniquely presents its material in a dialogue with the reader to encourage thinking and experimentation. Later chapters cover further Java programming concepts, such as abstract classes, packages, and exception handling. At each stage you’ll be challenged by the author to help you absorb the information and become a proficient Java programmer. Additionally, each chapter contains simple assignments to encourage you and boost your confidence level. What You Will Learn Become proficient in object oriented programming Test your skills in the basics of Java Develop as a Java programmer Use the Eclipse IDE to write your code Who This Book Is For Software developers and software testers. Table of Contents Chapter 1: Test your skill in language fundamentals Chapter 2: Class Chapter 3: Inheritance Chapter 4: Overloading Chapter 5: Overriding Chapter 6: Abstract Class Chapter 7: Interface Chapter 8: Package Chapter 9: OOPs Concepts Revisited Chapter 10: Use of static keyword Chapter 11: Exceptions Chapter 12: An introduction to design patterns Appendix A: Solution to the Assignments Appendix B: Frequently asked questions Appendix C: Some Useful Resources

Java: The Complete Reference, Eleventh Edition By 作者: Herbert Schildt ISBN-10 书号: 1260440230 ISBN-13 书号: 9781260440232 Edition 版本: 11 出版日期: 2018-12-12 pages 页数: (1955) The Definitive Java Programming Guide Fully updated for Java SE 11, Java: The Complete Reference, Eleventh Edition explains how to develop, compile, debug, and run Java programs. Best-selling programming author Herb Schildt covers the entire Java language, including its syntax, keywords, and fundamental programming principles. You’ll also find information on key portions of the Java API library, such as I/O, the Collections Framework, the stream library, and the concurrency utilities. Swing, JavaBeans, and servlets are examined and numerous examples demonstrate Java in action. Of course, the very important module system is discussed in detail. This Oracle Press resource also offers an introduction to JShell, Java’s interactive programming tool. Best of all, the book is written in the clear, crisp, uncompromising style that has made Schildt the choice of millions worldwide. Coverage includes: Data types, variables, arrays, and operators Control statements Classes, objects, and methods Method overloading and overriding Inheritance Local variable type inference Interfaces and packages Exception handling Multithreaded programming Enumerations, autoboxing, and annotations The I/O classes Generics Lambda expressions Modules String handling The Collections Framework Networking Event handling AWT Swing The Concurrent API The Stream API Regular expressions JavaBeans Servlets Much, much more

Chapter 1: Introduction to C++ Concepts and Features 7 Introduction 7 Creating a C++ project 8 Program structure, execution flow, and runtime objects 10 The structural programming approach 14 Understanding the object-oriented programming approach 17 Explaining inheritance, overloading, and overriding 19 Understanding polymorphism 24 Event handlers and Message Passing Interface 28 Linked list, queue, and stack examples 34 Chapter 2: The Concepts of Process and Thread 45 Introduction 45 Processes and threads 46 Explaining the process model 47 Implementation of processes 51 IPC – Interprocess Communication 55 Solving classical IPC problems 65 Implementation of the thread model 75 Thread usage 81 Implementing threads in user space 89 Implementing threads in the kernel 99 Chapter 3: Managing Threads 105 Introduction 105 Processes versus threads 106 Permissive versus preemptive multitasking 110 Explaining the Windows Thread object 111 Basic thread management 112 Implementing threads without synchronization 121 Using synchronized threads 127 Win32 synchronization objects and techniques 133 Chapter 4: Message Passing 141 Introduction 141 Explaining the Message Passing Interface 142 Understanding a message queue 147 Using the thread message queue 156 Communicating through the pipe object 161 Chapter 5: Thread Synchronization and Concurrent Operations 167 Introduction 167 Pseudoparallelism 168 Understanding process and thread priority 168 The Windows dispatcher object and scheduling 176 Using mutex 177 Using semaphore 187 Using event 197 Using critical section 206 Using pipes 215 Chapter 6: Threads in the .NET Framework 233 Introduction 233 Managed versus unmanaged code 234 How threading works in .NET 235 The difference between foreground and background threads 243 Understanding the .NET synchronization essentials 247 Locking and avoiding deadlocks 254 Thread safety and types of the .NET framework 261 Signaling with event wait handles 263 Event-based Asynchronous Pattern 269 Using the BackgroundWorker class 276 Interrupting, aborting, and safe canceling the thread execution 281 Non-blocking synchronization 291 Signaling with Wait and Pulse 294 The Barrier class 299 Chapter 7: Understanding Concurrent Code Design 309 Introduction 309 How to design parallel applications 310 Understanding parallelism in code design 316 Turning on to a parallel approach 324 Improving the performance factors 332 Chapter 8: Advanced Thread Management 341 Introduction 341 Using thread pools 342 Customizing the thread pool dispatcher 354 Using remote threading 371 Appendix 381 Installing MySQL Connector/C 381 Installing WinDDK – Driver Development Kit 384 Setting up a Visual Studio project for driver compilation 386 Using the DebugView application 392 Setting up a Visual Studio project for OpenMP compilation 393 Index 397

《快学Scala》英文第二版： Scala for the Impatient Second Edition Cay S. Horstmann 目录： 1 THE BASICS A1 1 1.1 The Scala Interpreter 1 1.2 Declaring Values and Variables 4 1.3 Commonly Used Types 5 1.4 Arithmetic and Operator Overloading 6 1.5 More about Calling Methods 8 1.6 The apply Method 9 1.7 Scaladoc 10 Exercises 15 2 CONTROL STRUCTURES AND FUNCTIONS A1 17 2.1 Conditional Expressions 18 2.2 Statement Termination 19 2.3 Block Expressions and Assignments 20 vii Contents2.4 Input and Output 21 2.5 Loops 22 2.6 Advanced for Loops 24 2.7 Functions 25 2.8 Default and Named Arguments L1 26 2.9 Variable Arguments L1 26 2.10 Procedures 28 2.11 Lazy Values L1 28 2.12 Exceptions 29 Exercises 31 3 WORKING WITH ARRAYS A1 35 3.1 Fixed-Length Arrays 35 3.2 Variable-Length Arrays: Array Buffers 36 3.3 Traversing Arrays and Array Buffers 37 3.4 Transforming Arrays 38 3.5 Common Algorithms 40 3.6 Deciphering Scaladoc 41 3.7 Multidimensional Arrays 42 3.8 Interoperating with Java 43 Exercises 44 4 MAPS AND TUPLES A1 47 4.1 Constructing a Map 48 4.2 Accessing Map Values 48 4.3 Updating Map Values 49 4.4 Iterating over Maps 50 4.5 Sorted Maps 50 4.6 Interoperating with Java 50 4.7 Tuples 51 4.8 Zipping 52 Exercises 52 viii Contents5 CLASSES A1 55 5.1 Simple Classes and Parameterless Methods 55 5.2 Properties with Getters and Setters 56 5.3 Properties with Only Getters 59 5.4 Object-Private Fields 60 5.5 Bean Properties L1 61 5.6 Auxiliary Constructors 62 5.7 The Primary Constructor 63 5.8 Nested Classes L1 66 Exercises 68 6 OBJECTS A1 71 6.1 Singletons 71 6.2 Companion Objects 72 6.3 Objects Extending a Class or Trait 73 6.4 The apply Method 73 6.5 Application Objects 74 6.6 Enumerations 75 Exercises 77 7 PACKAGES AND IMPORTS A1 79 7.1 Packages 80 7.2 Scope Rules 81 7.3 Chained Package Clauses 83 7.4 Top-of-File Notation 83 7.5 Package Objects 83 7.6 Package Visibility 84 7.7 Imports 85 7.8 Imports Can Be Anywhere 85 7.9 Renaming and Hiding Members 86 7.10 Implicit Imports 86 Exercises 87 ix Contents8 INHERITANCE A1 91 8.1 Extending a Class 91 8.2 Overriding Methods 92 8.3 Type Checks and Casts 93 8.4 Protected Fields and Methods 94 8.5 Superclass Construction 94 8.6 Overriding Fields 95 8.7 Anonymous Subclasses 97 8.8 Abstract Classes 97 8.9 Abstract Fields 97 8.10 Construction Order and Early Definitions L3 98 8.11 The Scala Inheritance Hierarchy 100 8.12 Object Equality L1 102 8.13 Value Classes L2 103 Exercises 105 9 FILES AND REGULAR EXPRESSIONS A1 109 9.1 Reading Lines 109 9.2 Reading Characters 110 9.3 Reading Tokens and Numbers 111 9.4 Reading from URLs and Other Sources 111 9.5 Reading Binary Files 112 9.6 Writing Text Files 112 9.7 Visiting Directories 112 9.8 Serialization 113 9.9 Process Control A2 114 9.10 Regular Expressions 116 9.11 Regular Expression Groups 117 Exercises 118 10 TRAITS L1 121 10.1 Why No Multiple Inheritance? 121 10.2 Traits as Interfaces 123 10.3 Traits with Concrete Implementations 124 x Contents10.4 Objects with Traits 125 10.5 Layered Traits 125 10.6 Overriding Abstract Methods in Traits 127 10.7 Traits for Rich Interfaces 127 10.8 Concrete Fields in Traits 128 10.9 Abstract Fields in Traits 130 10.10 Trait Construction Order 130 10.11 Initializing Trait Fields 132 10.12 Traits Extending Classes 133 10.13 Self Types L2 134 10.14 What Happens under the Hood 135 Exercises 137 11 OPERATORS L1 141 11.1 Identifiers 142 11.2 Infix Operators 143 11.3 Unary Operators 143 11.4 Assignment Operators 144 11.5 Precedence 144 11.6 Associativity 145 11.7 The apply and update Methods 146 11.8 Extractors L2 147 11.9 Extractors with One or No Arguments L2 149 11.10 The unapplySeq Method L2 149 11.11 Dynamic Invocation L2 150 Exercises 153 12 HIGHER-ORDER FUNCTIONS L1 157 12.1 Functions as Values 157 12.2 Anonymous Functions 159 12.3 Functions with Function Parameters 160 12.4 Parameter Inference 160 12.5 Useful Higher-Order Functions 161 12.6 Closures 162 xi Contents12.7 SAM Conversions 163 12.8 Currying 164 12.9 Control Abstractions 166 12.10 The return Expression 167 Exercises 168 13 COLLECTIONS A2 171 13.1 The Main Collections Traits 172 13.2 Mutable and Immutable Collections 173 13.3 Sequences 174 13.4 Lists 175 13.5 Sets 177 13.6 Operators for Adding or Removing Elements 178 13.7 Common Methods 180 13.8 Mapping a Function 182 13.9 Reducing, Folding, and Scanning A3 184 13.10 Zipping 187 13.11 Iterators 188 13.12 Streams A3 189 13.13 Lazy Views A3 190 13.14 Interoperability with Java Collections 191 13.15 Parallel Collections 193 Exercises 194 14 PATTERN MATCHING AND CASE CLASSES A2 197 14.1 A Better Switch 198 14.2 Guards 199 14.3 Variables in Patterns 199 14.4 Type Patterns 200 14.5 Matching Arrays, Lists, and Tuples 201 14.6 Extractors 202 14.7 Patterns in Variable Declarations 203 14.8 Patterns in for Expressions 204 14.9 Case Classes 205 xii Contents14.10 The copy Method and Named Parameters 205 14.11 Infix Notation in case Clauses 206 14.12 Matching Nested Structures 207 14.13 Are Case Classes Evil? 208 14.14 Sealed Classes 209 14.15 Simulating Enumerations 209 14.16 The Option Type 210 14.17 Partial Functions L2 211 Exercises 212 15 ANNOTATIONS A2 215 15.1 What Are Annotations? 216 15.2 What Can Be Annotated? 216 15.3 Annotation Arguments 217 15.4 Annotation Implementations 218 15.5 Annotations for Java Features 219 15.5.1 Java Modifiers 219 15.5.2 Marker Interfaces 220 15.5.3 Checked Exceptions 220 15.5.4 Variable Arguments 221 15.5.5 JavaBeans 221 15.6 Annotations for Optimizations 222 15.6.1 Tail Recursion 222 15.6.2 Jump Table Generation and Inlining 223 15.6.3 Eliding Methods 224 15.6.4 Specialization for Primitive Types 225 15.7 Annotations for Errors and Warnings 226 Exercises 227 16 XML PROCESSING A2 229 16.1 XML Literals 230 16.2 XML Nodes 230 16.3 Element Attributes 232 16.4 Embedded Expressions 233 xiii Contents16.5 Expressions in Attributes 234 16.6 Uncommon Node Types 235 16.7 XPath-like Expressions 235 16.8 Pattern Matching 237 16.9 Modifying Elements and Attributes 238 16.10 Transforming XML 239 16.11 Loading and Saving 239 16.12 Namespaces 242 Exercises 243 17 FUTURES A2 247 17.1 Running Tasks in the Future 248 17.2 Waiting for Results 250 17.3 The Try Class 251 17.4 Callbacks 251 17.5 Composing Future Tasks 252 17.6 Other Future Transformations 255 17.7 Methods in the Future Object 256 17.8 Promises 258 17.9 Execution Contexts 260 Exercises 260 18 TYPE PARAMETERS L2 265 18.1 Generic Classes 266 18.2 Generic Functions 266 18.3 Bounds for Type Variables 266 18.4 View Bounds 268 18.5 Context Bounds 268 18.6 The ClassTag Context Bound 269 18.7 Multiple Bounds 269 18.8 Type Constraints L3 269 18.9 Variance 271 18.10 Co- and Contravariant Positions 272 xiv Contents18.11 Objects Can’t Be Generic 274 18.12 Wildcards 275 Exercises 275 19 ADVANCED TYPES L2 279 19.1 Singleton Types 280 19.2 Type Projections 281 19.3 Paths 282 19.4 Type Aliases 283 19.5 Structural Types 283 19.6 Compound Types 284 19.7 Infix Types 285 19.8 Existential Types 286 19.9 The Scala Type System 287 19.10 Self Types 288 19.11 Dependency Injection 289 19.12 Abstract Types L3 291 19.13 Family Polymorphism L3 293 19.14 Higher-Kinded Types L3 296 Exercises 299 20 PARSING A3 303 20.1 Grammars 304 20.2 Combining Parser Operations 305 20.3 Transforming Parser Results 307 20.4 Discarding Tokens 308 20.5 Generating Parse Trees 309 20.6 Avoiding Left Recursion 310 20.7 More Combinators 311 20.8 Avoiding Backtracking 314 20.9 Packrat Parsers 314 20.10 What Exactly Are Parsers? 315 20.11 Regex Parsers 316 Contents xv20.12 Token-Based Parsers 317 20.13 Error Handling 319 Exercises 320 21 IMPLICITS L3 323 21.1 Implicit Conversions 324 21.2 Using Implicits for Enriching Existing Classes 324 21.3 Importing Implicits 325 21.4 Rules for Implicit Conversions 326 21.5 Implicit Parameters 328 21.6 Implicit Conversions with Implicit Parameters 329 21.7 Context Bounds 329 21.8 Type Classes 331 21.9 Evidence 333 21.10 The @implicitNotFound Annotation 334 21.11 CanBuildFrom Demystified 334 Exercises 336 Index 338

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