Table of Contents
2010年最新PHP类的精缩归纳
Home php教程 php手册 chengren-成人-php系列

chengren-成人-php系列

Jun 14, 2016 am 12:02 AM
php re code Open source programming programming language software development

2010年最新PHP类的精缩归纳

 

一:结构和调用(实例化):

class className{} ,调用:$obj = new className();当类有构造函数时,还应传入参数。如$obj = new className($v,$v2...);

二:构造函数和析构函数:

1、构造函数用于初始化:使用__construct(),可带参数。

2、但析构函数不能带参数(用于在销去一个类之前执行一些操作或功能)。析构函数用__destruct()做名称。在脚本执行结束时,PHP会销掉内存中的对象,因此可不用析造函数,但有些比如COOKIE等,就应当要用此函数销掉。

知识点:在PHP4中也提供了构造函数,但使用的是与类同名的类方法,在PHP5仍能兼容这种做法,当一个类中没有包含__construct时,会查找与类同名的方法,如果找到,就认为是构造函数,如下:

class test
{ var $b;
function test() { $this->b=5; }
function addab($c) { return $this->b+$c; }
}
$a = new test(); echo $a->addab(4); // 返回 9

3、PHP不会自动调用父类的构造函数(不支持构造函数重载),必须使用parent关键字显式地调用。

class employee{
function __construct()....
}
class Manager extents Employee{
function __construct(){
parent::_construct();
echo '这个子类的父类构造函数调用了!';
}
}

当然也可以调用与该实例没有任何关系的其它类的构造函数。只需在__construct()前加上类名即可。如:

otherClassName::__construct();

类的主家庭成员:属性、方法、常量、静态成员

三、类的属性:

有两种方法对类的属性赋值或取值。

1、使用公共作用域public关键词。

2、使用__set()和__get()来分别赋值和取值,前者称为设置方法(setter)或修改方法(mutator),后者称为访问方法(accessor)或获取方法(getter)。建议使用这种方法:优点:

A、可在__set()统一进行数据验证。

B、便于统一管理属性。

注意:

第一:__set()和__get()只对私有属性起作用,对于用public定义的属性,它们两个都懒理搭理,如下:

class test{
protected $a=9,$b=2,$c;
public $d;
function __set($n,$v) { $this->$n = $v+2; }
function __get($name) { return $this->$name+2; }
}
$a = new test();
$a->b =5;
echo "
";
echo $a->b;

实例只对$a,$b,$c的设置会经过__set和__get过滤与返回,对于$d,就不会起作用。如$a->d=5,再返回还是5。

第二:__set($n,$v)要带两个参数。而__get($n)只能有一个参数。实例:

class test{
private $a=5,$b=6,$c;
function __set($n,$v)
{
if($n=='a'&&$n>0)
$this->$n = $v;
else
$this->$n = $v+2;
}
function __get($name)
{
return $this->$name; //如果改为return $this->$name + $this->addab(); 如调用a的值,实际返回的是a+a+b的值。默认为5+5+6=16。
}
function addab()
{ return $this->a + $this->b; }
}
$e=new test();
$e->a = 11; //注意写法:类的内部用$this->$n即变量的写法,但外部实例要用$e->a的方式。
$e->b = 12; //get 14
$e->k = 22;

类的属性可自由扩展,如上例的k,不管是否用__set,当一个实例建立起来后,可以用$e->newProperty = xx;直接来创造一个属性,但不建议这么做。

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
2 weeks ago By 尊渡假赌尊渡假赌尊渡假赌
Repo: How To Revive Teammates
4 weeks ago By 尊渡假赌尊渡假赌尊渡假赌
Hello Kitty Island Adventure: How To Get Giant Seeds
3 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

PHP 8.4 Installation and Upgrade guide for Ubuntu and Debian PHP 8.4 Installation and Upgrade guide for Ubuntu and Debian Dec 24, 2024 pm 04:42 PM

PHP 8.4 brings several new features, security improvements, and performance improvements with healthy amounts of feature deprecations and removals. This guide explains how to install PHP 8.4 or upgrade to PHP 8.4 on Ubuntu, Debian, or their derivati

How To Set Up Visual Studio Code (VS Code) for PHP Development How To Set Up Visual Studio Code (VS Code) for PHP Development Dec 20, 2024 am 11:31 AM

Visual Studio Code, also known as VS Code, is a free source code editor — or integrated development environment (IDE) — available for all major operating systems. With a large collection of extensions for many programming languages, VS Code can be c

How do you parse and process HTML/XML in PHP? How do you parse and process HTML/XML in PHP? Feb 07, 2025 am 11:57 AM

This tutorial demonstrates how to efficiently process XML documents using PHP. XML (eXtensible Markup Language) is a versatile text-based markup language designed for both human readability and machine parsing. It's commonly used for data storage an

PHP Program to Count Vowels in a String PHP Program to Count Vowels in a String Feb 07, 2025 pm 12:12 PM

A string is a sequence of characters, including letters, numbers, and symbols. This tutorial will learn how to calculate the number of vowels in a given string in PHP using different methods. The vowels in English are a, e, i, o, u, and they can be uppercase or lowercase. What is a vowel? Vowels are alphabetic characters that represent a specific pronunciation. There are five vowels in English, including uppercase and lowercase: a, e, i, o, u Example 1 Input: String = "Tutorialspoint" Output: 6 explain The vowels in the string "Tutorialspoint" are u, o, i, a, o, i. There are 6 yuan in total

The Key to Coding: Unlocking the Power of Python for Beginners The Key to Coding: Unlocking the Power of Python for Beginners Oct 11, 2024 pm 12:17 PM

Python is an ideal programming introduction language for beginners through its ease of learning and powerful features. Its basics include: Variables: used to store data (numbers, strings, lists, etc.). Data type: Defines the type of data in the variable (integer, floating point, etc.). Operators: used for mathematical operations and comparisons. Control flow: Control the flow of code execution (conditional statements, loops).

Java Made Simple: A Beginner's Guide to Programming Power Java Made Simple: A Beginner's Guide to Programming Power Oct 11, 2024 pm 06:30 PM

Java Made Simple: A Beginner's Guide to Programming Power Introduction Java is a powerful programming language used in everything from mobile applications to enterprise-level systems. For beginners, Java's syntax is simple and easy to understand, making it an ideal choice for learning programming. Basic Syntax Java uses a class-based object-oriented programming paradigm. Classes are templates that organize related data and behavior together. Here is a simple Java class example: publicclassPerson{privateStringname;privateintage;

Create the Future: Java Programming for Absolute Beginners Create the Future: Java Programming for Absolute Beginners Oct 13, 2024 pm 01:32 PM

Java is a popular programming language that can be learned by both beginners and experienced developers. This tutorial starts with basic concepts and progresses through advanced topics. After installing the Java Development Kit, you can practice programming by creating a simple "Hello, World!" program. After you understand the code, use the command prompt to compile and run the program, and "Hello, World!" will be output on the console. Learning Java starts your programming journey, and as your mastery deepens, you can create more complex applications.

Problem-Solving with Python: Unlock Powerful Solutions as a Beginner Coder Problem-Solving with Python: Unlock Powerful Solutions as a Beginner Coder Oct 11, 2024 pm 08:58 PM

Pythonempowersbeginnersinproblem-solving.Itsuser-friendlysyntax,extensivelibrary,andfeaturessuchasvariables,conditionalstatements,andloopsenableefficientcodedevelopment.Frommanagingdatatocontrollingprogramflowandperformingrepetitivetasks,Pythonprovid

See all articles