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Table of Contents
通過(guò)例子學(xué)習(xí)
再來(lái)個(gè)例子
Laravel中使用
Home Backend Development PHP Tutorial [Object-Oriented Bootcamp] 7-Statics-and-Constants

[Object-Oriented Bootcamp] 7-Statics-and-Constants

Jun 23, 2016 am 09:15 AM

你可能會(huì)在網(wǎng)絡(luò)上看到一些文章,它提到靜態(tài)是有害的。他們是什么意思呢?這是真的么?好,這節(jié)讓我們來(lái)談?wù)勥@個(gè)。

通過(guò)例子學(xué)習(xí)

改造前,動(dòng)態(tài)調(diào)用如下:

<?php class Math{  public function add(){    return array_sum(func_get_args());  }} $math = new Math; var_dump($math->add(1, 2, 3)); //結(jié)果int(6) 

從原始動(dòng)態(tài)改造后,靜態(tài)調(diào)用如下:

<?php class Math{  public static function add(...$nums){ //靜態(tài)方法    return array_sum($nums);  }} var_dump(Math::add(1, 2, 3, 4)); //結(jié)果int(10) 

改造為靜態(tài)方法后,直接用類名調(diào)用即可。

再來(lái)個(gè)例子

靜態(tài)變量的使用:

<?php class Person {   public static $age = 1;   public function haveBirthday(){    static::$age += 1;  }} $joe = new Person();$joe->haveBirthday();$joe->haveBirthday(); $jane = new Person();$jane->haveBirthday(); echoPerson::$age; //非2,結(jié)果為4。$age變量為靜態(tài),共享。 

const 標(biāo)識(shí)符:

<?php class BankAccount {  // const標(biāo)識(shí)不改變的值,用大寫字符表示 ;類似 private static  const TAX = 0.09; } echoBankAccount::TAX; 

Laravel中使用

Illuminate\Support 中 Str 類大量使用了 static 靜態(tài)變量和靜態(tài)方法,例如:

echoStr::lower("FOOBAR"); //結(jié)果:foobarechoStr::camel(); 

參考鏈接:

* PHP5: const vs static

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