1. __construct: 

     内置构造函数，在对象被创建时自动调用。见如下代码：

    arg1 = $arg1;        $this->arg2 = $arg2;        print "__construct is called...\n";    }    public function printAttributes() {        print '$arg1 = '.$this->arg1.' $arg2 = '.$this->arg2."\n";    }}$testObject = new ConstructTest("arg1","arg2"); $testObject->printAttributes();

2. parent: 

     用于在子类中直接调用父类中的方法，功能等同于Java中的super。 

<?php

class BaseClass {

protected $arg1;

protected $arg2;

function __construct($arg1, $arg2) {

$this->arg1 = $arg1;

$this->arg2 = $arg2;

print "__construct is called...\n";

}

function getAttributes() {

return '$arg1 = '.$this->arg1.' $arg2 = '.$this->arg2;

}

}

class SubClass extends BaseClass {

protected $arg3;

function __construct($baseArg1, $baseArg2, $subArg3) {

parent::__construct($baseArg1, $baseArg2);

$this->arg3 = $subArg3;

}

function getAttributes() {

return parent::getAttributes().' $arg3 = '.$this->arg3;

}

}

$testObject = new SubClass("arg1","arg2","arg3");

print $testObject->getAttributes()."\n";

3. self:

     在类内调用该类静态成员和静态方法的前缀修饰，对于非静态成员变量和函数则使用this。