php 面向对象：this 关键字

 1 <?php 2 class A{ 3 ????private $a = 99; 4 ????//这里写一个打印参数的方法. 5 ????public function printInt($a){ 6 ????????echo "这里的 \$a 是传递的参数 $a "; 7 ????????echo "<br>"; 8 ????????echo "这里的 \$this->a 是属性 $this->a"; 9 ????}10 }11 12 $a = new A(); // 这里的$a 可不是类中的任何一个变量了.13 $a->printInt(88);

 1 <?php 2 //写一个类,让他自动完成最大值的换算 3 class Math{ 4 ????//两个数值比较大小. 5 ????public function Max($a,$b){ 6 ????????return $a>$b?$a:$b; ?????7 ????} 8 ????//三个数值比较大小. 9 ????public function Max3($a,$b,$c){10 ????????//调用类中的其它方法.11 ????????$a = $this->Max($a,$b);12 ????????return $this->Max($a,$c); ??????13 ????}14 }15 $math = new Math();16 echo "最大值是 ".$math->Max3(99,100,88);

 1 <?php 2 class A{ 3 ????private $a = 0; 4 ????public function __construct(){ 5 ????????$this->a = $this->a + 1 ; 6 ????} 7 ??????8 ????public function doSomeThing(){ 9 ????????$this->__construct();10 ????????return $this->a;11 ????} ????12 }13 $a = new A(); // 这里的$a 可不是类中的任何一个变量了.14 echo "现在 \$a 的值是" . $a->doSomeThing();

 1 <?php 2 class A{ 3 ????public function ?getASelf(){ 4 ????????return $this; 5 ????} 6 ????public function __toString(){ 7 ????????return "这是类A的实例."; ?????8 ????} ??9 }10 $a = new A(); // 创建A的实例;11 $b = $a->getASelf(); //调用方法返回当前实例.12 echo $a; //打印对象会调用它的__toString方法.

 1 <!-- 通过$this 传递对象 ?2 在这个例子中,我们写一个根据不同的年龄发不同工资的类. 3 我们设置处理年龄和工资的业务模型为一个独立的类. 4 --> 5 <?php 6 class User{ 7 ????private $age ; ?8 ????private $sal ; 9 ????private $payoff ; //声明全局属性.10 ????11 ????//构造函数,中创建Payoff的对象.12 ????public function __construct(){13 ????????$this->payoff = new Payoff();14 ????} ???15 ????public function getAge(){16 ????????return $this->age;17 ????}18 ????public function setAge($age){19 ????????$this->age = $age;20 ????} ???21 ????// 获得工资.22 ????public ????function getSal(){23 ????????$this->sal = ?$this->payoff->figure($this);24 ????????return $this->sal;25 ????}26 }27 //这是对应工资与年龄关系的类.28 class Payoff{29 ????public function figure($a){30 ????????$sal =0;31 ????????$age = $a->getAge();32 ????????if($age >80 || $age <16 ){33 ????????????$sal = 0;34 ????????}elseif ($age > 50){35 ????????????$sal = 1000;36 ????????}else{37 ????????????$sal = 800;38 ????????}39 ????????return $sal;40 ????}41 }42 //实例化User43 $user = new User();44 45 $user->setAge(55);46 echo $user->getAge()."age ,his sal is " . $user->getSal();47 echo "<br>";48 49 $user->setAge(20);50 echo $user->getAge()."age , his sal is " . $user->getSal();51 echo "<br>";52 53 $user->setAge(-20);54 echo $user->getAge()."age , his sal is " . $user->getSal();55 echo "<br>";56 57 $user->setAge(150);58 echo $user->getAge()."age , his sal is " . $user->getSal();