PHP5中的this,self和parent关键字详解_PHP教程

(1) this

1 <?php
2
3 class UserName
4 {
5 //定义属性
6 private name;
7
8 //定义构造函数
9 function __construct( name )
10 {
11 this->name = name; //这里已经使用了this指针
12 }
13
14 //析构函数
15 function __destruct(){}
16
17 //打印用户名成员函数
18 function printName()
19 {
20 print( this->name ); //又使用了this指针
21 }
22 }
23
24 //实例化对象
25 nameObject = new UserName( "heiyeluren" );
26
27 //执行打印
28 nameObject->printName(); //输出: heiyeluren
29
30 //第二次实例化对象
31 nameObject2 = new UserName( "PHP5" );
32
33 //执行打印
34 nameObject2->printName(); //输出：PHP5
35 ?>

1 <?php
2
3 class Counter
4 {
5 //定义属性，包括一个静态变量
6 private static firstCount = 0;
7 private lastCount;
8
9 //构造函数
10 function __construct()
11 {
12 this->lastCount = selft::firstCount; //使用self来调用静态变量,使用self调用必须使用::(域运算符号)
13 }
14
15 //打印最次数值
16 function printLastCount()
17 {
18 print( this->lastCount );
19 }
20 }
21
22 //实例化对象
23 countObject = new Counter();
24
25 countObject->printLastCount(); //输出 1
26
27 ?>

1 <?php
2
3 //基类
4 class Animal
5 {
6 //基类的属性
7 public name; //名字
8
9 //基类的构造函数
10 public function __construct( name )
11 {
12 this->name = name;
13 }
14 }
15
16 //派生类
17 class Person extends Animal //Person类继承了Animal类
18 {
19 public personSex; //性别
20 public personAge; //年龄
21
22 //继承类的构造函数
23 function __construct( personSex, personAge )
24 {
25 parent::__construct( "heiyeluren" ); //使用parent调用了父类的构造函数
26 this->personSex = personSex;
27 this->personAge = personAge;
28 }
29
30 function printPerson()
31 {
32 print( this->name. " is " .this->personSex. ",this year " .this->personAge );
33 }
34 }
35
36 //实例化Person对象
37 personObject = new Person( "male", "21");
38
39 //执行打印
40 personObject->printPerson(); //输出：heiyeluren is male,this year 21
41
42 ?>