属性重载
实例
<?php
namespace _1008;
class Demo1
{
public $product;
//变成静态 static
public static $price;
public function __construct($product, $price)
{
$this->product = $product;
self::$price = $price;
}
public function test(){
return self::$price;
}
}
$obj = new Demo1('电脑', 4890);
echo '品名: '. $obj->product, ', 价格: ', Demo1::$price;
//echo '<br>', Demo1::test();
echo '<br>', $obj->test();运行实例 »
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回调函数
实例
<?php
namespace _1008;
class Demo2
{
private $name;
private $salary;
protected $secret= '1111111111';
public function __construct($name, $salary)
{
$this ->name = $name;
$this ->salary = $salary;
}
public function __get($name)
{
if($name === 'secret'){
return ($this ->name ==='admin')? $this->$name : '无权查看';
}
return $this->name;
}
public function __set($name, $value)
{
if($name==='salary'){
return $this->name === 'admin' ? $this->$name =$value :'无权更新';
}
return $this->$name= $value;
}
public function __isset($name)
{
return isset($this ->$name);
}
public function __unset($name)
{
unset($this ->$name);
}
}
$obj = new Demo2('admin', 6666);
// echo $obj->secret;
echo '<br>';
$obj->salary =9999;
echo $obj->salary;
// echo $obj->name, '<br>';
// $obj->salary = 2;
// echo $obj->salary;
// echo '<hr>';
// echo isset ( $obj->salary) ? '存在' :'不存在';
// unset($obj->salary);
// echo $obj->salary;运行实例 »
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方法重载
实例
<?php
namespace _1008;
function sum($a,$b)
{
return "{$a}+{$b} =" .($a+$b);
}
echo call_user_func_array( __NAMESPACE__.'\sum',[50,30]);
class test1{
public function sum($a,$b)
{
return "{$a}-{$b} =" .($a-$b);
}
}
$obj= new test1();
echo '<br>';
echo call_user_func_array([$obj,'sum'],[40,20]);
class test2{
public static function sum($a,$b)
{
return "{$a}*{$b} =" .($a*$b);
}
}
$obj= new test2();
echo '<br>';
echo call_user_func_array([$obj,'sum'],[20,20]);
class test3{
public static function sum($a,$b)
{
return "{$a}/{$b} =" .($a/$b);
}
}
echo '<br>';
echo call_user_func_array([test3::class,'sum'],[20,20]);
class demo3
{
public function __call($name,$args){
return '方法是:'.$name.'<br>参数列表:<pre>'.print_r($args, true);
}
public static function __callstatic($name,$args){
return '方法是:'.$name.'<br>参数列表:<pre>'.print_r($args, true);
}
}
echo '<br>';
$obj =new demo3();
echo $obj->getinfo1(10,20,30);
echo demo3::getinfo2('html','css','js');运行实例 »
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数据库链接调用 demo4.php
实例
<?php
namespace _1008;
class query{
public $pdo = null;
public $table;
public $field;
public $where;
public $limit;
public function __construct($pdo){
$this->pdo=$pdo;
}
// 设置数据表名称
public function table($tableName)
{
$this->table = $tableName;
//返回当前类实例, 用来链式调用后面的其它方法
return $this;
}
// 设置数据表字段
public function field($fields = '*')
{
$this->field = empty($fields) ? '*' : $fields;
return $this;
}
// 设置查询条件
public function where($where = '')
{
$this->where = empty($where) ? $where : ' WHERE '. $where;
return $this;
}
// 设置显示数量
public function limit($limit)
{
$this->limit = empty($limit) ? $limit : ' LIMIT '. $limit;
return $this;
}
public function select()
{
// SELECT * FROM table WHERE **** LIMIT n
// 拼装SQL
$sql = 'select '
. $this->field // 字段列表
. ' from '
. $this->table // 数据表
. $this->where // 条件
. $this->limit; // 显示数量
// 预处理
$stmt = $this->pdo->prepare($sql);
$stmt->execute();
// die($stmt->debugDumpParams()); // 查看生成的sql
return $stmt->fetchAll(\PDO::FETCH_ASSOC);
}
}运行实例 »
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demo5.php
实例
<?php
namespace _1008;
require 'demo4.php';
class db{
protected static $pdo = null;
public static function connection(){
self::$pdo=new \pdo('mysql:host=127.0.0.1;dbname=php','root','root');
}
public static function __callstatic($name, $arguments){
self::connection();
$query=new query(self::$pdo);
return call_user_func_array([$query,$name],$arguments);
}
}
$staffs=db::table('staff')
->field('staff_id,name,position, mobile')
->where('staff_id > 1')
->limit(1)
->select();
foreach ($staffs as $staff){
print_r($staffs);
echo'<br>';
}运行实例 »
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