本节内容：
php多构造器的类
在php编程中，实例化一个类时，需要根据构造方法的参数个数进行初始化不用的内容，类似php函数或方法的可选参数。
来看例子：
复制代码 代码示例:
<?php
/**
* php 多构造器的类
* by www.jb200.com
*/
class A {
public function __construct() {
$a = func_get_args();
$i = func_num_args();
if (method_exists($this,$f='__construct'.$i)) {
call_user_func_array(array($this,$f),$a);
}
}
public function __construct1($a1) {
echo '__construct with 1 param called: '.$a1.PHP_EOL;
}
public function __construct2($a1,$a2) {
echo '__construct with 2 params called: '.$a1.','.$a2.PHP_EOL;
}
public function __construct3($a1,$a2,$a3) {
echo '__construct with 3 params called: '.$a1.','.$a2.','.$a3.PHP_EOL;
}
}
$o = new A('sheep');
$o = new A('sheep','cat');
$o = new A('sheep','cat','dog');
// 结果:
// __construct with 1 param called: sheep
// __construct with 2 params called: sheep,cat
// __construct with 3 params called: sheep,cat,dog
?>
