看php手册2015-03-19版后备注
类与对象->基本概念:
1,#############################
::class
自 PHP 5.5 起,关键词 class 也可用于类名的解析。使用 ClassName::class 你可以获取一个字符串,包含了类 ClassName 的完全限定名称。这对使用了 命名空间 的类尤其有用。
Example #7 类名的解析as stated in the docs is:
namespace NS {
class ClassName {
}
echo ClassName::class;
}
?>
以上例程会输出:
NS\ClassName
2,#############################
Just to be clear: the correct way of validating a classname, as stated in the docs is:
$valid = preg_match('/^[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*$/', $className);
3,#############################
属性中的变量可以初始化,但是初始化的值必须是常数,这里的常数是指 PHP 脚本在编译阶段时就可以得到其值,而不依赖于运行时的信息才能求值
PHP 5.3.0 新增 支持Nowdoc声明类属性; 不包含变量的heredoc也是可以的,包含变量就错。
new static() 会遵循继承关系,new 的是子类
new self() 不会被继承,new 的是 self 这个词所在的那个类
###
As of PHP 5.6 you can finally define constant using math expressions, like this one:
class MyTimer {
const SEC_PER_DAY = 60 * 60 * 24;
}
?>
###
自 PHP 5.3.3 起,在命名空间中,与类名同名的方法不再作为构造函数。这一改变不影响不在命名空间中的类。
namespace Foo;
class Bar {
public $a;
public function Bar() {
$this->a = 'to here';
}
public function getA(){
return $this->a;
}
}
$bar = new Bar();
echo $bar->getA(); //空 ; 去掉命名空间则输出 to here;
###
自 PHP 5.3.0 起,可以通过变量来引用类,该变量的值不能是关键字(如 self,parent 和 static)。
带整理:
self,parent 和 static
public(公有),protected(受保护)或 private(私有)

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Thesession.gc_maxlifetimesettinginPHPdeterminesthelifespanofsessiondata,setinseconds.1)It'sconfiguredinphp.iniorviaini_set().2)Abalanceisneededtoavoidperformanceissuesandunexpectedlogouts.3)PHP'sgarbagecollectionisprobabilistic,influencedbygc_probabi

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