php系统常量魔术方法说明和魔术变量用法实例总结

<?php   
$basedir = dirname(FILE);   
echo $basedir  
//将在页面打印出一个这个文件所在绝对路径!  
?>

<?php
/**
在你的公用的配置文件中，来设置你的根目录，这样就不用担心经常搬家了。
*/
define(&#39;ROOT_PATH&#39;, dirname(FILE) . DIRECTORY_SEPARATOR);
echo ROOT_PATH;
echo "<br>";
echo FILE;
echo "<br>";
echo dirname(FILE);
echo "<br>";
echo dirname(dirname(FILE));
?>

<?php
echo LINE;  //显示，LINE所在的行号
?>

<?php
class base_class
{
function say_a()
{
echo "&#39;a&#39; – said the " . CLASS . "<br/>";
}
function say_b()
{
echo "&#39;b&#39; – said the " . get_class($this) . "<br/>";
}
}
class derived_class extends base_class
{
function say_a()
{
parent::say_a();
echo "&#39;a&#39; – said the " . CLASS . "<br/>";
}
function say_b()
{
parent::say_b();
echo "&#39;b&#39; – said the " . get_class($this) . "<br/>";
}
}
$obj_b = new derived_class();
$obj_b->say_a();
echo "<br/>";
$obj_b->say_b();
?>

'a' – said the base_class
'a' – said the derived_class
'b' – said the  derived_class
'b' – said the derived_class

<?php
class test
{
function a()
{
echo FUNCTION;
echo "<br>";
echo METHOD;
}
}
function good (){
echo FUNCTION;
echo "<br>";
echo METHOD;
}
$test = new test();
$test->a();
echo "<br>";
good();
?>

a
test::a
good
good

<?php
if(!defined(&#39;DIR&#39;)) {
$iPos = strrpos(FILE, "/");
define("DIR", substr(FILE, 0, $iPos) . "/");
}
?>

<?php
//php5.3
class Model
{
public static function find()
{
echo STATIC;
}
}
class Product extends Model {}
class User extends Model {}
Product::find(); // "Product"
User::find(); // "User"
?>