__get方法如果不返回值的話empty()就一直返回true,在empty()調(diào)用時(shí)會(huì)先調(diào)用__isset再調(diào)用__get,__isset返回false,empty()就與之相反取true而不會(huì)調(diào)用__get,__isset返回true,就會(huì)調(diào)用__get,當(dāng)有返回值時(shí)相當(dāng)于true,所以結(jié)果為false,這相當(dāng)于一個(gè)或關(guān)系。empty(false|true) = true|false = true,empty(true|true)=false|false=false。

在第二張截圖中 ? getting the property classname ?這個(gè)值是從哪里來的啊?

class?MagicTest{
????
????public?function?__get($name){
?????return?"Getting?the?property".$name."<br/>";
????}
????
????public?function?__set($name,$value){
????????echo?"setting?the?property".$name."to?value".$value."<br/>";
????}
????public?function?__isset($name){
????????echo?"__isset?invoked<br/>";
????????return?true;
????}
????public?function?__unset($name){
????????echo?"unsetting?property".$name."<br/>";
????????
????}?
}
$obj=new?MagicTest();
echo?$obj->className."<br/>";
$obj->className="MagicClassX"."<br/>";
echo?'$obj->className?is?set?'.isset($obj->className)."<br/>";
echo?'$obj->className?is?empty?'.empty($obj->className)."<br/>";
unset($obj->className);

按照我的寫法 是正常顯示的啊 ? ?你在試試