PHP面向对象程序设计之对象生成方法详解
本文实例讲述了PHP面向对象程序设计之对象生成方法。分享给大家供大家参考，具体如下：
对象
看个例子
<?php
abstractclassEmployee{//雇员
protected$name;
function__construct($name){
$this->name=$name;
}
abstractfunctionfire();
}
classMinionextendsEmployee{//奴隶继承雇员
functionfire(){
print"{$this->name}:I'llclearmydesk\n";
}
}
classNastyBoss{//坏老板
private$employees=array();
functionaddEmployee($employeeName){//添加员工
$this->employees[]=newMinion($employeeName);//代码灵活性受到限制
}
functionprojectFails(){
if(count($this->employees)>0){
$emp=array_pop($this->employees);
$emp->fire();//炒鱿鱼
}
}
}
$boss=newNastyBoss();
$boss->addEmployee("harry");
$boss->addEmployee("bob");
$boss->addEmployee("mary");
$boss->projectFails();
//output:
//mary:I'llclearmydesk
?>
再看一个更具有灵活性的案例
<?php
abstractclassEmployee{
protected$name;
function__construct($name){
$this->name=$name;
}
abstractfunctionfire();
}
classMinionextendsEmployee{
functionfire(){
print"{$this->name}:I'llclearmydesk\n";
}
}
classNastyBoss{
private$employees=array();
functionaddEmployee(Employee$employee){//传入对象
$this->employees[]=$employee;
}
functionprojectFails(){
if(count($this->employees)){
$emp=array_pop($this->employees);
$emp->fire();
}
}
}
//newEmployeeclass...
classCluedUpextendsEmployee{
functionfire(){
print"{$this->name}:I'llcallmylawyer\n";
}
}
$boss=newNastyBoss();
$boss->addEmployee(newMinion("harry"));//直接以对象作为参数，更具有灵活性
$boss->addEmployee(newCluedUp("bob"));
$boss->addEmployee(newMinion("mary"));
$boss->projectFails();
$boss->projectFails();
$boss->projectFails();
//output:
//mary:I'llclearmydesk
//bob:I'llcallmylawyer
//harry:I'llclearmydesk
?>
单例
<?php
classPreferences{
private$props=array();
privatestatic$instance;//私有的，静态属性
privatefunction__construct(){}//无法实例化，私有的构造函数
publicstaticfunctiongetInstance(){//返回对象静态方法才可以被类访问，静态方法中要有静态属性
if(empty(self::$instance)){
self::$instance=newPreferences();
}
returnself::$instance;
}
publicfunctionsetProperty($key,$val){
$this->props[$key]=$val;
}
publicfunctiongetProperty($key){
return$this->props[$key];
}
}
$pref=Preferences::getInstance();
$pref->setProperty("name","matt");
unset($pref);//removethereference
$pref2=Preferences::getInstance();
print$pref2->getProperty("name")."\n";//demonstratevalueisnotlost
?>
点评：不能随意创建对象，只能通过Preferences::getInstance()来创建对象。
工厂模式
<?php
abstractclassApptEncoder{
abstractfunctionencode();
}
classBloggsApptEncoderextendsApptEncoder{
functionencode(){
return"AppointmentdataencodedinBloggsCalformat\n";
}
}
classMegaApptEncoderextendsApptEncoder{
functionencode(){
return"AppointmentdataencodedinMegaCalformat\n";
}
}
classCommsManager{//负责生产Bloggs对象
functiongetApptEncoder(){
returnnewBloggsApptEncoder();
}
}
$obj=newCommsManager();
$bloggs=$obj->getApptEncoder();//获取对象
print$bloggs->encode();
?>
output:
AppointmentdataencodedinBloggsCalformat
进一步增加灵活性设置
<?php
abstractclassApptEncoder{
abstractfunctionencode();
}
classBloggsApptEncoderextendsApptEncoder{
functionencode(){
return"AppointmentdataencodedinBloggsCalformat\n";
}
}
classMegaApptEncoderextendsApptEncoder{
functionencode(){
return"AppointmentdataencodedinMegaCalformat\n";
}
}
classCommsManager{
constBLOGGS=1;
constMEGA=2;
private$mode;
function__construct($mode){
$this->mode=$mode;
}
functiongetHeaderText(){
switch($this->mode){
case(self::MEGA):
return"MegaCalheader\n";
default:
return"BloggsCalheader\n";
}
}
functiongetApptEncoder(){
switch($this->mode){
case(self::MEGA):
returnnewMegaApptEncoder();
default:
returnnewBloggsApptEncoder();
}
}
}
$man=newCommsManager(CommsManager::MEGA);
print(get_class($man->getApptEncoder()))."\n";
$man=newCommsManager(CommsManager::BLOGGS);
print(get_class($man->getApptEncoder()))."\n";
?>
output:
MegaApptEncoder
BloggsApptEncoder
工厂方法模式要把创建者类与要生产的产品类分离开来。
抽象工厂
通过抽象来来约束，成为一定的规矩。
<?php
abstractclassApptEncoder{
abstractfunctionencode();
}
classBloggsApptEncoderextendsApptEncoder{
functionencode(){
return"AppointmentdataencodedinBloggsCalformat\n";
}
}
classMegaApptEncoderextendsApptEncoder{
functionencode(){
return"AppointmentdataencodedinMegaCalformat\n";
}
}
abstractclassCommsManager{//预约
abstractfunctiongetHeaderText();
abstractfunctiongetApptEncoder();
abstractfunctiongetTtdEncoder();
abstractfunctiongetContactEncoder();
abstractfunctiongetFooterText();
}
classBloggsCommsManagerextendsCommsManager{
functiongetHeaderText(){
return"BloggsCalheader\n";
}
functiongetApptEncoder(){
returnnewBloggsApptEncoder();
}
functiongetTtdEncoder(){
returnnewBloggsTtdEncoder();
}
functiongetContactEncoder(){
returnnewBloggsContactEncoder();
}
functiongetFooterText(){
return"BloggsCalfooter\n";
}
}
classMegaCommsManagerextendsCommsManager{
functiongetHeaderText(){
return"MegaCalheader\n";
}
functiongetApptEncoder(){
returnnewMegaApptEncoder();
}
functiongetTtdEncoder(){
returnnewMegaTtdEncoder();
}
functiongetContactEncoder(){
returnnewMegaContactEncoder();
}
functiongetFooterText(){
return"MegaCalfooter\n";
}
}
$mgr=newMegaCommsManager();
print$mgr->getHeaderText();
print$mgr->getApptEncoder()->encode();//对象调用方法，返回对象，继续调用方法。
print$mgr->getFooterText();
?>
output:
MegaCalheader
AppointmentdataencodedinMegaCalformat
MegaCalfooter
更加牛逼的实现
<?php
//根据类图，规划类的代码。从大局入手。
abstractclassApptEncoder{
abstractfunctionencode();
}
classBloggsApptEncoderextendsApptEncoder{
functionencode(){
return"AppointmentdataencodedinBloggsCalformat\n";
}
}
classMegaApptEncoderextendsApptEncoder{
functionencode(){
return"AppointmentdataencodedinMegaCalformat\n";
}
}
abstractclassCommsManager{
constAPPT=1;
constTTD=2;
constCONTACT=3;
abstractfunctiongetHeaderText();
abstractfunctionmake($flag_int);//int标记
abstractfunctiongetFooterText();
}
classBloggsCommsManagerextendsCommsManager{
functiongetHeaderText(){
return"BloggsCalheader\n";
}
functionmake($flag_int){
switch($flag_int){
caseself::APPT://self直接控制常量
returnnewBloggsApptEncoder();
caseself::CONTACT:
returnnewBloggsContactEncoder();
caseself::TTD:
returnnewBloggsTtdEncoder();
}
}
functiongetFooterText(){
return"BloggsCalfooter\n";
}
}
$mgr=newBloggsCommsManager();
print$mgr->getHeaderText();
print$mgr->make(CommsManager::APPT)->encode();
print$mgr->getFooterText();
?>
output:
BloggsCalheader
AppointmentdataencodedinBloggsCalformat
BloggsCalfooter
原型模式
改造成一个保存具体产品的工厂类。
<?php
classSea{}//大海
classEarthSeaextendsSea{}
classMarsSeaextendsSea{}
classPlains{}//平原
classEarthPlainsextendsPlains{}
classMarsPlainsextendsPlains{}
classForest{}//森林
classEarthForestextendsForest{}
classMarsForestextendsForest{}
classTerrainFactory{//地域工厂
private$sea;
private$forest;
private$plains;
function__construct(Sea$sea,Plains$plains,Forest$forest){//定义变量为类对象
$this->sea=$sea;
$this->plains=$plains;
$this->forest=$forest;
}
functiongetSea(){
returnclone$this->sea;//克隆
}
functiongetPlains(){
returnclone$this->plains;
}
functiongetForest(){
returnclone$this->forest;
}
}
$factory=newTerrainFactory(newEarthSea(),
newEarthPlains(),
newEarthForest());
print_r($factory->getSea());
print_r($factory->getPlains());
print_r($factory->getForest());
?>
output:
EarthSeaObject ( ) EarthPlainsObject ( ) EarthForestObject ( )
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