search
HomeBackend DevelopmentPHP Tutorial关于PHP类继承的问题

我现在自己编写了一个两个继承关系的类,父类实例化后子类不知道怎么调用父类已经实例后存储的变量
先把代码粘在下面:

Class Identification{	//Identification函数将name与code联系起来	public function Identification()	{		//连接到InfoModel		$DB_Info = M('Info');		$condition->Name = $this->name;		return $this->code = $DB_Info->where($condition)->getfield('Code');	}	public $name;	protected $code;}Class PT_Info extends Identification{	public function get_BloodTest()	{		$DB_BloodTest = M('Bloodtest');		$condition->Code = $this->code;		echo "This is Code:".$this->code;		$this->Info_BT_WBC = $DB_BloodTest->where($condition)->getfield('WBC');		echo "This is WBC:".$this->Info_BT_WBC;		$this->Info_BT_NEPer = $DB_BloodTest->where($condition)->getfield('NEPer');		echo "This is NE%:".$this->Info_BT_NEPer;		$this->Info_BT_LYPer = $DB_BloodTest->where($condition)->getfield('LY%');		echo "This is LY%:".$this->Info_BT_LYPer;		$this->Info_BT_MOPer = $DB_BloodTest->where($condition)->getfield('MO%');		echo "This is MO%:".$this->Info_BT_MOPer;	}		public $Info_BT_WBC;	public $Info_BT_NEPer;	public $Info_BT_LYPer;	public $Info_BT_MOPer;}public function tclass()	{		$neal = new Identification();		$neal->name = 'Neal';		$code = $neal->Identification();		$this->assign('name',$neal->name);		$this->assign('code',$code);		$neal_BT = new PT_Info();		$neal_BT->get_BloodTest();		$this->assign('Info_BT_WBC',$neal_BT->Info_BT_WBC);		$this->assign('Info_BT_NEPer',$neal_BT->Info_BT_NEPer);		$this->assign('Info_BT_LYPer',$neal_BT->Info_BT_LYPer);		$this->assign('Info_BT_MOPer',$neal_BT->Info_BT_MOPer);		$this->display();	}

如上面代码:我把Identification类实例化为neal后存储了一个变量$code,之后实例化其子类PT_Info为neal_BT,此时需要调用已经存储在neal中的$code变量值(详见PT_Info类里的函数用法)
我不想在PT_Info类里面再单独存一个$code变量,想借用继承关系,毕竟往后还有很多类似的结构,那样写的话整体会很乱
话句话说我先在实例化的子类要调用一个实例化的父类里的变量,这两个类在定义是有继承关系,可是实例化后我不知道怎么告诉编译器这两个类(neal和neal_BT)之间存在继承关系
注:我整个项目使用ThinkPHP框架写的,所以有的函数(比如‘M’方法)并非PHP默认的写法
跪求大神帮忙解答!!!


回复讨论(解决方案)

你的概念出问题了
Class PT_Info extends Identification 后
PT_Info 和 Identification 就是两个独立的类了,虽然 PT_Info 继承了 Identification 一些东西
这就和 你 不是 你父亲 是一个道理

Class Identification
{
    public function Identification()
你在 Identification 定义了 Identification 方法,这就是构造函数了(据说 php7 取消了这个 C++ 来的特征)
那么,你在实例化 PT_Info 时,这个 Identification 方法就会自动被执行 code 属性就已经有值了
注意:构造函数是没有返回值的(写了也没用)

因此 tclass 方法中的 $neal = new Identification(); 是没有意义的
后面还有 $neal_BT = new PT_Info();
就是说 $DB_Info->where($condition)->getfield('Code'); 被执行了两次,多了一次无用功

你的概念出问题了
Class PT_Info extends Identification 后
PT_Info 和 Identification 就是两个独立的类了,虽然 PT_Info 继承了 Identification 一些东西
这就和 你 不是 你父亲 是一个道理

Class Identification
{
    public function Identification()
你在 Identification 定义了 Identification 方法,这就是构造函数了(据说 php7 取消了这个 C++ 来的特征)
那么,你在实例化 PT_Info 时,这个 Identification 方法就会自动被执行 code 属性就已经有值了
注意:构造函数是没有返回值的(写了也没用)

因此 tclass 方法中的 $neal = new Identification(); 是没有意义的
后面还有 $neal_BT = new PT_Info();
就是说 $DB_Info->where($condition)->getfield('Code'); 被执行了两次,多了一次无用功


太感谢啦!!的确是我自己理解上的问题,您这个解释太及时了多谢多谢!!!
Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
How can you protect against Cross-Site Scripting (XSS) attacks related to sessions?How can you protect against Cross-Site Scripting (XSS) attacks related to sessions?Apr 23, 2025 am 12:16 AM

To protect the application from session-related XSS attacks, the following measures are required: 1. Set the HttpOnly and Secure flags to protect the session cookies. 2. Export codes for all user inputs. 3. Implement content security policy (CSP) to limit script sources. Through these policies, session-related XSS attacks can be effectively protected and user data can be ensured.

How can you optimize PHP session performance?How can you optimize PHP session performance?Apr 23, 2025 am 12:13 AM

Methods to optimize PHP session performance include: 1. Delay session start, 2. Use database to store sessions, 3. Compress session data, 4. Manage session life cycle, and 5. Implement session sharing. These strategies can significantly improve the efficiency of applications in high concurrency environments.

What is the session.gc_maxlifetime configuration setting?What is the session.gc_maxlifetime configuration setting?Apr 23, 2025 am 12:10 AM

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

How do you configure the session name in PHP?How do you configure the session name in PHP?Apr 23, 2025 am 12:08 AM

In PHP, you can use the session_name() function to configure the session name. The specific steps are as follows: 1. Use the session_name() function to set the session name, such as session_name("my_session"). 2. After setting the session name, call session_start() to start the session. Configuring session names can avoid session data conflicts between multiple applications and enhance security, but pay attention to the uniqueness, security, length and setting timing of session names.

How often should you regenerate session IDs?How often should you regenerate session IDs?Apr 23, 2025 am 12:03 AM

The session ID should be regenerated regularly at login, before sensitive operations, and every 30 minutes. 1. Regenerate the session ID when logging in to prevent session fixed attacks. 2. Regenerate before sensitive operations to improve safety. 3. Regular regeneration reduces long-term utilization risks, but the user experience needs to be weighed.

How do you set the session cookie parameters in PHP?How do you set the session cookie parameters in PHP?Apr 22, 2025 pm 05:33 PM

Setting session cookie parameters in PHP can be achieved through the session_set_cookie_params() function. 1) Use this function to set parameters, such as expiration time, path, domain name, security flag, etc.; 2) Call session_start() to make the parameters take effect; 3) Dynamically adjust parameters according to needs, such as user login status; 4) Pay attention to setting secure and httponly flags to improve security.

What is the main purpose of using sessions in PHP?What is the main purpose of using sessions in PHP?Apr 22, 2025 pm 05:25 PM

The main purpose of using sessions in PHP is to maintain the status of the user between different pages. 1) The session is started through the session_start() function, creating a unique session ID and storing it in the user cookie. 2) Session data is saved on the server, allowing data to be passed between different requests, such as login status and shopping cart content.

How can you share sessions across subdomains?How can you share sessions across subdomains?Apr 22, 2025 pm 05:21 PM

How to share a session between subdomains? Implemented by setting session cookies for common domain names. 1. Set the domain of the session cookie to .example.com on the server side. 2. Choose the appropriate session storage method, such as memory, database or distributed cache. 3. Pass the session ID through cookies, and the server retrieves and updates the session data based on the ID.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

DVWA

DVWA

Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software

MantisBT

MantisBT

Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

mPDF

mPDF

mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),