您的位置 首页 php

关于PHP中单例模式的实现

由于我以前是做java开发的,在使用单例模式的时候,首先想到的想用饿汉式,然后发现在PHP中,有这样一个特性:因为PHP不支持在类定义时给类的成员变量赋予非基本类型的值。如表达式,new操作等等。转而想要确保这个单例模式的原子性,发现PHP中也没有像JAVA中的线程安全问题。

嘿嘿,你说PHP好不好?那么OK接下来就试试PHP的懒汉式单例模式了。

相关推荐:《PHP教程》

一、三私一公:

①、私有静态属性,又来储存生成的唯一对象

②、私有构造函数

③、私有克隆函数,防止克隆——clone

④、公共静态方法,用来访问静态属性储存的对象,如果没有对象,则生成此单例

二、关键词instanceof

检查此变量是否为该类的对象、子类、或是实现接口。

1、一个private的__construct是必须的,单例类不能在其它类中实例化,只能被自身实例化;

2、拥有一个保存类的实例的静态成员变量;

3、一个静态的公共方法用于实例化这个类,并访问这个类的实例;

  class SingleInstance{                private function _construct(){                    }               private static $instance;              private function _clone(){                  }       public static function getInstance(){                      if(!self::$instance instanceof SingleInstance){               self::$instance=new SingleInstance();           }           return self ::$instance;                  }           }

以上就是关于PHP中单例模式的实现的详细内容,更多请关注求知技术网其它相关文章!

文章来源:智云一二三科技

文章标题:关于PHP中单例模式的实现

文章地址:https://www.zhihuclub.com/2490.shtml

关于作者: 智云科技

热门文章

评论已关闭

35条评论

  1. Many doctors believe that Cialis can provide a quick kick in the teeth to clear excess fat from the body Older men 65-year-olds should start at 25 mg before sexual activity

  2. Remission Reconstruction Ceremonies for the Medical School, Dental School, School of Allied Health Sciences and School of Nursing were May 22

  3. The stage of cancer, or extent of disease, is based on information gathered through the various tests done as the diagnosis and workup of the cancer is being performed

  4. A nationwide study is under way to determine whether a drug called raloxifene, which may reduce breast cancer risk without raising the risk of endometrial cancer, prevents breast cancer as effectively as tamoxifen does

  5. The Commission noted that there is a strong temptation to frame attendance or other measures of the time at which functions must be performed as essential functions, but that represents a flawed understanding of the requirements and structure of the Rehabilitation Act

  6. Conflict of interest and disclosure The authors declare that they have no conflicts of interest or financial disclosures Figure 1 Open in a disjoined window Masson s trichrome staining of ovarian buy ascorbic acid pharmacy online tissues examined under pounce microscopy

  7. a Progesterone receptor immunostaining intensity in mammary epithelial cells are shown for wild type WT FVB N n 6 and lines D n 6 and F n 8 ERО”3 female mice

  8. When you are at an all time baseline testosterone level, then you do an initial cycle with 50 mg then the cycle will go like an 8 week cycle with 1 mg and then the cycle will go like an 8 week cycle with 1 mg and after 12 weeks out of a 10 week cycle, where you get the 1 2 increase in testosterone, you do another initial cycle of 1 mg then the cycle will go like an 8 week cycle with 1 2 increase then you use the same cycle of Dbol with the 1 2 increase and a final cycle of 1 mg 03 Three ounces of meat is a serving about the size of a deck of cards

  9. To our knowledge, this is the first study to imply that MDSCs are affected by endocrine therapy

  10. It is important to review the drugs administered to the patient as some pharmaceutical agents can cause or worsen fatigue

  11. Long Term Surveillance of Papillary Thyroid Cancer Patients Who Do Not Undergo Postoperative Radioiodine Remnant Ablation Is There a Role for Serum Thyroglobulin Measurement

  12. Given the above concerns, let s examine the data on berberine, one of the principal isoquinoline alkaloids in goldenseal Paediatr Perinat Epidemiol 1998 Apr; 12 2 176 81

  13. That is why we need to take a holistic approach and leave no stone unturned in our quest to normalize your thyroid and improve your health in general Acupuncture is widely used for the infertile female because of it is non- invasive and has fewer side effects, but the powerful evidence for the clinic is still insufficient

  14. Ricci F, Borzellino G, Ghimenton C, Cordiano C Letter to the Michigan Department of Community Health regarding the LipoTron Device HRG Publication 2051 Public Citizen calls upon the Michigan Department of Community Health to promptly investigate two health spas that are actively promoting and using the LipoTron medical device, which has not been cleared or approved by the Food and Drug Administration

  15. Now, a new study shows that men taking testosterone therapy for just over half a year could gain a few pounds of muscle mass and lose a

  16. 72 In this double blind phase III randomized controlled trial, patients who have been on first line non steroidal AI with CDK4 6 inhibitor palbociclib or abemaciclib for 6 months are centrally screened for ESR1 mutations in ctDNA every 2 3 months Withdrawal of medications may be through abrupt withdrawal, tapering to complete withdrawal or dose reduction

  17. These guys had their testosterone increase more than half again what they were normally producing just from taking 20mg Nolvadex per day

  18. Moreover, not surprisingly, patients with volume overload were more likely to require treatment intensification with diuretic agents and experience cardiovascular death or hospitalization for HF 220 Progestogen based methods such as depot medroxyprogesterone acetate, IUD with progestogen or progestogen only pills have a poorly investigated but possible increased risk of cancer recurrence, but may be used if positive effects outweigh this possible risk

网站地图